JP2002075443A - Electrolyte component and electrochemical cell using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolyte component with excellent durability and electric charge transport characteristics, and to provide an electrochemical cell of small property deterioration with the passage of time. SOLUTION: The electrolyte component contains a salt expressed by the formula (1). In the formula (1), R1 and R2 represents substituents respectively, and Y represents an organic or inorganic cation. The electrochemical cell includes the above electrolyte component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel electrolyte composition and an electrochemical cell using the same, particularly to a non-aqueous secondary battery and a photoelectrochemical cell.

[0002]

2. Description of the Related Art Electrolytes used in electrochemical cells such as non-aqueous secondary batteries and dye-sensitized solar cells contain ions according to the purpose and have a function of transporting the ions between electrodes (called ion conduction). It is a medium to have. For example, transport of lithium ions is a problem in a lithium secondary battery, which is a typical nonaqueous secondary battery, and conductivity of iodine ions and iodine trimer ions is a problem in a dye-sensitized solar cell. In these batteries, generally, a solution system having high ion conductivity is often used as an electrolyte. However, there is a problem that exhaustion or leakage of a solvent when incorporated into the battery lowers the durability of the battery. Further, in a lithium secondary battery, a metal container must be used to seal the solution, so that the weight of the battery increases, and it is difficult to give a degree of freedom to the shape of the battery.

In order to overcome such disadvantages of the solution electrolyte, various electrolytes have been proposed in recent years. A so-called gel electrolyte in which a solution electrolyte is infiltrated into a polymer matrix is advantageous over a solution electrolyte in that the ionic conductivity is small and the battery performance is not reduced, but it is possible to completely suppress the volatilization of the solvent. It cannot solve the problem of the solution-based electrolyte completely. Further, a polymer electrolyte obtained by dissolving a salt in a polymer such as polyethylene oxide is expected to solve the problem of a solution electrolyte, but the ionic conductivity is not yet sufficient. On the other hand, imidazolium salts and pyridinium salts whose counter anions are BF ₄ ⁻ and (CF ₃ SO ₂ ) ₂ N ⁻ are liquid room temperature molten salts at room temperature and are used as electrolytes for lithium ion batteries.
Although it has been proposed, the mechanical strength of the electrolyte and the ionic conductivity are contradictory, and if the mechanical strength is increased by means such as increasing the viscosity of the molten salt itself or incorporating a polymer, the ionic conductivity may be reduced. Is seen to decrease. Further, in the above-mentioned electrolyte, the ionic conductivity has a large temperature dependency, and the ionic conductivity particularly at low temperatures is insufficient.

By the way, photovoltaic power generation, which converts light energy into electric energy, includes single-crystal silicon solar cells, polycrystalline silicon solar cells, amorphous silicon solar cells,
Compound solar cells such as cadmium telluride and indium copper selenide have been put into practical use or are subject to research and development.However, in order to spread them, problems such as manufacturing costs, securing of raw materials, and long energy payback time have been identified. It needs to be overcome. On the other hand, there have been proposed many solar cells using an organic material intended to have a large area and a low price. However, there is a problem that conversion efficiency is low and durability is poor.

Under these circumstances, the technology of a photoelectric conversion element using an oxide semiconductor sensitized by a dye (hereinafter abbreviated as a dye-sensitized photoelectric conversion element) and a photoelectrochemical cell using the same are described in Nature ( Vol. 353, 737
740, 1991) and U.S. Pat. No. 4,927,721.
No., etc. The disclosed battery includes a photoelectric conversion element functioning as a negative electrode, a charge transport layer, and a counter electrode. The photoelectric conversion element includes a conductive support and a photosensitive layer, and the photosensitive layer includes a semiconductor having a surface on which a dye is adsorbed. The charge transport layer is made of an oxidation-reduction body, and performs charge transport between a negative electrode and a counter electrode (positive electrode). This type of battery is promising in that it is inexpensive and can provide relatively high energy conversion efficiency (photoelectric conversion efficiency). However, an aqueous solution (electrolyte solution) using a salt such as potassium iodide as an electrolyte is used as the charge transport layer. Therefore, when used for a long period of time, there is a problem that the photoelectric conversion efficiency is significantly reduced due to evaporation and depletion of the electrolytic solution, and the battery does not function as a battery.

[0006] To solve this problem, WO 95/18456 describes a method of using an imidazolium salt, which is a low-melting-point compound, as an electrolyte as a method for preventing depletion of the electrolyte. According to this method, the durability is improved because water or an organic solvent, which has been conventionally used as a solvent for the electrolyte, is unnecessary or requires only a small amount, but the durability is still insufficient in practical use. In addition, when the concentration of the imidazolium salt is increased, the viscosity increases, the charge transporting ability decreases, and the photoelectric conversion efficiency decreases. Furthermore, there is a method using a triazolium salt as an electrolyte, but this method also has the same problem as the imidazolium salt.

[0007]

In the conventional electrochemical cell, when an electrolyte composition containing a low molecular solvent is used, the battery performance is lowered due to the volatilization of the solvent and the leakage of the liquid, which results in a decrease in battery performance. There's a problem. On the other hand, when a so-called molten salt electrolyte based on a salt that is liquid at room temperature is used, it is effective to prevent deterioration of battery performance due to volatilization because it does not contain a compound having a low boiling point. There is a disadvantage that the charge transport ability is low because of its high value.

The present invention has been made in view of the above problems, and has as its object to provide an electrolyte composition having excellent durability and charge transport performance. It is another object of the present invention to provide an electrochemical cell in which the performance does not decrease over time.

[0009]

Means for solving the above problems are as follows. <1> The following general formula (1)
It is an electrolyte composition characterized by including the salt represented by these.

[0010]

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In the formula (1), R ₁ and R ₂ each represent a substituent, and Y represents an organic or inorganic cation.

<2> In the general formula (1), Y is an organic cation represented by any of the following general formulas (2-a), (2-b) and (2-c). The electrolyte composition according to the above.

[0013]

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In the formula (2-a), Q_y1Is 5 with the nitrogen atom
Or an atomic group capable of forming a 6-membered aromatic cation.
Then R_y1Is a substituted or unsubstituted alkyl group or alk
Represents a nyl group. In the formula (2-b), A_y1Is a nitrogen atom or
Represents an atom_y1, R_y2, R _y3And R_y4Are replacements
Or an unsubstituted alkyl or alkenyl group. Ma
R_y1, R_y2, R_y3And R_y4Two or more of each other
Combine and A_y1May form a non-aromatic ring containing
In the formula (2-c), R_y1, R_y2, R_y3, R_y4, R_y5And R
_y6Is a substituted or unsubstituted alkyl group or alkenyl, respectively.
R_y3, R_y4, R_y5And R_y6Two or more of
May combine with each other to form a ring structure. Equation (2
-A), a compound represented by the formula (2-b) and the formula (2-c)
Things are each Q _y1, R_y1, R_y2, R_y3, R_y4, R_y5Or R_y6
May form a multimer around the center.

<3> The electrolyte composition according to <1>, wherein in the general formula (1), Y is a lithium cation. <4> In the general formula (1), at least one of R ₁ and R ₂ contains a substituted or unsubstituted ethyleneoxy group <1>
It is an electrolyte composition in any one of <3>. <5> The electrolyte composition according to any one of <1> to <4>, wherein _one of R ₁ and R _{2 in} the general formula (1) contains a fluorine-substituted alkyl group. <6> The electrolyte composition according to any one of <1> to <5>, wherein in the general formula (1), at least one of R ₁ , R _2, and Y contains a polymerizable group. <7> The electrolyte composition according to any one of <1> to <5>, wherein in the general formula (1), at least one of an anion and a cation is a polymer. <8> The electrolyte composition according to any one of <1> to <7>, containing an iodine salt compound and iodine. <9> The salt represented by the general formula (1) is at least 2
At least one is a salt of a lithium cation, and the other is a salt of a cation wherein Y is represented by any of the general formulas (2-a), (2-b) and (2-c). The electrolyte composition according to any one of <3> to <8>.

<10> An electrochemical cell comprising the electrolyte composition according to any one of <1> to <9>. <11> A photoelectrochemical cell comprising a charge transport layer containing the electrolyte composition, a photosensitive layer containing a semiconductor sensitized with a dye, and a counter electrode, and being a photoelectrochemical cell. Electrochemical cell. <12> A non-aqueous secondary battery characterized by <10
The electrochemical cell according to <1>.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION [Electrolyte composition] The electrolyte composition of the present invention is characterized by containing a salt represented by the general formula (1). Generally, a compound that is a liquid or a solid having a low melting point at 25 ° C., a so-called molten salt, is advantageous in that it has a higher boiling point and is less likely to be depleted as compared with a low molecular solvent contained in a solvent electrolyte. . On the other hand, in general, there is a problem that the molten salt has a high viscosity and the charge transport ability is inferior to the solvent electrolyte. The electrolyte composition of the present invention containing the salt exhibits high charge transport performance in a high viscosity state, and thus has high durability without impairing the charge transport performance. Therefore, when used as an electrolyte of an electrochemical cell, it is possible to provide an electrochemical cell with little deterioration in performance over time and excellent durability.

In the general formula (1), R ₁ and R ₂ each represent a substituent. As the substituent represented by each of R ₁ and R ₂ , a substituted or unsubstituted alkyl group, alkoxy group and amino group are preferable. Among them, _one of R ₁ and R ₂ is a fluorinated alkyl group (preferably —CF ₃ , —C ₂ F ₅ , —C ₇
Whether the F _15, etc.), is preferably a group containing them. R ₁ and R ₂ may each further have a substituent, and the substituent is preferably a substituent exemplified as a substituent represented by R ₇ in the following general formula (3).

It is preferable that at least one of R ₁ and R ₂ contains a substituted or unsubstituted ethyleneoxy group. The substituent containing a substituted or unsubstituted ethyleneoxy group is represented by the following general formula (3).

[0020]

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In the general formula (3), R ₃ , R ₄ , R ₅ and R ₆ each represent a hydrogen atom or an alkyl group which may have a substituent. It is preferred that R _{3 to} R ₆ are all hydrogen atoms or one of them is a methyl group.

In the general formula (3), R ₇ represents a substituent. As R ₇ , a preferred substituent is an optionally substituted alkyl group [preferably having 1 carbon atom (C number).
To 24, more preferably (C number) is 1 to 10, and may be linear or branched, for example, methyl, ethyl, propyl, butyl, i-propyl, i
-Butyl, pentyl, hexyl, octyl, 2-ethylhexyl, t-octyl, decyl, dodecyl, tetradecyl, 2-hexyldecyl, hexadecyl, octadecyl, cyclohexylmethyl, octylcyclohexyl), substituted or fused A good aryl group (preferably having 6 to 24 carbon atoms, for example, phenyl, 4-methylphenyl, 3-cyanophenyl, 2-chlorophenyl, 2-naphthyl), a substituted or condensed heterocyclic group ( In the case of a nitrogen-containing heterocyclic group, the nitrogen in the ring may be quaternized, and preferably has 2 to 24 carbon atoms, for example, 4
-Pyridyl, 2-pyridyl, 1-octylpyridinium-4-yl, 2-pyrimidyl, 2-imidazolyl, 2-
Thiazolyl), an alkoxy group (preferably having 1 to 2 carbon atoms)
4, for example, methoxy, ethoxy, butoxy, octyloxy, methoxyethoxy, methoxypenta (ethyloxy), acryloyloxyethoxy, pentafluoropropoxy], an acyloxy group (preferably having 1 to 2 carbon atoms)
4, for example, acetyloxy, benzoyloxy), alkoxycarbonyl group (preferably having 2 to 24 carbon atoms, for example, methoxycarbonyl, ethoxycarbonyl), cyano group, fluoro group, alkoxycarbonyl group, cyano group,
And a polymerizable group (preferably a vinyl group, an acryloyl group, a methacryloyl group, a styryl group, a cinnamic acid residue, etc.)
Is mentioned.

In the general formula (3), n represents an integer of 1 to 20. n is preferably 3 to 20.
When n is 2 or more and when the general formula (1) contains two or more ethyleneoxy groups, they may be the same or different.

In the general formula (1), Y represents an organic or inorganic cation. When Y is an organic cation, the organic cation is represented by the general formula (2-a) or (2-b)
And an organic cation represented by any of (2-c).

In the above formula (2-a), Q _y1 represents an atomic group capable of forming a 5- or 6-membered aromatic cation together with a nitrogen atom. R _y1 represents a substituted or unsubstituted alkyl group or alkenyl group.

In the formula (2-b), A _y1 represents a nitrogen atom or a phosphorus atom, and R _y1 , R _y2 , R _y3 and R _y4 each represent a substituted or unsubstituted alkyl group or alkenyl group.
Two or more of R _y1 , R _y2 , R _y3 and R _y4 may combine with each other to form a non-aromatic ring containing A _y1 .

In the above formula (2-c), R _y1 , R _y2 , R _y3 ,
R _y4 , R _y5 and R _y6 each represent a substituted or unsubstituted alkyl group or alkenyl group. R _y1 , R _y2 , R _y3 , R
_y4, more than two may be bonded to form a ring structure of R _y5 and R _y6.

The formulas (2-a), (2-b) and
The cation represented by (2-c) is Q _y1, R_y1, R_y2,
R_y3, R_y4, R_y5Or R_y6To form multimers around
May be.

In the above formula (2-a), the constituent atoms of the atomic group represented by Q _y1 are preferably atoms selected from carbon, hydrogen, nitrogen, oxygen and sulfur. As the aromatic 6-membered ring completed by Q _y1 and a nitrogen atom, pyridine, pyrimidine, pyridazine, pyrazine and triazine are preferable, and pyridine is more preferable. As the aromatic 5-membered ring completed by Q _y1 and a nitrogen atom, oxazole, thiazole, imidazole, pyrazole, isoxazole, thiadiazole, oxadiazole and triazole are preferable, oxazole, thiazole and imidazole are preferable, and oxazole and imidazole are preferable. Is particularly preferred.

The formulas (2-a), (2-b) and (2-
The substituted or unsubstituted alkyl group of R _{y1 to} R _y6 in c) is preferably an alkyl group having 1 to 24 carbon atoms (hereinafter referred to as C number). The alkyl group may be linear, branched, or cyclic. For example, methyl, ethyl, propyl, butyl, i-propyl, pentyl, hexyl, octyl, 2-ethylhexyl, t
-Octyl, decyl, dodecyl, tetradecyl, 2-hexyldecyl, octadecyl, cyclohexyl, cyclopentyl and the like. The substituted or unsubstituted alkenyl group is preferably an alkenyl group having 2 to 24 carbon atoms. The alkenyl group may be linear or branched. For example, vinyl, allyl and the like can be mentioned. R _{y1 to} R _y6 are preferably an alkyl group having 3 to 18 carbon atoms and an alkenyl group having 2 to 18 carbon atoms, and more preferably an alkyl group having 4 to 6 carbon atoms.

The constituent atoms of the atomic group represented by Q _y1 and R _y1
When -R _y6 can be substituted, they may have a substituent. Preferred examples of the substituent include a halogen atom (F, Cl, Br, I), a cyano group, an alkoxy group (e.g., methoxy, ethoxy, methoxyethoxy), an aryloxy group (e.g., phenoxy), an alkylthio group (e.g., methylthio, ethylthio) ), Acyl group (acetyl, propionyl, benzoyl, etc.), sulfonyl group (methanesulfonyl, benzenesulfonyl, etc.), acyloxy group (acetoxy, benzoyloxy, etc.), sulfonyloxy group (methanesulfonyloxy, toluenesulfonyloxy, etc.), phosphonyl Group (such as diethylphosphonyl), amide group (such as acetylamino and benzoylamide), carbamoyl group (such as N, N-dimethylcarbamoyl and N-phenylcarbamoyl), and alkyl group (such as methyl, ethyl, propyl, and isoprene). Pills, cyclopropyl, butyl, 2-carboxyethyl, benzyl, etc.),
Aryl group (phenyl, toluyl, etc.), heterocyclic group (eg, pyridyl, imidazolyl, furanyl, etc.), alkenyl group (vinyl, 1-propenyl, etc.), polymerizable group (vinyl group, acryloyl group, methacryloyl group, styryl group and Cinnamic acid residue) and the like.

When Y is an inorganic cation, examples of the inorganic cation include an alkali metal ion (eg, lithium ion, sodium ion), an alkaline earth metal (eg, magnesium ion), and an ammonium ion. When the electrolyte composition of the present invention is used for an electrolyte for a lithium secondary battery, a salt containing a lithium ion as a cation can be used.

In the above general formula (1), when at least one of R ₁ , R ₂ and Y contains a polymerizable group (including the case where R ₁ and R ₂ themselves are polymerizable groups), the electrolyte composition It is preferred when the product is used after being polymerized. As the polymerizable group, an ethylenically unsaturated group (for example, an acryloyl group, a methacryloyl group, a styryl group, etc.) is preferable,
Particularly, an acryloyl group is preferable.

The specific examples of the salts represented by the above general formula (1) (Exemplary compounds F-1 to 29) are shown below, but the salts usable in the present invention are not limited to these specific examples. Yes. In addition, specific examples include salts formed by changing combinations of cations and anions in the specific examples.

[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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In the salt represented by the general formula (1),
Cation (Y) and / or anionic (R ₁ -CO-N ^{- -}
SO ₂ —R ₂ ) may be a polymer. When the anion is a polymer, R ₁ —CO—N ⁻ which is an anion of the salt is used.
Although the partial structure represented by —SO ₂ —R ₂ is included as a repeating unit constituting the main chain of the polymer, it is included as a partial structure of a side chain extending from the main chain of the polymer. Is also good. Further, the general formulas (2-a) to (2-
When the cation represented by any of c) is a polymer, the partial structure represented by any of the general formulas (2-a) to (2-c) constitutes a main chain of the polymer. Or as a partial structure of a side chain extended from the main chain of the polymer. The polymer having the partial structure is obtained by polymerizing an anion or a cation containing a polymerizable group in the structure alone or together with another monomer. For example, in the salt represented by the general formula (1), R ₁ and / or
Alternatively, it is obtained by polymerizing a compound in which R ₂ is a polymerizable group or has a polymerizable group as a substituent. Also,
In the cations represented by the general formulas (2-a) to (2-c), R _{y1 to} R _y6 are polymerizable groups or have a polymerizable group as a substituent, or an atom represented by Q _y1. The constituent atoms of the group are obtained by polymerizing a cation having a polymerizable group as a substituent.

The melting point of the salt represented by the general formula (1) is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and further preferably 60 ° C. or lower. The lower limit of the melting point is not particularly limited.

When the electrolyte composition of the present invention is incorporated into a battery, the electrolyte composition is heated and dissolved to be applied to or penetrated into the electrode, or a low-boiling solvent (eg, methanol, acetonitrile, methylene chloride) or the like is applied or permeated to the electrode. Thereafter, the solvent can be incorporated into the battery by, for example, removing the solvent by heating. Further, when the anion and / or cation of the salt represented by the general formula (1) contains a polymerizable group, it can be polymerized by heat or light after being incorporated into the electrode together with the polymerization initiator. .

The electrolyte composition of the present invention may be preferably used by mixing with a solvent or the like up to 50% by mass.
In order to realize excellent durability and photoelectric conversion efficiency, the salt represented by the general formula (1) is preferably contained in an amount of 70% by mass or more, more preferably 80% by mass or more, and preferably 90% by mass. It is most preferable to contain the above.

The chargeable composition of the present invention may contain, if desired, other components together with the salt represented by the general formula (1). The electrolyte composition of the present invention may contain a solvent together with the salt represented by the general formula (1). The content of the solvent in the electrolyte composition is preferably equal to or less than the content of the salt represented by the general formula (1). It is desirable that the solvent used is a compound having low viscosity to improve ionic mobility, or having high dielectric constant to improve the effective carrier concentration, and exhibiting excellent ionic conductivity. Such solvents include:
Ethylene carbonate, carbonate compounds such as propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, dioxane, ether compounds such as diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether,
Chain ethers such as polyethylene glycol dialkyl ether and polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether and polypropylene glycol monoalkyl ether, ethylene glycol , Polyhydric alcohols such as propylene glycol, polyethylene glycol, polypropylene glycol and glycerin, nitrile compounds such as acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile and benzonitrile, carboxylate esters, phosphate esters, phosphonate esters and the like Esters, dimethyl sulfoxide, sulfolane Throat aprotic polar substances, water, etc. can be used. Among them, ethylene carbonate, carbonate compounds such as propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, nitrile compounds such as benzonitrile, esters are particularly preferable. preferable. These may be used alone or in combination of two or more. The solvent preferably has a boiling point at normal pressure (1 atm) of 200 ° C. or higher from the viewpoint of improving durability by volatility resistance.
The temperature is preferably 50 ° C. or higher, more preferably 270 ° C. or higher, but is not limited to those having this property.

In the case where the salt has a polymerizable group and is polymerized before and after filling the battery, the charged composition of the present invention contains, together with the salt represented by the general formula (1), A polymerization initiator capable of initiating the polymerization of the salt may be contained. Further, other monomers (including a crosslinking agent) polymerizable with the salt represented by the general formula (1) can be contained. Polymerization includes general polymer synthesis described in Takayuki Otsu and Masayoshi Kinoshita: Experimental Methods for Polymer Synthesis (Chemical Doujin) and Takatsu Otsu: Lecture Polymerization Reaction Theory 1 Radical Polymerization (I) (Chemical Doujinshi) A radical polymerization method can be used, and both a thermal polymerization method using a thermal polymerization initiator and a photopolymerization method using a photopolymerization initiator can be used.

Examples of preferably used thermal polymerization initiators include, for example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2 ′ Azo initiators such as azobis (2-methylpropionate) and peroxide initiators such as benzoyl peroxide. Examples of preferably used photopolymerization initiators include α-carbonyl compounds (described in U.S. Pat. Nos. 2,367,661 and 2,367,670) and acyloin ethers (U.S. Pat.
828), α-hydrocarbon-substituted aromatic acyloin compounds (described in US Pat. No. 2,722,512),
Polynuclear quinone compounds (U.S. Pat.
51758), a combination of a triarylimidazole dimer and p-aminophenyl ketone (described in U.S. Pat. No. 3,493,676), acridine and phenazine compounds (JP-A-60-105667)
And US Pat. No. 4,239,850) and oxadiazole compounds (described in US Pat. No. 4,221,970). A preferable addition amount of the polymerization initiator in the electrolyte composition is 0.01% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 10% by mass or less based on the content of the salt. . Preferred molecular weight of polymer obtained by polymerization (number average molecular weight)
Is from 5,000 to when the salt is a monofunctional monomer.
1,000,000, and more preferably 10,000 to 500,000. When the salt is a polyfunctional monomer or when a crosslinking agent is used, the polymer having the above-mentioned molecular weight is 3%.
Form a three-dimensional network structure.

[0047] When the electrolyte composition of the present invention is used for an electrolyte of a photoelectrochemical cell, said in the electrolyte composition, I as charge carriers ^- and I ₃ ^- is preferably used in combination electrolyte containing, they It can be added in any salt form. I ₃ ^- salts, iodine salt ^- the presence of (I salt), was added iodine (I _2), cause produced in the electrolyte composition is common, in which the added I ₂ with the same amount of I ₃ ^- is generated. Therefore, when the electrolyte composition of the present invention is used for a photoelectrochemical cell, it is preferable that the electrolyte composition contains an iodine salt compound and iodine. As a preferable counter cation of the iodine salt compound, the aforementioned formula (2-
a), (2-b) or (2-c). In the electrolyte composition of the present invention, the concentration of I ⁻ is 10 to 10.
It is preferably 90% by mass, more preferably 30 to 70% by mass. At that time all remaining electrolyte components,
The salt represented by the general formula (1) is preferable. Further, in the electrolyte composition of the present invention, I ₃ ⁻ is preferably 0.1 to 50 mol% with respect to I ⁻ ,
-20 mol%, more preferably 0.5-10 mol%.
Mol%, more preferably 0.5 to 5 mol%.
Is most preferred.

The electrolyte composition of the present invention may contain another molten salt in addition to the salt. Examples of the molten salt preferably used in combination include those obtained by combining an organic cation represented by any of the general formulas (2-a), (2-b), and (2-c) with an arbitrary anion. Can be As the optional anion, a halide ion (Cl ⁻ , Br ⁻
Etc.), SCN ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , (CF ₃ S
O ₂ ) ₂ N ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , CH ₃ SO ₃ ⁻ ,
CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , Ph ₄ B ⁻ , (CF ₃ S
O _{2) 3} C ^-, and the like are _{^{preferable, SCN -, CF 3 SO 3}} -, CF 3
_{^{COO -, (CF 3 SO 2}} ) 2 N - or BF ₄ ^- and more preferable. Also, iodine salts such as LiI and CF ₃ CO
An alkali metal salt such as OLi, CF ₃ COONa, LiSCN, or NaSCN can also be added. The addition amount of the alkali metal salt is preferably about 0.02 to 2% by mass, and more preferably 0.1 to 1% by mass.

The electrolyte composition of the present invention contains LiI, Na
Metal iodides such as I, KI, CsI, and CaI ₂ ; iodide salts of quaternary imidazolium compounds; iodide salts of tetraalkylammonium compounds; Br ₂ and LiBr, NaB
r, KBr, CsBr, metal bromides such as CaBr _2;
Or Br ₂ and tetraalkyl ammonium bromide, bromine salts such as quaternary ammonium compounds pyridinium bromide; ferrocyanate - - ferricyanide or ferrocene metal complexes such as ferricinium ion; sodium polysulfide, alkylthiol - alkyl disulfide, etc. A viologen dye; hydroquinone-quinone; and the like. When they are contained, the amount of these compounds used is preferably 30% by mass or less based on the total mass of the electrolyte composition.

When the electrolyte composition of the present invention is used for a lithium ion battery, at least one of the compounds contained in the electrolyte composition uses a lithium salt whose cation is lithium ion. The lithium salt may be a salt represented by the general formula (1) (Y is a lithium ion) or another lithium salt. Other lithium salts include imide anion ((CF ₃ SO ₂ ) ₂ N ⁻ ,
(CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ ) or a fluoride anion (BF ₄ ⁻ , PF) containing at least one or more elements selected from boron (B), phosphorus (P) and sulfur (S)
^{_{6 -, CF 3 SO 3 -}} , C (CF 3 SO 2) 3 - and the like), salts with lithium ion. When the salt represented by the general formula (1) is used as the lithium salt in the electrolyte composition of the present invention, a salt represented by the general formula (1) other than the lithium salt and the lithium salt (for example, when Y is an organic compound) Cation)
May be used in combination. As the salt that can be used in combination with the lithium salt, in the general formula (1), Y represents the general formula (2-
Salts that are organic cations represented by any of a) to (2-c) are preferred. The content of the lithium salt (excluding the lithium salt represented by the general formula (1)) in the electrolyte composition of the present invention is 1% by mass or more based on the salt represented by the general formula (1). The content is preferably 70% by mass or less, more preferably 20% by mass or more and 50% by mass or less.

The electrolyte composition of the present invention can be used for a reaction solvent such as a chemical reaction and metal plating, a CCD (charge coupled device) camera, and various electrochemical batteries (so-called batteries). Among the batteries, the battery is preferably used for an electrolyte of a nonaqueous secondary battery (particularly, a lithium secondary battery) or a photoelectrochemical battery using the following semiconductor, and more preferably used for a photoelectrochemical battery.

[Photoelectrochemical Cell] The photoelectrochemical cell of the present invention utilizing the electrolyte composition of the present invention will be described below. The photoelectrochemical cell of the present invention has a charge transport layer containing the electrolyte composition, a photosensitive layer containing a semiconductor sensitized with a dye, and a counter electrode. It is designed to work with Since the charge transport layer contains the electrolyte composition of the present invention, the photoelectrochemical cell of the present invention has excellent photoelectric conversion performance and exhibits excellent durability with little deterioration in battery performance over time.

[1] Photoelectric Conversion Element FIG. 1 shows an example of a photoelectric conversion element applicable to the present invention. The photoelectric conversion element 10 includes a conductive layer 12, an undercoat layer 14,
The photosensitive layer 16, the charge transport layer 18, and the counter electrode conductive layer 20 are sequentially laminated. The photosensitive layer 16 includes the semiconductor layer 24 sensitized by the dye d and the charge transport material t. The semiconductor layer 24 is a porous layer made of semiconductor fine particles s, and voids are formed between the semiconductor fine particles s, and the charge transport material t has penetrated into the voids. The charge transport material t is composed of the same components as those used for the charge transport layer 18. Substrate 26 is located below conductive layer 12 and substrate 28 is located below counter electrode conductive layer 20.
Is arranged. The substrates 26 and 28 are for imparting strength to the photoelectric conversion element, and need not be provided. Also,
Boundary of each layer, for example, conductive layer 12 and photosensitive layer 16
At the boundary between the photoconductive layer 16 and the charge transport layer 18, the boundary between the charge transport layer 18 and the counter electrode conductive layer 20, etc., the components of each layer may be mutually diffused and mixed. Light may be incident on the photoelectric conversion element 10 from one or both sides, and the conductive layer 12 on the light incident side and the substrate 26 and / or
Alternatively, the counter electrode conductive layer 20 and the substrate 28 can be made of a material having light transmittance.

Next, the operation of the photoelectric conversion element 10 will be described. The case where the semiconductor fine particles s are n-type will be described. When light enters the photoelectric conversion element 10, the incident light reaches the photosensitive layer 16 and is absorbed by the dye d and the like.
An excited state dye d is generated. The excited dye d, etc.,
Pass high-energy electrons to the conduction band of the semiconductor particles s,
The substance itself becomes an oxidant. The electrons transferred to the conduction band reach the conductive layer 12 by the network of the semiconductor fine particles s.
Therefore, the conductive layer 12 has a negative potential with respect to the counter electrode conductive layer 20. In a mode in which the photoelectric conversion element 10 is used for a photovoltaic cell, when this photovoltaic cell is connected to an external circuit, the electrons in the conductive layer 12 reach the counter electrode conductive layer 20 while working in the external circuit. When the charge transporting material is an electrolyte, the electrons reduce the electrolyte component (for example, I ⁻ ), and the generated reductant (for example, I ₃ ⁻ ) reduces the oxidized form of the dye d to restore the original. By continuously irradiating light, a series of reactions occurs continuously, and electricity can be extracted.

Hereinafter, materials usable for each layer of the photoelectric conversion element and a method for forming the same will be described. In the following, when the term “conductive support” is used, only the conductive layer 12 is used.
In addition, the term “counter electrode” includes both the counter electrode conductive layer 20 alone and both the counter electrode conductive layer 20 and the substrate 26 optionally provided.

(A) Conductive Support The conductive support comprises (1) a single layer of a conductive layer or (2) two layers of a conductive layer and a substrate. In the case of (1), a material that maintains sufficient strength and sealing properties is used as the conductive layer. For example, a metal material (platinum, gold, silver, copper, zinc, titanium, aluminum, or the like) Alloy) can be used. In the case of (2), a substrate having a conductive layer containing a conductive agent on the photosensitive layer side can be used. Preferred conductive agents include metals (for example, platinum, gold, silver, copper, zinc, titanium, aluminum, indium and the like or alloys containing these), carbon, and conductive metal oxides (indium-tin composite oxide, tin oxide). And the like doped with fluorine or antimony). The thickness of the conductive layer is 0.02-
About 10 μm is preferable.

The lower the surface resistance of the conductive support, the better. The preferred range of the surface resistance is 50 Ω / □ or less, more preferably 20 Ω / □ or less.

When light is irradiated from the conductive support side, the conductive support is preferably substantially transparent.
Substantially transparent means that it is in the visible to near infrared region (400 to
(1,200 nm) in part or all of the light.
It means 0% or more, preferably 50% or more, and more preferably 80% or more. In particular, it is preferable that the transmittance in a wavelength region where the photosensitive layer has sensitivity is high.

As the transparent conductive support, it is preferable to form a transparent conductive layer made of a conductive metal oxide on the surface of a transparent substrate such as glass or plastic by coating or vapor deposition. Preferred as the transparent conductive layer is tin dioxide or indium-tin oxide (ITO) doped with fluorine or antimony. As the transparent substrate, a glass substrate such as soda glass which is advantageous in terms of cost and strength and alkali-free glass which is not affected by alkali elution, and a transparent polymer film can be used. As materials for the transparent polymer film, triacetyl cellulose (TAC), polyethylene terephthalate (PE)
T), polyethylene naphthalate (PEN), syndiotactic polysterene (SPS), polyphenylene sulfide (PPS), polycarbonate (PC), polyarylate (PAr), polysulfone (PSF), polyester sulfone (PES), polyimide ( P
I), polyetherimide (PEI), cyclic polyolefin, brominated phenoxy and the like. In order to secure sufficient transparency, the amount of the conductive metal oxide applied is 0.01 to 100 g per 1 m ² of a glass or plastic support.
It is preferred that

It is preferable to use a metal lead for the purpose of lowering the resistance of the transparent conductive support. The material of the metal lead is preferably a metal such as platinum, gold, nickel, titanium, aluminum, copper, or silver. It is preferable that the metal lead is provided on a transparent substrate by vapor deposition, sputtering, or the like, and a transparent conductive layer made of conductive tin oxide or an ITO film is provided thereon. The decrease in the amount of incident light due to the installation of metal leads is preferably 10
%, More preferably 1 to 5%.

(B) Photosensitive Layer The photosensitive layer has a function of absorbing light to separate electric charges and generate electrons and holes. The photosensitive layer includes a dye-sensitized semiconductor. In a dye-sensitized semiconductor, light absorption and thus generation of electrons and holes mainly occur in the dye, and the semiconductor plays a role of receiving and transmitting the electrons (or holes). The semiconductor used in the present invention is preferably an n-type semiconductor which gives an anode current by conducting electrons as carriers under photoexcitation.

(1) Semiconductor As the semiconductor, a simple semiconductor such as silicon or germanium, a III-V compound semiconductor, a metal chalcogenide (for example, an oxide, a sulfide, a selenide, or a composite thereof), or Compounds having a perovskite structure (eg, strontium titanate, calcium titanate, sodium titanate, barium titanate, potassium niobate, etc.) can be used.

As a preferred metal chalcogenide,
Tan, tin, zinc, iron, tungsten, zirconium,
Hafnium, strontium, indium, cerium,
Yttrium, lanthanum, vanadium, niobium, or
Oxide, cadmium, zinc, lead, silver, antimony
Of bismuth or bismuth sulfide, cadmium or lead
And cadmium telluride. Other compounds
Semiconductors such as zinc, gallium, indium, and cadmium
Phosphide such as gallium-arsenic or copper-indium
Selenide, copper-indium sulfide and the like
You. Furthermore, M _xO_yS_zOr M¹ _xM^Two _yO_z(M, M¹Passing
And M^TwoIs a metal element, O is an oxygen atom, x, y and
z is the number of combinations whose valence is neutral)
A thing can also be used preferably.

Preferred examples of the semiconductor used in the present invention include Si, TiO ₂ , SnO ₂ , Fe ₂ O ₃ , WO ₃ , Zn
O, Nb ₂ O ₅ , CdS, ZnS, PbS, Bi ₂ S ₃ , C
dSe, CdTe, SrTiO ₃ , GaP, InP, G
aAs, CuInS ₂ , CuInSe _2, etc., more preferably TiO ₂ , ZnO, SnO ₂ , Fe ₂ O ₃ , W
O ₃ , Nb ₂ O ₅ , CdS, PbS, CdSe, SrTi
O ₃ , InP, GaAs, CuInS ₂ or CuInSe
₂ , particularly preferably TiO ₂ or Nb ₂ O ₅ ,
Most preferably TiO _2. TiO ₂ is preferably TiO ₂ containing anatase 70%, especially TiO ₂ of preferably 100% anatase. It is also effective to dope a metal for the purpose of increasing electron conductivity in these semiconductors. The metal to be doped is preferably a divalent or trivalent metal. It is also effective to dope the semiconductor with a monovalent metal for the purpose of preventing a reverse current from flowing from the semiconductor to the charge transport layer.

The semiconductor used in the present invention may be a single crystal or polycrystal. However, from the viewpoints of production cost, securing of raw materials, energy payback time, etc., polycrystal is preferable, and a porous film made of semiconductor fine particles is particularly preferable. In addition, a part of the amorphous portion may be included.

The particle size of the semiconductor fine particles is generally on the order of nm to μm, but the average particle size of the primary particles obtained from the diameter when the projected area is converted into a circle is preferably from 5 to 200 nm, and from 8 to 200 nm. 100 nm is more preferred. The average particle size of the semiconductor fine particles (secondary particles) in the dispersion is 0.0
1-30 micrometers is preferable. Two or more kinds of fine particles having different particle size distributions may be mixed, and in this case, the average size of the small particles is preferably 25 nm or less, more preferably 10 nm or less. In order to improve the light capture rate by scattering the incident light, a large particle size, for example, 100 nm
As described above, it is also preferable to mix semiconductor particles of about 300 nm.

A mixture of two or more different types of semiconductor fine particles may be used. When two or more kinds of semiconductor fine particles are used as a mixture, one kind is preferably TiO ₂ , ZnO, Nb ₂ O ₅ or SrTiO ₃ . Another type is preferably SnO ₂ , Fe ₂ O ₃ , or WO ₃ . A more preferable combination is ZnO and Sn
Combinations of O ₂ , ZnO and WO ₃ or ZnO, SnO ₂ and WO _{3 and the} like can be given. When two or more kinds of semiconductor fine particles are used as a mixture, the respective particle diameters may be different. In particular, a combination in which the particle size of the semiconductor fine particles described in the first type is large and the semiconductor fine particles described in the second and subsequent types is small is preferable. Preferably, the combination is such that the particles having a large particle diameter are 100 nm or more and the particles having a small particle diameter are 15 nm or less.

As a method for producing semiconductor fine particles, there is a method described in "Sol-Gel Method Science" by Akio Sakuhana, Agne Shofusha (1998).
), A sol-gel method described in "Sol-gel method for thin film coating" (1995) of the Technical Information Association, etc.
Tadao Sugimoto, "Synthesis of Monodispersed Particles by New Synthesis Method Gel-Sol Method and Size Morphology Control," Materia, Vol. 35, No. 9
No., pp. 1012 to 1018 (1996). Further, a method of producing an oxide by hydrolyzing a chloride in an oxyhydrogen salt at a high temperature developed by Degussa is also preferable.

When the semiconductor fine particles are titanium oxide, any of the above-mentioned sol-gel method, gel-sol method, and high-temperature hydrolysis method in a chloride oxyhydrogen salt are preferable. Applied Technology "Gihodo Publishing (1997
) Can also be used.
Further, as a sol-gel method, Barbe et al., Journal of American Ceramic Society, No. 8
Volume 0, Issue 12, 3157-3171 (1997)
And the chemistry of Burnside et al.
Of Materials, Vol. 10, No. 9, 2419-2
The method described on page 425 is also preferred.

(2) Semiconductor Particle Layer The semiconductor is used, for example, in the form of a semiconductor particle layer formed on the conductive support. In order to coat the semiconductor fine particles on the conductive support, in addition to the method of applying a dispersion or colloid solution of the semiconductor fine particles on the conductive support, the above-described sol-gel method or the like can also be used. In consideration of mass production of photoelectric conversion elements, physical properties of semiconductor fine particle liquid, flexibility of a conductive support, and the like, a wet film forming method is relatively advantageous. As a wet film forming method, a coating method, a printing method, an electrolytic deposition method, and an electrodeposition method are representative. A method of oxidizing a metal, a method of depositing a metal solution in a liquid phase by ligand exchange (LPD method), a method of vapor deposition by sputtering or the like, a method of CVD, or a method of thermally decomposing a metal on a heated substrate. An SPD method in which an oxide precursor is sprayed to form a metal oxide can also be used.

As a method for preparing a dispersion of semiconductor fine particles, in addition to the above-described sol-gel method, a method of grinding with a mortar, a method of dispersing while pulverizing using a mill, or a method of synthesizing a semiconductor when synthesizing a semiconductor. A method of precipitating fine particles in the solution and using it as it is is exemplified.

Examples of the dispersion medium include water and various organic solvents (eg, methanol, ethanol, isopropyl alcohol, citronellol, terpineol, dichloromethane, acetone, acetonitrile, ethyl acetate, etc.). At the time of dispersion, a polymer such as polyethylene glycol, hydroxyethyl cellulose, carboxymethyl cellulose, a surfactant, an acid, a chelating agent, or the like may be used as a dispersing aid, if necessary. By changing the molecular weight of polyethylene glycol, it is possible to adjust the viscosity of the dispersion, to form a semiconductor layer that is difficult to peel off, and to control the porosity of the semiconductor layer. Therefore, it is preferable to add polyethylene glycol.

The application method includes a roller method and a dipping method as an application system, an air knife method and a blade method as a metering system.
8-4589, U.S. Pat. Nos. 2,681,294, 2,761,419, and 276.
For example, a slide hopper method, an extrusion method, a curtain method, and the like described in US Pat. As a general-purpose machine, a spin method or a spray method is also preferable. As the wet printing method, intaglio printing, rubber printing, screen printing, and the like are preferable, including three major printing methods of letterpress, offset and gravure. From these, a preferable film forming method is selected according to the liquid viscosity and the wet thickness.

The layer of semiconductor fine particles is not limited to a single layer, but a multi-layer coating of a dispersion of semiconductor fine particles having different particle diameters, or a coating layer containing semiconductor fine particles of different types (or different binders and additives) may be formed in multiple layers. It can also be applied. Multilayer coating is effective even when the film thickness is insufficient by one coating.

In general, as the thickness of the semiconductor fine particle layer (same as the thickness of the photosensitive layer) becomes larger, the amount of the supported dye per unit projected area increases, so that the light capture rate increases, but the diffusion distance of generated electrons increases. Therefore, the loss due to charge recombination also increases. Therefore, the preferable thickness of the semiconductor fine particle layer is 0.1 to 100 μm. When used in a photovoltaic cell, the thickness of the semiconductor fine particle layer is preferably 1 to 30 μm, and 2 to 25 μm.
μm is more preferred. The coating amount of the semiconductor fine particles per 1 m ² of the support is preferably 0.5 to 100 g, preferably 3 to 100 g.
-50 g is more preferred.

After applying the semiconductor fine particles on the conductive support, the semiconductor fine particles are brought into electronic contact with each other,
Heat treatment is preferably performed to improve the strength of the coating film and the adhesion to the support. A preferable heating temperature range is 40 ° C. or more and 700 ° C. or less, more preferably 1 ° C. or less.
It is not less than 00 ° C and not more than 600 ° C. The heating time is about 10 minutes to 10 hours. When a support having a low melting point or softening point such as a polymer film is used, high-temperature treatment is not preferable because it causes deterioration of the support. From the viewpoint of cost, the temperature is preferably as low as possible (for example, 50 ° C. to 350 ° C.). The temperature can be lowered by heat treatment in the presence of small semiconductor particles of 5 nm or less, mineral acid, metal oxide precursor, etc. In addition, irradiation of ultraviolet rays, infrared rays, microwaves, etc., electric field, and application of ultrasonic waves Can also be performed. At the same time, in order to remove unnecessary organic substances and the like, it is preferable to use a combination of heating, decompression, oxygen plasma treatment, pure water washing, solvent washing, gas washing and the like in addition to the above-mentioned irradiation and application.

After the heat treatment, for example, chemical plating using an aqueous solution of titanium tetrachloride may be performed to increase the surface area of the semiconductor fine particles, increase the purity near the semiconductor fine particles, and increase the efficiency of electron injection from the dye into the semiconductor fine particles. Electrochemical plating using an aqueous solution of titanium trichloride may be performed. In order to prevent a reverse current from flowing from the semiconductor fine particles to the charge transport layer, it is also effective to adsorb an organic substance having low electron conductivity other than the dye on the particle surface. As the organic substance to be adsorbed, a substance having a hydrophobic group is preferable.

The semiconductor fine particle layer preferably has a large surface area so that many dyes can be adsorbed. The surface area in a state where the layer of the semiconductor fine particles is applied on the support is preferably 10 times or more, more preferably 100 times or more with respect to the projected area. The upper limit is not particularly limited, but is usually about 1000 times.

(3) Dye The sensitizing dye used in the photosensitive layer may be any compound that can absorb semiconductors in the visible or near infrared region and can sensitize semiconductors. And a porphyrin dye or a phthalocyanine dye. In addition, two or more dyes can be used in combination or mixed in order to broaden the wavelength range of photoelectric conversion as much as possible and increase the conversion efficiency. In this case, the pigments to be used or mixed and the ratio thereof can be selected so as to match the wavelength range and the intensity distribution of the target light source.

Such a dye is appropriately bonded to a surface of the semiconductor fine particles by a suitable binding group (interlocki).
ng group). Preferred linking groups include COOH groups, OH groups, SO ₃ H groups,
Acidic groups such as -P (O) (OH) ₂ or -OP (O) (OH) ₂ groups, or π-conducting chelation such as oximes, dioximes, hydroxyquinolines, salicylates or α-ketoenolates. Groups. Above all, a COOH group, -P (O) (OH) ₂ group or -OP
(O) (OH) ₂ groups are particularly preferred. These groups may form a salt with an alkali metal or the like, or may form an intramolecular salt. In the case of a polymethine dye, when a methine chain contains an acidic group such as a case where a squarylium ring or a croconium ring is formed, the methine chain may have this portion as a bonding group.

Hereinafter, preferred sensitizing dyes for use in the photosensitive layer will be specifically described. (A) Organic metal complex dye When the dye is a metal complex dye, a metal phthalocyanine dye, a metal porphyrin dye or a ruthenium complex dye is preferable, and a ruthenium complex dye is particularly preferable. Ruthenium complex dyes include, for example, US Pat. No. 4,927,721.
Nos. 4,684,537, 5,084,365, and 53
No. 50644, No. 5463057, No. 5525440
And Japanese Patent Application Laid-Open No. 7-249790, Japanese Patent Application Laid-Open No. 10-504512, and World Patent 98/50393.
And complex dyes described in JP-A-2000-26487.

When the dye is a ruthenium complex dye, a ruthenium complex dye represented by the following general formula (5) is preferable. (A ¹ ) _t Ru (Ba) _u (Bb) _v (Bc) _{w In the} general formula (5), A ¹ represents a mono- or bidentate ligand. A ¹ is Cl, SCN, H ₂ O, Br, I, CN, NC
It is preferably a ligand selected from the group consisting of O, SeCN, β-diketones, oxalic acid and derivatives of dithiocarbamic acid. when t is 2 or more, 2 or more of A ¹ may be the same or different. In the general formula (5), B-
a, Bb and Bc are each independently the following formula (B-
1) represents a ligand represented by any of (B-10). t represents an integer of any of 0 to 3, and u, v and w
Each represents 0 or 1, and is appropriately combined depending on the kind of the ligand such that the ruthenium complex represented by the general formula (5) becomes a six-coordinate complex.

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In the above formulas (B-1) to (B-10), R _a
Represents a hydrogen atom or a substituent; examples of the substituent include a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, Examples thereof include a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an acidic group (these acidic groups may form a salt) or a chelating group. The alkyl portion of the alkyl group and the aralkyl group may be linear or branched. Further, the aryl group and the aryl part of the aralkyl group may be monocyclic or polycyclic (condensed ring, ring assembly). In the general formula (5), Ba, Bb and Bc may be the same or different.

Preferred specific examples of the organometallic complex dyes (exemplary compounds R-1 to R-17) are shown below, but the dyes used in the present invention are not limited to the following specific examples.

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(B) Methine Dye Preferred methine dyes used in the present invention are polymethine dyes such as cyanine dyes, merocyanine dyes, and squarylium dyes. Examples of the polymethine dye preferably used in the present invention include, for example, JP-A-11-35836.
JP-A-11-67285, JP-A-11-8691
6, JP-A-11-97725, JP-A-11-158
395, JP-A-11-163378, JP-A-11-163
214730, JP-A-11-214731, JP-A-11-238905, JP-A-2000-26487,
European Patent Nos. 892411, 911841 and 99
The dyes described in each of the specifications of No. 1092 can be used. Specific examples of preferred methine dyes are shown below.

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(4) Adsorption of Dye on Semiconductor Fine Particles The dye is adsorbed on the semiconductor fine particles by immersing a conductive support having a well-dried semiconductor fine particle layer in a dye solution, or by dissolving the dye solution in a semiconductor solution. A method of applying to the fine particle layer can be used. In the former case, a dipping method, a dipping method, a roller method, an air knife method, or the like can be used. In the case of the immersion method, the dye may be adsorbed at room temperature or may be heated and refluxed as described in JP-A-7-249790. Examples of the latter coating method include a wire bar method, a slide hopper method, an extrusion method, a curtain method, a spin method, and a spray method. Preferred solvents for dissolving the dye include, for example, alcohols (methanol, ethanol, t-butanol, benzyl alcohol, etc.), nitriles (acetonitrile, propionitrile, 3-methoxypropionitrile, etc.),
Nitromethane, halogenated hydrocarbons (dichloromethane,
Dichloroethane, chloroform, chlorobenzene, etc.),
Ethers (eg, diethyl ether, tetrahydrofuran), dimethyl sulfoxide, amides (eg, N, N-dimethylformamide, N, N-dimethylacetamide),
N-methylpyrrolidone, 1,3-dimethylimidazolidinone, 3-methyloxazolidinone, esters (ethyl acetate, butyl acetate, etc.), carbonates (diethyl carbonate, ethylene carbonate, propylene carbonate, etc.), ketones (acetone, 2-butanone, cyclohexanone, etc.), hydrocarbons (hexane, petroleum ether, benzene, toluene, etc.)
And a mixed solvent thereof.

The total amount of the dye adsorbed is 0.01 to 100 mmol per unit surface area (1 m ² ) of the porous semiconductor electrode substrate.
l is preferred. The amount of the dye adsorbed on the semiconductor fine particles is preferably in the range of 0.01 to 1 mmol per 1 g of the semiconductor fine particles. By setting the dye adsorption amount in the above range, a sufficient sensitizing effect in the semiconductor can be obtained. On the other hand, if the amount of the dye is too small, the sensitizing effect becomes insufficient, and if the amount of the dye is too large, the dye not adhering to the semiconductor floats and causes a reduction in the sensitizing effect. In order to increase the amount of the dye adsorbed, it is preferable to perform a heat treatment before the adsorption. After the heat treatment, in order to avoid the adsorption of water on the surface of the semiconductor fine particles, it is preferable to quickly perform the dye adsorption operation at a temperature of the semiconductor electrode substrate of 60 to 150 ° C. without returning to normal temperature. For the purpose of reducing the interaction such as aggregation between the dyes, a colorless compound may be added to the dyes and co-adsorbed to the semiconductor fine particles. Compounds effective for this purpose are compounds having surface active properties and structures, and include, for example, steroid compounds having a carboxyl group (for example, chenodeoxycholic acid) and sulfonates such as those described below.

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It is preferable to remove the unadsorbed dye by washing immediately after the adsorption. It is preferable to perform cleaning with a polar solvent such as acetonitrile and an organic solvent such as an alcohol solvent using a wet cleaning tank. After adsorbing the dye, the surface of the semiconductor fine particles may be treated with an amine or a quaternary salt. Preferred amines include pyridine, 4-t-
Butyl pyridine and polyvinyl pyridine and the like,
Preferred quaternary salts include tetrobutylammonium iodide and tetrahexylammonium iodide. When these are liquids, they may be used as they are or may be used by dissolving them in an organic solvent.

(C) Charge Transport Layer The charge transport layer is a layer containing a charge transport material having a function of replenishing electrons to the oxidized dye. Examples of typical charge transporting materials that can be used for the charge transporting layer include (i) a solution in which redox pair ions are dissolved (electrolyte solution) and a redox pair solution as a polymer matrix as an ion transporting material. And a so-called gel electrolyte impregnated in the gel, a molten salt electrolyte containing a redox counter ion, and a solid electrolyte. In addition to the charge transporting material involving ions, an electron transporting material or a hole transporting material may be used as (ii) a charge transporting material involving carrier movement in a solid. In the present invention, the electrolyte composition of the present invention is used for the charge transport layer, but other charge transport materials described above can be used in combination.

(1) Formation of the charge transport layer Regarding the method of forming the charge transport layer, two methods can be considered. One is a method in which a counter electrode is first stuck on the photosensitive layer, and a liquid charge transport layer is sandwiched between the gaps. The other is a method in which a charge transport layer is provided directly on the photosensitive layer, and a counter electrode is subsequently provided.

In the former case, as a method for sandwiching the charge transport layer, a normal pressure process utilizing a capillary phenomenon due to immersion or the like,
Alternatively, a vacuum process in which the gas phase in the gap is replaced with a liquid phase at a pressure lower than normal pressure can be used.

In the latter case, the wet type charge transport layer is provided with a counter electrode in an undried state to take measures to prevent liquid leakage at the edge. Further, in the case of a gel electrolyte, there is a method of applying it by a wet method and solidifying it by a method such as polymerization. In this case, a counter electrode can be provided after drying and immobilization. As a method for applying a wet organic hole transport material or a gel electrolyte in addition to the electrolytic solution, a method similar to the method for applying the semiconductor fine particle layer or the dye described above can be used.

(D) Counter Electrode Like the above-mentioned conductive support, the counter electrode may have a single-layer structure of a counter electrode conductive layer made of a conductive material, or may be composed of a counter electrode conductive layer and a support substrate. As the conductive material used for the counter electrode conductive layer, a metal (for example, platinum, gold, silver, copper, aluminum, magnesium, indium, or the like), carbon, or a conductive metal oxide (indium-tin composite oxide, fluorine-doped tin oxide, Etc.). Among them, platinum,
Gold, silver, copper, aluminum, and magnesium can be preferably used as the counter electrode layer. A preferred example of the support substrate for the counter electrode is glass or plastic, to which the above-described conductive agent is applied or deposited. The thickness of the counter electrode conductive layer is not particularly limited, but is preferably 3 nm to 10 μm. The lower the surface resistance of the counter electrode layer, the better. The preferable range of the surface resistance is 50 Ω / □ or less, more preferably 20 Ω / □ or less.

Since the light may be irradiated from one or both of the conductive support and the counter electrode, in order for the light to reach the photosensitive layer, at least one of the conductive support and the counter electrode is substantially transparent. I just need. From the viewpoint of improving the power generation efficiency, it is preferable that the conductive support is made transparent and light is incident from the conductive support side. In this case, the counter electrode preferably has a property of reflecting light. As such a counter electrode, glass or plastic on which a metal or a conductive oxide is deposited, or a metal thin film can be used.

As the counter electrode, a conductive material may be applied directly onto the charge transport layer, plated or vapor-deposited (PVD, CVD), or may be attached to the conductive layer side of the substrate having the conductive layer. As in the case of the conductive support, particularly when the counter electrode is transparent, it is preferable to use a metal lead for the purpose of reducing the resistance of the counter electrode. Note that the preferable material and installation method of the metal lead, the decrease in the amount of incident light due to the installation of the metal lead, and the like are the same as those of the conductive support.

(E) Other Layers In order to prevent a short circuit between the counter electrode and the conductive support, a dense semiconductor thin film layer may be previously coated between the conductive support and the photosensitive layer as an undercoat layer. It is particularly effective when an electron transporting material or a hole transporting material is used for the charge transporting layer. TiO ₂ , SnO ₂ , F
_{e 2 O 3, WO 3,} ZnO, a Nb ₂ O _5, more preferably from TiO _2. The undercoat layer is made of, for example, Elect.
rochim. Acta 40, 643-652
In addition to the spray pyrolysis method described in (1995), coating can be performed by a sputtering method or the like. The preferred thickness of the undercoat layer is 5 to 1000 nm or less.
0-500 nm is more preferable.

A functional layer such as a protective layer or an anti-reflection layer may be provided on the outer surface of one or both of the conductive support serving as an electrode and the counter electrode, between the conductive layer and the substrate, or in the middle of the substrate. Good. For forming these functional layers, a coating method, a vapor deposition method, a sticking method or the like can be used depending on the material.

In the photoelectrochemical cell of the present invention, it is preferable to seal the side surfaces with a polymer, an adhesive or the like in order to prevent the above-mentioned components from deteriorating and the contents from volatilizing.

The photoelectrochemical cell of the present invention has basically the same configuration as that of the photoelectric conversion element. The photoelectric conversion element is connected to an external circuit via a lead wire or the like so that work is performed in the external circuit. It is what was constituted. As the external circuit itself connected to the conductive support and the counter electrode via a lead wire or the like, a known circuit can be used. Further, the photoelectrochemical cell of the present invention can have a module structure basically similar to that of a conventional solar cell module. The solar cell module generally has a structure in which cells are formed on a support substrate such as a metal and a ceramic, and the cells are covered with a filling resin or protective glass or the like, and light is taken in from the opposite side of the support substrate. It is also possible to adopt a structure in which a transparent material such as tempered glass is used for the support substrate, and a cell is formed thereon to take in light from the transparent support substrate side. Specifically, a superstrate type, a substrate type, a module structure called a potting type, a substrate-integrated module structure used in an amorphous silicon solar cell, and the like are known, and the photoelectrochemical cell of the present invention is also used and used. These module structures can be appropriately selected depending on the place and environment. Specifically, Japanese Patent Application No. 11-8457
It is preferable to apply the structure and embodiment described in the specification of the above item.

[Non-Aqueous Secondary Battery] The non-aqueous secondary battery of the present invention using the electrolyte composition of the present invention will be described below. The non-aqueous secondary battery of the present invention is characterized by containing the electrolyte composition of the present invention. Since the non-aqueous secondary battery of the present invention contains the electrolyte composition of the present invention, it exhibits excellent cyclability without greatly reducing the capacity.

When the electrolyte composition of the present invention is used in a non-aqueous secondary battery, the positive electrode active material may be a transition metal oxide capable of reversibly inserting and releasing lithium ions, but a lithium-containing transition metal oxide is particularly preferred. . Preferred lithium-containing transition metal oxide cathode active materials used in the present invention include lithium-containing Ti, V, Cr, Mn, Fe, Co,
An oxide containing Ni, Cu, Mo, and W may be used. Alkali metals other than lithium (first (IA) of the periodic table)
Group II, Group IIA) and / or Al, G
a, In, Ge, Sn, Pb, Sb, Bi, Si, P,
B or the like may be mixed. The mixing amount is 0 with respect to the transition metal.
~ 30 mol% is preferred.

More preferred lithium-containing transition metal oxide positive electrode active materials used in the present invention include lithium compounds / transition metal compounds (where transition metals are Ti, V,
It is preferable to synthesize them by mixing them so that the total molar ratio of Cr, Mn, Fe, Co, Ni, Mo and W) is 0.3 to 2.2.

Particularly preferred lithium-containing transition metal oxide cathode active materials used in the present invention include lithium compounds / transition metal compounds (where transition metals are V, Cr,
At least one selected from Mn, Fe, Co, Ni)
It is preferable to mix and synthesize so that the total molar ratio of is 0.3 to 2.2.

A particularly preferred lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _g M ³ O ₂ (M ³ is C
at least one selected from o, Ni, Fe and Mn, g = 0
Material including 1.2) or ^{_{Li h M 4 2 O 4 (}} M 4 is M
n, h = 0 to 2) and having a spinel structure, wherein M ³ and M ⁴ include Al, G
a, In, Ge, Sn, Pb, Sb, Bi, Si, P or B may be mixed. The mixing amount is preferably 0 to 30 mol% based on the transition metal.

The most preferred lithium-containing transition metal oxide cathode active material used in the present invention is Li _g Co
O ₂ , Li _g NiO ₂ , Li _g MnO ₂ , Li _g Co _j Ni
_(1-j) O ₂ , Li _h Mn ₂ O ₄ (where g = 0.2-1.
2, j = 0.1 to 0.9). Here, the above-mentioned g value is a value before the start of charging and discharging, and increases or decreases due to charging and discharging.

The positive electrode active material can be synthesized by a known method such as a method of mixing and firing a lithium compound and a transition metal compound and a solution reaction, but the firing method is particularly preferable.

The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.1 to 50 μm. The specific surface area is not particularly limited, but is preferably 0.01 to 50 m ² / g by the BET method. In addition, the positive electrode active material 5
The pH of the supernatant when g is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.

To obtain a predetermined particle size, a well-known pulverizer or classifier can be used. For example, a mortar, a ball mill, a vibrating ball mill, a vibrating mill, a satellite ball mill, a planetary ball mill, a swirling air jet mill, a sieve, and the like are used. The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

One of the negative electrode active materials used in the present invention is:
It is a carbonaceous material that can store and release lithium. The carbonaceous material is a material substantially composed of carbon. For example,
Examples of the carbonaceous material include artificial graphite such as petroleum pitch, natural graphite, vapor-grown graphite, and various synthetic resins such as PAN-based resin and furfuryl alcohol resin. Further, PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA
Various types of carbon fibers such as base carbon fibers, lignin carbon fibers, glassy carbon fibers, and activated carbon fibers, mesophase microspheres, graphite whiskers, and flat graphite can also be mentioned. These carbonaceous materials can be classified into non-graphitizable carbon materials and graphite-based carbon materials according to the degree of graphitization. Further, the carbonaceous material preferably has a plane spacing, a density, and a crystallite size described in JP-A-62-22066, JP-A-2-6856, and JP-A-3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844, graphite having a coating layer described in JP-A-6-4516, or the like is used. You can also.

Other examples of the negative electrode active material usable in the present invention include oxides and / or chalcogenides.

Particularly, amorphous oxides and / or chalcogenides are preferable. The term “amorphous” used herein refers to a substance having a broad scattering band having an apex in a range of 20 ° to 40 ° in 2θ value by X-ray diffraction using CuKα ray, May have. Preferably 40 in 2θ value
The strongest intensity of the crystalline diffraction lines observed at not less than 70 ° is not more than 100 times the intensity of the diffraction line at the apex of the broad scattering band observed at not less than 20 ° and not more than 40 ° in 2θ value. It is preferably 5 times or less, and particularly preferably has no crystalline diffraction line.

In the present invention, among them, an amorphous oxide of a metalloid element and / or a chalcogenide are preferable, and an element of group 13 (IIIB) to group 15 (VB), Al, G
An oxide or chalcogenide consisting of a, Si, Sn, Ge, Pb, Sb, Bi alone or a combination of two or more thereof is selected.

For example, Ga_TwoO_Three, SiO, GeO, Sn
O, SnO_Two, PbO, PbO_Two, Pb_TwoO_Three, Pb_TwoO_Four,
Pb_ThreeO_Four, Sb_TwoO_Three, Sb_TwoO_Four, Sb_TwoO_Five, Bi_TwoO_Three,
Bi _TwoO_Four, SnSiO_Three, GeS, SnS, SnS_Two, P
bS, PbS_Two, Sb_TwoS_Three, Sb_TwoS_Five, SnSiS_ThreeSuch
Is preferred. These are complex acids with lithium oxide.
Compound, for example, Li_TwoSnO_TwoIt may be.

In the negative electrode material of the present invention, Sn, Si,
An amorphous oxide centered on Ge is more preferable, and among them, an amorphous oxide represented by the following general formula (6) is preferable. In the general formula _{^{(6) SnM 1 d M 2}} e O f formula, M ¹ is, Al, B, at least one element selected from P and Ge, M ² is the Periodic Table 1 (IA) group elements, Represents at least one or more elements selected from Group 2 (IIA), Group 3 (IIIA) and halogen elements, d is a number from 0.2 to 2 and e is 0.01
0.2 <d + e <2, where f is 1 or more and 6 or less
The following numbers are shown.

Examples of the amorphous oxide mainly composed of Sn include the following compounds, but the present invention is not limited to these compounds. _{C- 1 SnSiO 3 C- 2 Sn 0.8} Al 0.2 B 0.3 P 0.2 Si 0.5 O 3.6 C- 3 SnAl 0.4 B 0.5 Cs 0.1 P 0.5 O 3.65 C- 4 SnAl 0.4 B 0.5 Mg 0.1 P 0.5 O 3.7 C- 5 SnAl _0.4 B _0.4 Ba _0.08 P _0.4 O _3.28 C-6 SnAl _0.4 B _0.5 Ba _0.08 Mg _0.08 P _0.3
O _3.26 C-7 SnAl _0.1 B _0.2 Ca _0.1 P _0.1 Si _0.5 O
_3.1 C-8 SnAl _0.2 B _0.4 Si _0.4 O _2.7 C-9 SnAl _0.2 B _0.1 Mg _0.1 P _0.1 Si _0.5 O
_{2.6 C-10 SnAl 0.3 B 0.4} P 0.2 Si 0.5 O 3.55 C-11 SnAl 0.3 B 0.4 P 0.5 Si 0.5 O 4.3 C-12 SnAl 0.1 B 0.1 P 0.3 Si 0.6 O 3.25 C-13 SnAl 0.1 B 0.1 Ba 0.2 P _0.1 Si _0.6 O
_2.95 C-14 SnAl _0.1 B _0.1 Ca _0.2 P _0.1 Si _0.6 O
_2.95 C-15 SnAl _0.4 B _0.2 Mg _0.1 Si _0.6 O _3.2 C-16 SnAl _0.1 B _0.3 P _0.1 Si _0.5 O _3.05 C-17 SnB _0.1 K _0.5 P _0.1 SiO _3.65 C-18 SnB _0.5 F _0.1 Mg _0.1 P _0.5 O _3.05 The amorphous oxide and / or chalcogenite of the present invention is
Either a firing method or a solution method can be employed, but the firing method is more preferable. In the firing method, it is preferable that the oxide, chalcogenite or compound of the corresponding element is mixed well and then fired to obtain an amorphous oxide and / or chalcogenite. These can be produced by a known method.

The average particle size of the negative electrode material used in the present invention is preferably 0.1 to 60 μm. In order to obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibration ball mill, a satellite ball mill, a planetary ball mill, a swirling air jet mill, a sieve, and the like are used. At the time of pulverization, wet pulverization in the presence of water or an organic solvent such as methanol can also be performed as necessary. Classification is preferably performed to obtain a desired particle size. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be performed both in a dry type and a wet type.

As the negative electrode material which can be used in combination with the amorphous oxide negative electrode material mainly composed of Sn, Si and Ge of the present invention, lithium ion or lithium metal is used.
Examples include a carbon material that can be released, lithium, a lithium alloy, and a metal that can be alloyed with lithium.

An aprotic organic solvent is added to the electrode mixture of the present invention in addition to a conductive agent, a binder and a filler.

[0124] The above-mentioned conductive agent may be used in a battery comprising:
Any material may be used as long as it does not cause a chemical change. Usually, natural graphite (scale graphite, flaky graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber and metal powder (copper, nickel, aluminum, silver (JP-A-63-63)) 148, 55
4)), metal fibers or polyphenylene derivatives (JP-A-59-20971).
It can be included as a species or a mixture thereof. A combination of graphite and acetylene black is particularly preferred. The addition amount is preferably from 1 to 50% by mass, particularly preferably from 2 to 30% by mass. 2-15 mass% for carbon and graphite
Is particularly preferred.

In the present invention, a binder for holding the electrode mixture can be used. Examples of the binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Preferred binders include starch, carboxymethyl cellulose, cellulose, diacetyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, polyacrylic acid, sodium polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone Water-soluble polymers such as polyacrylonitrile, polyacrylamide, polyhydroxy (meth) acrylate, styrene-maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, Vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, Ethylene-propylene-diene terpolymer (EPDM), sulfonated EPD
M, polyvinyl acetal resin, (meth) acrylate copolymer containing (meth) acrylate such as methyl methacrylate, 2-ethylhexyl acrylate, etc., (meth) acrylate-acrylonitrile copolymer, vinyl acetate, etc. A polyvinyl ester copolymer containing a vinyl ester, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene, neoprene (registered trademark) rubber, fluororubber, polyethylene oxide, polyester polyurethane resin, polyether polyurethane resin, Emulsions (latex) or suspensions of polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin and the like can be given. In particular, polyacrylate latex, carboxymethyl cellulose, polytetrafluoroethylene, and polyvinylidene fluoride are exemplified. These binders can be used alone or in combination. If the amount of the binder is small, the holding power and cohesive strength of the electrode mixture are weak. If it is too large, the electrode volume increases, and the capacity per unit volume or unit mass of the electrode decreases. For this reason, the amount of the binder added is 1 to
It is preferably 30% by mass, and particularly preferably 2 to 10% by mass.

As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. Usually, fibers such as olefin polymers such as polypropylene and polyethylene, glass and carbon are used. The amount of the filler added is not particularly limited, but is preferably 0 to 30% by mass.

The electrolyte composition of the present invention can be used in combination with a separator to ensure safety.
It is necessary that the separator used together to ensure safety has a function of closing the above gap at 80 ° C. or higher to increase the resistance and cut off the current.
It is preferably 80 ° C. or lower.

The shape of the pores of the separator is usually circular or elliptical, and the size is 0.05 μm to 30 μm.
1 μm to 20 μm is preferred. Further, as in the case of making by a stretching method or a phase separation method, the holes may be rod-shaped or amorphous. The ratio occupied by these gaps, that is, the porosity is 20
% To 90%, preferably 35% to 80%.

These separators are made of polyethylene,
It may be a single material such as polypropylene or a composite material of two or more. In particular, those obtained by laminating two or more kinds of microporous films having different pore diameters, porosity, and pore closing temperatures are particularly preferable.

As the positive / negative current collector, an electron conductor which does not cause a chemical change in the constructed battery is used.

As the current collector of the positive electrode, in addition to aluminum, stainless steel, nickel, titanium and the like, those obtained by treating the surface of aluminum or stainless steel with carbon, nickel, titanium or silver are preferable. Aluminum and aluminum alloy.

As the current collector of the negative electrode, copper, stainless steel, nickel, and titanium are preferable, and copper or a copper alloy is particularly preferable.

The shape of the current collector is usually a film sheet, but a net, a punched material, a lath, a porous material, a foam, a molded product of a fiber group, and the like can also be used. . The thickness is not particularly limited, but is 1 to 500
μm. It is also desirable that the surface of the current collector be made uneven by surface treatment.

The shape of the battery can be applied to any of sheets, corners, cylinders and the like. The mixture of the positive electrode active material and the negative electrode material is applied (coated) on the current collector, dried and compressed,
Mainly used. As a coating method, for example, a reverse roll method, a direct roll method, a blade method, a knife method, an extrusion method, a curtain method, a gravure method,
Bar method, dip method and squeeze method can be mentioned. Among them, a blade method, a knife method and an extrusion method are preferred. The coating is preferably performed at a speed of 0.1 to 100 m / min. At this time, by selecting the above coating method in accordance with the solution physical properties and drying properties of the mixture, a good surface state of the coated layer can be obtained. The coating may be performed on one side at a time or on both sides simultaneously.

The application may be continuous, intermittent, or striped. The thickness, length and width of the coating layer are determined by the shape and size of the battery, but the thickness of the coating layer on one side is
In a compressed state after drying, the thickness is preferably 1 to 2000 μm.

The method for drying and dehydrating the electrode sheet coating material is as follows.
Hot air, vacuum, infrared rays, far-infrared rays, electron beams and low-humidity air can be used alone or in combination. The drying temperature is preferably in the range of 80 to 350 ° C, particularly 100 to 350 ° C.
A range of 250 ° C. is preferred. The water content is 20
It is preferably at most 00 ppm, and more preferably at most 500 ppm for each of the positive electrode mixture, the negative electrode mixture and the electrolyte. As a method for pressing the sheet, a method generally used can be used, but a calendar press method is particularly preferable. The pressing pressure is not particularly limited, but is 0.2 to 3 t.
/ Cm ² is preferred. The press speed of the calender press method is preferably 0.1 to 50 m / min, and the press temperature is room temperature to
200 ° C. is preferred. The ratio of the negative electrode sheet width to the positive electrode sheet is preferably 0.9 to 1.1, and more preferably 0.95 to 1.0.
Is particularly preferred. The content ratio between the positive electrode active material and the negative electrode material is
It depends on the compound type and the mixture formulation.

After the positive and negative electrode sheets are overlapped with a separator interposed therebetween, they are directly processed into a sheet battery or folded and inserted into a rectangular can, and the can and the sheet are electrically connected. A prismatic battery is formed by injecting the electrolyte composition of the present invention and using a sealing plate. Also, after the positive and negative electrode sheets are overlapped and wound via a separator, inserted into a cylindrical can, and the can and sheet are electrically connected,
The electrolyte composition of the present invention is injected, and a cylinder battery is formed using a sealing plate. At this time, a safety valve can be used as a sealing plate. In addition to the safety valve, various conventionally known safety elements may be provided. For example, a fuse, a bimetal, a PTC element, or the like is used as the overcurrent prevention element.

In addition to the safety valve, as a countermeasure against the rise in the internal pressure of the battery can, a method of making a cut in the battery can, a method of cracking a gasket, a method of cracking a sealing plate, or a method of cutting a lead plate can be used. Further, the charger may be provided with a protection circuit incorporating measures for overcharging or overdischarging, or may be connected independently.

As a countermeasure against overcharging, a method of interrupting the current by increasing the internal pressure of the battery can be provided. At this time, a compound for increasing the internal pressure can be contained in the mixture or the electrolyte. Examples of compounds used to increase the internal pressure include Li ₂ CO ₃ , LiHCO ₃ , and Na ₂ CO ₃ .
₃ , carbonates such as NaHCO ₃ , CaCO ₃ , and MgCO ₃ .

For the can or the lead plate, a metal or alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, and aluminum or alloys thereof are used.

As a method for welding the cap, the can, the sheet, and the lead plate, known methods (eg, DC or AC electric welding, laser welding, ultrasonic welding) can be used. A conventionally known compound or mixture such as asphalt can be used as the sealing agent for closing.

The use of the non-aqueous secondary battery of the present invention is not particularly limited. For example, when the non-aqueous secondary battery is mounted on an electronic device, it is used in a notebook personal computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, cordless phone handset. ,
Pager, handy terminal, mobile fax,
Portable copy, portable printer, headphone stereo,
Video movies, LCD TVs, handy cleaners,
Portable CD, mini disk, electric shaver, transceiver, electronic organizer, calculator, memory card, portable tape recorder, radio, backup power supply, memory card, and the like. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game machines, road conditioners, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder fir machines, etc.). Furthermore, it can be used for various military purposes and space applications. Further, it can be combined with a solar cell.

[0143]

The present invention will be specifically described below with reference to examples. Example 1 Synthesis of Compound

[0144]

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1. Synthesis Example of Exemplified Compound F-5 1-1. Synthesis of Intermediate M-2 M-1 (53.5 g, 300 mmol) was dissolved in methylene chloride (150 ml), and thionyl chloride (28 ml, 3
80 mmol) / methylene chloride (50 ml) solution was added, and the mixture was heated under reflux for 4 hours. After cooling, water (30 ml) was added, and the mixture was extracted with methylene chloride.
4 g) were obtained.

1-2. Synthesis of Intermediate M-3 Trifluorosulfonamide (14.9 g, 100 mm
ol) in acetonitrile (200 ml) / triethylamine (28 ml, 200 mmol), and
A solution of M-2 (19.7 g, 100 mmol) / acetonitrile (50 ml) was added dropwise. After reacting at room temperature for 1 hour, the reaction solution was neutralized with a 1N-HCl aqueous solution and extracted with methylene chloride. The extract was dried over magnesium sulfate, concentrated, and purified by column to obtain 14 g of M-3.

1-3. Synthesis of F-5 M-3 (5 g, 16.2 mmol) obtained above was dissolved in tetrahydrofuran (30 ml), and LiOH (38
8 mg, 16.2 mmol) / water (5 ml) solution was added. The reaction mixture was concentrated and tetrahydrofuran (20
ml) was added, and the insolubles were filtered off, further concentrated, and dried under reduced pressure (60 ° C., 1 mmHg) to obtain the desired F-5 (5 g) as an oil. The structure was confirmed by 1H-NMR.

[0148] 2. Synthesis Example of Exemplified Compound F-6 1-ethyl-3-methylimidazolium iodide (2.
4 g, 10 mmol) was dissolved in methylene chloride (20 ml) / water (20 ml), and F-5 (3.15 g, 10 m
mol) was added and stirred. Separate the methylene chloride phase,
After concentration, the residue was purified by silica gel column chromatography.
(4.2 g) was obtained as a colorless oil.

Example 2 Photoelectrochemical cell 2-1. Preparation of Titanium Dioxide Dispersion Inside Volume Teflon Coated Inside 2
In a 00 ml stainless steel vessel, 15 g of titanium dioxide (Degussa P-25, Nippon Aerosil Co., Ltd.), 45 g of water, and a dispersant (Triton X, manufactured by Aldrich)
-100) of 1 g and zirconia beads having a diameter of 0.5 mm (manufactured by Nikkato Corporation) of 30 g were dispersed in a sand grinder mill (manufactured by Imex Corporation) at 1500 rpm for 2 hours. The zirconia beads were removed by filtration from the dispersion. The average particle size of the titanium dioxide in this case is 2.5
μm. The particle size at this time was measured with a master sizer manufactured by MALVERN.

2-2. Preparation of TiO ₂ electrode (electrode A) adsorbing dyes Conductive glass coated with fluorine-doped tin oxide (TCO glass-U manufactured by Asahi Glass Co., Ltd., 20 mm × 20 m
m), the above dispersion was applied to the conductive surface side using a glass rod. At this time, an adhesive tape was stretched on a part (3 mm from the end) on the conductive surface side to form a spacer, and glass was lined up so that the adhesive tape came to both ends and applied eight at a time. After application, peel off the adhesive tape,
Air dried for 1 day at room temperature. Next, this glass was placed in an electric furnace (muffle furnace FP-32 type manufactured by Yamato Scientific Co., Ltd.) and heated at 450 ° C.
For 30 minutes. After taking out the glass and cooling, an ethanol solution of the dye R-1 (3 × 10 ⁻⁴ mol /
Liter) for 3 hours. After immersing the dyed glass in 4-tert-butylpyridine for 15 minutes,
It was washed with ethanol and dried naturally. The thickness of the photosensitive layer thus obtained was 10 μm, and the coating amount of the semiconductor fine particles was 20 g / m ² . The surface resistance of the conductive glass was about 30Ω / □.

2-3. Preparation of Photoelectrochemical Cell A color sensitized TiO ₂ electrode substrate (1 cm × 1 cm) prepared as described above was placed on a salt represented by the general formula (1) shown in Table 1 or a salt for a comparative example. An acetonitrile solution of a salt-containing electrolyte composition (E-102 to E-112) (acetonitrile has the same mass as the composition) is applied, and
Acetonitrile was distilled off at ° C. under reduced pressure while infiltrating the TiO ₂ electrode. Further, depending on the electrolyte, after polymerization was performed under the conditions shown in Table 1, a platinum-evaporated glass of the same size was overlaid on these electrodes to obtain photoelectrochemical cells (samples P-102 to 112) (Table 1). ). In addition, an electrolyte solution using a solvent (E-101 in Table 1) was applied to the same dye-sensitized TiO ₂ electrode substrate (2 cm × 2 cm) as described above.
After overlapping with a platinum-deposited glass having the same size as the electrode, an electrolytic solution was impregnated into the gap between the two glasses by utilizing a capillary phenomenon, thereby producing a photoelectrochemical cell (sample P-101).

According to this example, a photoelectrochemical cell was prepared in which conductive glass (a conductive agent layer was provided on glass), a TiO ₂ electrode, a dye layer, an electrolyte, a platinum layer, and glass were sequentially laminated. Was done. The structures of RE-1 and RE-2 in Table 1 used in place of the salt of the present invention, and I-
1 is shown.

[0153]

[Table 1]

[0154]

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2-4. Measurement of photoelectric conversion efficiency A 500 W xenon lamp (made by Ushio) was used for AM1.
5 Simulated sunlight containing no ultraviolet light was generated by passing through a filter (manufactured by Oriel) and a sharp cut filter (Kenko L-41), and the intensity of the light was adjusted to 80 mW / cm ² .

An alligator clip was connected to the conductive glass and the platinum-deposited glass of the photoelectrochemical cell, and
Simulated sunlight was irradiated at 5 ° C., and the generated electricity was measured by a current / voltage measuring device (Keithley SMU238 type). The open-circuit voltage (Voc), short-circuit current density (Jsc), and form factor (F
F) [= maximum output / (open circuit voltage × short circuit current)], conversion efficiency (η) and constant temperature and humidity (80 ° C., 70% RH)
Table 2 below shows the rate of decrease in short-circuit current density after 400 hours.

[0157]

[Table 2]

A photoelectrochemical cell (P-101) using a comparative electrolyte solution using a solvent has low initial performance and extremely poor durability because the solvent is volatilized. In addition, batteries (P-102, P-1) using molten salts RE-1 and RE-2 of comparative compounds.
03, P-104), the deterioration with time is small, but the photoelectric conversion performance is not sufficient. On the other hand, when the charged composition containing the salt represented by the general formula (1) is used, the initial performance such as the short-circuit current density and the conversion efficiency and the durability are excellent. Such an effect was observed when any of the dyes was used.

Example 3 Lithium secondary battery 3-1. Preparation of Positive Electrode Sheet As a positive electrode active material, 43 parts by mass of LiCoO ₂ , ₂ parts by mass of flake graphite, 2 parts by mass of acetylene black, and 3 parts by mass of polyacrylonitrile as a binder were added, and kneaded with 100 parts by mass of acrylonitrile as a medium. The obtained slurry was applied to an aluminum foil having a thickness of 20 μm using an extrusion coating machine, dried, compression-molded by a calender press, and an aluminum lead plate was welded to an end portion to form a thick plate. A positive electrode sheet having a thickness of 95 μm, a width of 54 mm and a length of 49 mm was prepared.

3-2. Preparation of Negative Electrode Sheet 43 parts by mass of a mesoface pitch-based carbon material (Petoka) as a negative electrode active material, 2 parts by mass of acetylene black and 2 parts by mass of graphite as a conductive agent were mixed, and polyacrylonitrile was further used as a binder. 3 parts by mass were added and kneaded with 100 parts by mass of N-methylpyrrolidone as a medium to obtain a negative electrode mixture slurry. The negative electrode mixture slurry was applied to a 10 μm-thick copper foil using an extrusion coating machine, dried, and compression-molded by a calender press to prepare a negative electrode sheet having a thickness of 46 μm, a width of 55 mm and a length of 50 mm. . After welding a lead plate made of nickel to the end of the negative electrode sheet, the lead plate was dried in a dry air having a dew point of −40 ° C. or less.
Heat treatment was performed at 0 ° C. for 1 hour. The heat treatment was performed using a far infrared heater.

3-3. Preparation of Sheet Battery The negative electrode sheet and the positive electrode sheet were each dehydrated and dried at 230 ° C. for 30 minutes in dry air having a dew point of −40 ° C. or less. In a dry atmosphere, a dehydrated and dried positive electrode sheet having a width of 54 mm × length of 49 mm, a separator (polyethylene porous film) cut into a width of 60 mm × length of 60 mm, and a nonwoven fabric were laminated, and the composition shown in Table 3 was placed on the nonwoven fabric. Electrolyte (E-2
02 to 211) in the same amount of acetonitrile was applied, and acetonitrile was distilled off at 50 ° C. under reduced pressure.
In addition, the electrolyte solution (E-201) using the solvent was directly permeated into the nonwoven fabric. As shown in Table 3, polymerization was performed by heating depending on the electrolyte used. 55m wide on it
mx 50 mm length of dehydrated and dried negative electrode sheet laminated,
A sheet type battery (B-101 to 111) was produced by using an exterior material made of a laminated film of polyethylene (50 μm) -polyethylene terephthalate (50 μm) and heat-sealing the four edges under vacuum to seal. FIG. 2 schematically shows the configuration of the sheet-type battery. The positive electrode sheet 31, the solid polymer electrolyte 32, the negative electrode sheet 33, the positive electrode terminal 34, and the negative electrode terminal 35 are configured as shown in FIG.
-101 to 111). The structure of RE-3 in Table 3 used for the batteries for Examples and Comparative Examples is shown below.

[0162]

[Table 3]

[0163]

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3-4. Evaluation of Battery Performance The sheet-type battery produced by the above method was repeatedly charged and discharged 10 times under the conditions of a current density of 2.3 mA / cm ² , a charge end voltage of 4.2 V, and a discharge end voltage of 2.6 V.
The discharge capacity at the 0th cycle was determined. This was examined for five batteries of the same prescription, and the average was taken as the capacity of the battery. In this way, the capacity of each battery is obtained, and S
The relative capacity to B-1 was determined. Further, the discharge capacity at the 200th cycle of each battery was determined, and the ratio to the discharge capacity at the 10th cycle was calculated and represented as the cycle capacity. Table 4 shows each value.

[0165]

[Table 4]

From the above results, it can be seen that the molten salt electrolyte containing the compound of the present invention has improved cycleability without a decrease in capacity.

[0167]

According to the present invention, it is possible to provide an electrolyte composition which does not substantially volatilize and is excellent in charge transport performance. By using this, it is possible to provide excellent durability with little deterioration in performance over time. Electrochemical cell, especially excellent in photoelectric conversion characteristics,
It is possible to provide a photoelectrochemical battery with less deterioration in characteristics over time and a non-aqueous secondary battery having excellent cycle characteristics without reducing the battery capacity.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing the structure of a preferred photoelectric conversion element of the present invention.

FIG. 2 is a diagram showing a configuration of a sheet battery manufactured in Example 3.

[Explanation of symbols]

 Reference Signs List 10 photoelectric conversion element 12 conductive layer 14 undercoat layer 16 photosensitive layer 18 charge transport layer 20 ····················································································································· -Negative electrode sheet 34-Positive electrode terminal 35-Negative electrode terminal s-Semiconductor fine particles d-Dye t-Charge transport material

Continued on the front page (72) Inventor Shoichi Sen 210 Nakanuma, Minamiashigara-shi, Kanagawa Prefecture Fuji Photo Film Co., Ltd. F-term (reference) 4J005 BD06 4J100 AB07P AL08P BA02P BA08P BA12P BA27P BA32P BA58P BB07P BC73P CA01 CA03 DA56 FA03 JA15 JA45 JA0 5H AJ03 AJ05 AK03 AL02 AL04 AL06 AL07 AL08 AM02 AM03 AM04 AM05 AM07 BJ04 DJ09 5H032 AA06 AS16 AS19 CC16 EE16

Claims (12)

[Claims] 1. An electrolyte composition comprising a salt represented by the following general formula (1). Embedded image (In the formula (1), R ₁ and R ₂ each represent a substituent, and Y represents an organic or inorganic cation.) 2. In the general formula (1), Y is the following general formula:
Table in any of (2-a), (2-b) and (2-c)
The electrolyte composition according to claim 1, which is an organic cation to be produced.
object. Embedded image(In the formula (2-a), Q_y1Is a 5- or 6-membered ring with a nitrogen atom
Represents an atomic group capable of forming an aromatic cation of_y1Is
Represents a substituted or unsubstituted alkyl or alkenyl group.
You. In the formula (2-b), A_y1Represents a nitrogen atom or a phosphorus atom
Then R_y1, R_y2, R _y3And R_y4Is replaced or omitted
Represents a substituted alkyl or alkenyl group. Also, R_y1,
R_y2, R_y3And R_y4Two or more of which combine with each other to form A
_y1May form a non-aromatic ring containing Equation (2-
c) where R_y1, R_y2, R_y3, R_y4, R_y5And R_y6Are each
Represents a substituted or unsubstituted alkyl or alkenyl group.
Then R_y3, R_y4, R_y5And R_y6Two or more of each other
They may combine to form a ring structure. Formula (2-a),
The compounds represented by the formulas (2-b) and (2-c)
Q _y1, R_y1, R_y2, R_y3, R_y4, R_y5Or R_y6Centered around
To form a multimer. ) 3. The electrolyte composition according to claim 1, wherein in the general formula (1), Y is a lithium cation. 4. The electrolyte composition according to claim 1, wherein in the general formula (1), at least one of R ₁ and R ₂ contains a substituted or unsubstituted ethyleneoxy group. 5. The method according to claim 1, wherein in the general formula (1), _one of R ₁ and R ₂ contains a fluorine-substituted alkyl group.
The electrolyte composition according to any one of the above. 6. The electrolyte composition according to claim ₁ , wherein in the general formula (1), at least one of R ₁ , R ₂ and Y contains a polymerizable group. 7. The electrolyte composition according to claim 1, wherein in the general formula (1), at least one of an anion and a cation is a polymer. 8. The electrolyte composition according to claim 1, comprising an iodine salt compound and iodine. 9. At least two kinds of salts represented by the above general formula (1), at least one kind of which is a salt of lithium cation, and the other Y is a salt of the above general formula (2-a), (2 −
The electrolyte composition according to any one of claims 3 to 8, which is a salt of a cation represented by any of b) and (2-c). 10. An electrochemical cell comprising the electrolyte composition according to claim 1. Description: 11. A photoelectrochemical cell having a charge transport layer containing the electrolyte composition, a photosensitive layer containing a dye-sensitized semiconductor, and a counter electrode. An electrochemical battery according to claim 1. 12. The electrochemical cell according to claim 10, wherein the electrochemical cell is a non-aqueous secondary battery.