JP2008034256A - Nonaqueous electrolyte battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte battery which is equipped with a negative electrode containing a carbonaceous material, and in which high rate discharge characteristics of the nonaqueous electrolyte battery using an ionic liquid having aliphatic quaternary ammonium cation can be enhanced, and put into practical use. <P>SOLUTION: A nonaqueous electrolyte containing an alicyclic quaternary ammonium cation having a five-membered ring and containing cyclic carbonate esters is used. As one of the cyclic carbonate esters, ethylene carbonate is preferable. That is, by adding the cyclic carbonate esters, the high rate discharge characteristics of the nonaqueous electrolyte battery equipped with the negative electrode containing the carbonaceous material and using the ionic liquid having the aliphatic quaternary ammonium cation can be improved. Especially, by selecting the alicyclic quaternary ammonium cation having the five-membered ring as the alicyclic quaternary ammonium cation, compared with the case of using the ionic liquid having the alicyclic quaternary ammonium cation having a six-membered ring, high rate discharge characteristics can be enhanced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nonaqueous electrolyte battery using a nonaqueous electrolyte containing an ionic liquid.

  In recent years, non-aqueous electrolyte batteries typified by lithium ion secondary batteries have attracted attention as power supplies for electronic equipment, power storage power supplies, electric vehicle power supplies, and the like that have been improved in performance and size.

  These non-aqueous electrolyte batteries generally use a non-aqueous electrolyte (non-aqueous electrolyte) that is liquid at room temperature. The non-aqueous electrolyte is generally obtained by dissolving a lithium salt that is solid at room temperature in an organic solvent that is liquid at room temperature. Examples of the organic solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl. Organic solvents such as carbonate, methyl ethyl carbonate, γ-butyrolactone and dimethoxyethane are used.

  On the other hand, it has been proposed to use an ionic liquid that is liquid at room temperature as a non-aqueous electrolyte for a non-aqueous electrolyte battery. The ionic liquid itself is liquid at room temperature but is substantially non-volatile and has high flame retardancy. Among non-aqueous electrolytes, the use of non-aqueous electrolytes that have characteristics such as no risk of ignition is desired, particularly for relatively large non-aqueous electrolyte applications such as power storage power sources and electric vehicle power sources. A technique using the ionic liquid as an electrolyte has attracted attention.

  Ionic liquids are also called room temperature molten salts, and those having a quaternary ammonium organic cation are known. Specifically, in Patent Document 2, “as the quaternary ammonium organic cation having a skeleton represented by (Chemical Formula 1), imidazolium ions such as dialkylimidazolium ions and trialkylimidazolium ions, tetraalkylammonium ions, pyridinium” Ion, pyrazolium ion, pyrrolium ion, pyrrolinium ion, pyrrolidinium ion, piperidinium ion, etc. In particular, an imidazolium cation having a skeleton represented by (Chemical Formula 2) or a skeleton represented by (Chemical Formula 3). Or any of the pyridinium cations having an aromatic quaternary ammonium cation (imidazolium ions such as dialkylimidazolium ions, trialkylimidazolium ions, tetra Such as those having an alkyl group such as ruyl ammonium ion, pyridinium ion, pyrazolium ion, and pyrrolium ion, and those having an aliphatic quaternary ammonium cation (such as pyrrolium ion, pyrrolidinium ion, and piperidinium ion). The ionic liquid having an aromatic quaternary ammonium cation has problems such as higher viscosity and higher melting point than the ionic liquid having an aromatic quaternary ammonium cation. The aliphatic quaternary ammonium cations include those having a five-membered ring (such as pyrrolinium ion and pyrrolidinium ion) and those having a six-membered ring (such as piperidinium ion).

  Furthermore, it is known that an ionic liquid having an aliphatic quaternary ammonium cation has a feature of high reduction resistance compared to an ionic liquid having an aromatic quaternary ammonium cation. Application to a non-aqueous electrolyte battery using a battery has been proposed. However, a non-aqueous electrolyte battery using an ionic liquid having an aliphatic quaternary ammonium cation for the non-aqueous electrolyte and a carbonaceous material for the negative electrode cannot be put into practical use because the charge / discharge efficiency of the negative electrode is too low. was there.

  On the other hand, in order to improve the characteristics of a battery using an ionic liquid as a non-aqueous electrolyte, a technique of adding a cyclic ester having a π bond such as vinylene carbonate is known (see Patent Document 1). However, since vinylene carbonate etc. are very expensive additives, the technique which can avoid use of vinylene carbonate etc. was calculated | required from the point of cost.

In addition, since the non-aqueous electrolyte using an ionic liquid has a higher viscosity than the general non-aqueous electrolyte described above, in order to improve the high rate discharge characteristics of a battery using the non-aqueous electrolyte, for example, In Patent Document 1, “The nonaqueous electrolyte of the battery of the present invention may be used by adding an organic solvent that is liquid at room temperature in addition to a lithium salt, a room temperature molten salt, and a cyclic ester having a π bond. Here, as the organic solvent, organic solvents generally used for electrolytes for non-aqueous electrolyte batteries can be used, for example, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, diphenyl carbonate, tetrahydrofuran, dimethoxyethane, diethoxyethane. , Methoxyethoxyethane, etc., but are not limited to these, although these organic solvents are described above. As it is flammable, the non-aqueous electrolyte may become flammable and there is a possibility that sufficient safety may not be obtained if the amount is too large. ”(Paragraph 0023) It has also been proposed to mix low-viscosity chain esters, etc., but the flame retardancy characteristics of ionic liquids are lost, so if these solvents are added, the addition amount should be as small as possible There was a need for technology that could
JP 2002-373704 A

  The present invention has been made in view of the above problems, includes a negative electrode containing a carbonaceous material, and enhances the high rate discharge characteristics of a non-aqueous electrolyte battery using an ionic liquid having an aliphatic quaternary ammonium cation, An object is to provide a nonaqueous electrolyte battery that can be put into practical use.

  The configuration of the present invention for solving the above-described problems is as follows. However, the action mechanism includes estimation, and the success or failure of the action mechanism does not limit the present invention.

(1) A positive electrode, a non-aqueous electrolyte, and a negative electrode containing a carbonaceous material are included, and the non-aqueous electrolyte contains an aliphatic cyclic quaternary ammonium cation having a five-membered ring and cyclic carbonates. A non-aqueous electrolyte battery characterized by comprising:
(2) The nonaqueous electrolyte battery according to (1), wherein the cyclic carbonate is ethylene carbonate.

  Examples of the aliphatic cyclic quaternary ammonium organic cation having a five-membered ring include a pyrrolinium cation and a pyrrolidinium cation.

  Examples of the pyrrolium cation include 1,2-dimethylpyrrolium ion, 1-ethyl-2-methylpyrrolium ion, 1-propyl-2-methylpyrrolium ion, 1-butyl-2-methylpyrrolium ion, and the like. Although it is mentioned, it is not limited to these.

  Examples of the pyrrolidinium cation include 1,1-dimethylpyrrolidinium ion, 1-ethyl-1-methylpyrrolidinium ion, 1-methyl-1-propylpyrrolidinium ion, 1-butyl-1-methylpyrrolidinium ion, and the like. However, it is not limited to these.

  In addition, the ionic liquid which has these aliphatic cyclic | annular quaternary ammonium organic substance cations may be used independently, and may be used in mixture of 2 or more types.

The non-aqueous electrolyte according to the present invention is used by mixing a lithium salt. The anion constituting the ionic liquid and the lithium salt is preferably a fluorine-containing anion. The fluorine-containing anion is not particularly limited, but BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , SO ₂ CF ₂ −, N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ^{_{2 F 5 SO 2) 2 -}} , N (CF 3 SO 2) (C 2 F 5 SO 2) -, N (CF 3 SO 2) (C 4 F 9 SO 2) -, C (CF 3 SO 2) ₃ ⁻ , C (C ₂ F ₅ SO ₂ ) ₃ ^{— and the} like. Among them, PF ₆ ⁻ , N (CF ₃ SO ₂ ) ₂ ⁻ , N (C ₂ F ₅ SO ₂ ) ₂ ⁻ , N ( CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) ⁻ , C (CF ₃ SO ₂ ) ₃ ⁻ , C (C ₂ F ₅ SO ₂ ) ₃ ⁻ It is preferable from the viewpoint of securing battery characteristics. ₆ ^- a to contain a concentration of more than 0.5 mol / l, from the viewpoint of the flame retardancy securing of the non-aqueous electrolyte. These anions may be used alone or in combination of two or more. When two or more kinds of anions are contained, an ionic liquid having two or more kinds of anions and a lithium salt comprising one kind of anions may be mixed, and two or more kinds of lithium salts having different anions may be mixed with one kind of anion. An ionic liquid may be mixed, and further, an ionic liquid having a different anion species and a lithium salt may be mixed. Among them, out of the anion constituting the anion and a lithium salt that constitutes the ionic liquid, one PF ₆ ^- is an inorganic anion such as, the other is ^{_{N (CF 3 SO 2) 2}} -, N (C 2 F 5 SO ^{_{2) 2 -, N (CF}} 3 sO 2) (C 4 F 9 sO 2) -, C (CF 3 sO 2) 3 -, C (C 2 F 5 sO 2) 3 - to be the organic anion such as It is preferable to combine them.

  Cyclic carbonates are not particularly limited and include ethylene carbonate, propylene carbonate, butylene carbonate, and the like. Of these, ethylene carbonate is particularly preferable.

  According to the present invention, the addition of cyclic carbonates improves the high rate discharge characteristics of a non-aqueous electrolyte battery using an ionic liquid having a negative electrode containing a carbonaceous material and having an aliphatic quaternary ammonium cation. it can. In particular, when an ionic liquid having an aliphatic cyclic quaternary ammonium cation having a six-membered ring is used by selecting an aliphatic cyclic quaternary ammonium cation having a five-membered ring as the aliphatic cyclic quaternary ammonium cation. In comparison, high rate discharge characteristics can be improved.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these descriptions.

  The nonaqueous electrolyte according to the battery of the present invention may be mixed with not only the ionic liquid and the cyclic carbonates but also other liquid compounds at room temperature. For example, an organic solvent generally used for an electrolyte for a lithium secondary battery can be used. Specifically, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, γ-butyrolactone, propiolactone, valerolactone, tetrahydrofuran , Dimethoxyethane, diethoxyethane, methoxyethoxyethane and the like, but are not particularly limited thereto.

  You may further contain cyclic carbonates which have (pi) bond. For example, cyclic carbonates having a π bond in the ring such as vinylene carbonate, catechol carbonate, 1-phenyl vinylene carbonate, 1,2-diphenyl vinylene carbonate, styrene carbonate, vinyl ethylene carbonate, 4-methyl-4-vinyl- Examples thereof include, but are not limited to, cyclic carbonates having a π bond only outside the ring, such as 1,3-dioxane-2-one.

  In addition to the above, phosphate ester, which is a flame retardant solvent that is generally added to an electrolyte for a lithium secondary battery, may be used. Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoroethyl) phosphate, and tri (pentafluoro) phosphate. Propyl), tri (heptafluorobutyl) phosphate, and the like, but are not limited thereto. These may be used alone or in combination of two or more.

  The lithium cation content in the non-aqueous electrolyte is preferably in the range of 0.1 to 3 mol / l. When the content of the lithium salt is less than 0.1 mol / l, the electrolyte resistance is too large, and the charge / discharge efficiency of the battery decreases. On the contrary, if the content of the lithium salt exceeds 3 mol / l, the melting point of the non-aqueous electrolyte rises and it becomes difficult to maintain a liquid state at room temperature. In view of the above, the content of the lithium salt in the nonaqueous electrolyte is in the range of 0.1 to 3 mol / l, more specifically in the range of 0.5 to 3 mol / l, in particular 0.5 to 2 mol. Desirably, the range is / l.

  In addition, the non-aqueous electrolyte in the present invention may be used by solidifying the non-aqueous electrolyte into a gel by combining a lithium salt and an organic compound that is liquid at room temperature, or a polymer. Here, examples of the polymer include, for example, polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, various acrylic monomers, methacrylic monomers, acrylamide monomers, allyl monomers, and styrene monomers. Examples include, but are not limited to, polymers. These may be used alone or in combination of two or more.

  Examples of the negative electrode active material that is a main component of the negative electrode of the nonaqueous electrolyte battery in the present invention include a carbonaceous material and a material that is modified by adding phosphorus or boron for the purpose of improving the negative electrode characteristics. . Among carbonaceous materials, graphite has a working potential very close to that of metallic lithium. Therefore, when lithium salt is used as an electrolyte salt, self-discharge can be reduced, and irreversible capacity in charge / discharge can be reduced, which is preferable as a negative electrode active material. . Graphite crystals include the well-known hexagonal system and others belonging to the rhombohedral system. In particular, rhombohedral graphite has a wide selectivity for a solvent in an electrolytic solution. For example, an organic compound that easily co-inserts with lithium ions or an organic compound that is easily reductively decomposed at a relatively noble potential can be obtained using a non-aqueous solution. Even when it is used as a constituent material of an electrolyte, it is desirable because delamination is suppressed and excellent charge / discharge efficiency is exhibited.

The analysis results by X-ray diffraction etc. of rhombohedral graphite that can be suitably used are shown below;
Lattice constant a0 = 0.3635 nm, α = 39.49 °

  Most natural graphite and artificial graphite are hexagonal, but it is known that rhombohedral structures exist in natural graphite and artificial graphite heat-treated at very high temperatures. It is also known that there is an increase from hexagonal to rhombohedral by grinding or grinding. In particular, graphite having a large amount of rhombohedral system on the surface of the graphite particle and a large amount of hexagonal system inside the particle is most desirable in terms of advantages such as high capacity, solvent resistance, and manufacturing process.

  Here, the calculation method of the rhombohedral system contained in the whole graphite crystal described in JP-A-2000-348727 is shown. The peak area of the (101) diffraction line attributed to the rhombohedral crystal measured by the X-ray wide angle diffraction method is represented by r (101), and the peak area of the (101) diffraction line attributed to the hexagonal crystal measured in the same manner. It is assumed that h (101) is used, and the ratio R% of the rhombohedral crystal in the entire graphite crystal is calculated by (Equation 1).

(Formula 1) R = {r (101) × 12/15} / {r (101) × 15/12 + h (101)} × 100
Since rhombohedral graphite is desirably contained in an amount of 5% or more of the negative electrode carbonaceous material because of the effect of greatly reducing the irreversible capacity in the initial charge / discharge, 15% is required to obtain a more remarkable effect. It is desirable to include the above.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these descriptions.

(Invention electrolyte 1)
Liquid at room temperature with 0.5 liter of 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide (MPPr-TFSI) as an ionic liquid and 0.15 liter of ethylene carbonate (EC) as a cyclic carbonate A nonaqueous electrolyte was obtained by mixing 0.35 liter of diethyl carbonate (DEC), which is a compound of the above, and further mixing 1 mol of LiPF ₆ as a lithium salt.

(Invention electrolyte 2)
MPPr-TFSI 0.5 liter, EC 0.25 liter, and DEC 0.25 liter were mixed, and 1 mol of LiPF ₆ was further mixed to obtain a nonaqueous electrolyte.

(Invention electrolyte 3)
A nonaqueous electrolyte was obtained by mixing 0.5 liters of MPPr-TFSI, 0.25 liters of EC and 0.25 liters of propylene carbonate (PC) which is a cyclic carbonate, and further mixing 1 mol of LiPF ₆ .

(Invention electrolyte 4)
Mixed MPPr-TFSI0.5 liter and EC0.5 liter, by further mixing 1 mol of LiPF _6, to obtain a non-aqueous electrolyte.

(Invention electrolyte 5)
By mixing 0.5 liters of MPPr-TFSI, 0.1 liters of EC, 0.35 liters of DEC and 0.05 liters of vinylene carbonate (VC) which is a cyclic carbonate, and further mixing 1 mol of LiPF ₆ , non-water An electrolyte was obtained.

(Invention electrolyte 6)
Mixed MPPr-TFSI0.5 liter and EC0.1 liters and DEC0.4 liter, by further mixing 1 mol of LiPF _6, to give a non-aqueous electrolyte.

(Invention electrolyte 7)
Mixed MPPr-TFSI0.5 liter and PC0.15 liters and DEC0.35 liter, by further mixing 1 mol of LiPF _6, to obtain a non-aqueous electrolyte.

(Invention electrolyte 8)
MPPr-TFSI 0.25 liter, EC 0.375 liter, and DEC 0.375 liter were mixed, and 1 mol of LiPF ₆ was further mixed to obtain a nonaqueous electrolyte.

(Invention electrolyte 9)
MPPr-TFSI 0.3 liter, EC 0.35 liter and DEC 0.35 liter were mixed, and further 1 mol of LiPF ₆ was mixed to obtain a non-aqueous electrolyte.

(Invention electrolyte 10)
Mixed MPPr-TFSI0.75 liter and EC0.125 liters and DEC0.125 liter, by further mixing 1 mol of LiPF _6, to obtain a non-aqueous electrolyte.

(Invention electrolyte 11)
Mixed MPPr-TFSI0.8 liter and EC0.1 liters and DEC0.1 liter, by further mixing 1 mol of LiPF _6, to obtain a non-aqueous electrolyte.

(Invention electrolyte 12)
The ionic liquid 1-methyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide (MBPr-TFSI) 0.5 liter, EC0.25 liter and DEC 0.25 liter are mixed, and 1 mol of LiPF ₆ is mixed. Was mixed to obtain a non-aqueous electrolyte.

(Comparative electrolyte 1)
Mixed MPPr-TFSI0.5 liter and DEC0.5 liter, by further mixing 1 mol of LiPF _6, to obtain a non-aqueous electrolyte.

(Comparative electrolyte 2)
Mix 0.5 liter of 1-methyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide (MPPp-TFSI) which is an ionic liquid, 0.25 liter of EC and 0.25 liter of DEC, and further mix 1 mol of LiPF ₆ As a result, a non-aqueous electrolyte was obtained.

(Comparative electrolyte 3)
By mixing 1 mol of LiPF ₆ with 1 liter of MPPr-TFSI, a non-aqueous electrolyte was obtained.

(Comparative electrolyte 4)
By mixing 1 mol of LiPF ₆ with 1 liter of MPPp-TFSI, a non-aqueous electrolyte was obtained.

(Electrolyte flammability test)
An electrolyte flammability test was performed on the above-described electrolytes 1 to 12 and comparative electrolytes 1 to 3 described above. A glass filter was impregnated with each electrolyte, and the presence of ignition / combustion was confirmed by bringing the fire of an alcohol lamp closer to 10 seconds.

(Preparation of non-aqueous electrolyte battery)
A non-aqueous electrolyte battery was produced using the present electrolytes 1 to 12 and comparative electrolytes 1 and 2. Let this be the present invention batteries 1 to 12 and comparative batteries 1 and 2. A cross-sectional view of the nonaqueous electrolyte battery according to the example is shown in FIG. The non-aqueous electrolyte battery according to the example is composed of a pole group 4 including a positive electrode 1, a negative electrode 2, and a separator 3, a non-aqueous electrolyte, and a metal resin composite film 5 as an exterior material. The positive electrode 1 is formed by applying a positive electrode mixture 11 on a positive electrode current collector 12. The negative electrode 2 is formed by applying a negative electrode mixture 21 on a negative electrode current collector 22. The nonaqueous electrolyte is impregnated in the pole group 4. The metal resin composite film 5 covers the pole group 4 and is sealed on all four sides by heat welding.

Next, a method for manufacturing the nonaqueous electrolyte battery having the above configuration will be described. The positive electrode 1 was obtained as follows. First, LiCoO ₂ and acetylene black as a conductive agent are mixed, and further, an N-methyl-2-pyrrolidone solution of polyvinylidene fluoride is mixed as a binder, and this mixture is used as a positive electrode current collector 12 made of aluminum foil. After coating on one side, it was dried and pressed so that the positive electrode mixture 11 had a predetermined thickness. The positive electrode 1 was obtained by the above process. The negative electrode 2 was obtained as follows. First, graphite as a negative electrode active material and an N-methyl-2-pyrrolidone solution of polyvinylidene fluoride as a binder were mixed, and this mixture was applied to one side of a negative electrode current collector 22 made of copper foil. It dried and it pressed so that the negative mix 21 might become predetermined thickness. The negative electrode 2 was obtained by the above process. As the separator 3, a polyethylene microporous membrane was used. The pole group 4 was configured by facing the positive electrode mixture 11 and the negative electrode mixture 21, placing the separator 3 therebetween, and laminating the positive electrode 1, the separator 3, and the negative electrode 2 in this order. Next, the electrode group 4 was impregnated with the non-aqueous electrolyte by immersing the electrode group 4 in the non-aqueous electrolyte. Furthermore, the pole group 4 was covered with the metal resin composite film 5, and the four sides were sealed by heat welding.

(Initial discharge capacity test)
An initial discharge capacity test was performed on the battery of the present invention and the comparative battery. The test temperature was 20 ° C. The charging was constant current charging with a current of 1 mA and a final voltage of 4.2 V, the discharging was constant current discharging with a current of 1 mA and a final voltage of 3.0 V, and the obtained discharge capacity was defined as the initial discharge capacity. The design capacities of the battery of the present invention and the comparative battery are all 10 mAh.

(High rate discharge test)
A high rate discharge test was performed on the battery of the present invention and the comparative battery. The test temperature was 20 ° C. A battery whose initial capacity was confirmed under the same conditions as in the initial discharge capacity test was charged under the same conditions, and then a constant current discharge with a current of 5 mA and a final voltage of 3.0 V was performed. The obtained discharge capacity was defined as a high rate discharge capacity.

  The above results are shown in Tables 1 to 4. In addition, in the result of the electrolyte flammability test of the nonaqueous electrolyte used for each battery, the combustion continued for 10 seconds while the fire of the alcohol lamp was approaching, but it showed self-extinguishing properties when the alcohol lamp was moved away. Is marked with a triangle at the right end of each table, and also marked with a circle for those that ignited once within 10 seconds but immediately extinguished. All unmarked items indicate no ignition for 10 seconds.

  From Table 1, the high rate discharge capacity of the comparative batteries 4 and 3 using a non-aqueous electrolyte consisting only of an ionic liquid having a lithium salt and an aliphatic cyclic quaternary ammonium cation is less than 1 mAh, while other than the ionic liquid The high rate discharge capacity of the comparative battery 1 to which DEC, which is a chain ester, is added as a liquid organic compound at room temperature is improved to some extent. This is presumably because the migration of lithium ions was facilitated because the viscosity of the nonaqueous electrolyte was reduced by the addition of DEC, which is a chain ester. However, a non-aqueous electrolyte having a configuration in which a part of DEC, which is a chain ester, is replaced with EC, which is a cyclic ester, as an organic compound that is liquid at room temperature other than the ionic liquid with respect to the non-aqueous electrolyte used in the comparative battery 3. In comparative battery 2 using the present invention and battery 2 of the present invention, despite the fact that the EC viscosity is higher than that of DEC, the high-rate discharge capacity is greatly improved. In particular, when the other conditions are the same, a fatty acid having a five-membered ring as compared with the comparative battery 2 using a nonaqueous electrolyte containing MPPp, which is an aliphatic cyclic quaternary ammonium cation having a six-membered ring, is obtained. The battery 2 of the present invention in which the nonaqueous electrolyte containing MPPr, which is a group quaternary ammonium cation, is selected is remarkably excellent in high rate discharge characteristics.

  From Table 2, it can be seen that the cyclic carbonates are preferably ethylene carbonate.

  From Table 3, the cyclic carbonates are contained in a range satisfying the condition of 30% by volume or more of the organic compound that is liquid at room temperature other than the ionic liquid from the viewpoint of high rate discharge characteristics, and further non-aqueous. It turns out that it is preferable also from the point of the flame retardance of electrolyte.

  From the viewpoint of the flame retardancy of the non-aqueous electrolyte, from Table 4, the content of the ionic liquid in the non-aqueous electrolyte is preferably 30 volume percent or more, and from the viewpoint of combining good battery performance, It can be seen that the content of the ionic liquid in the water electrolyte is preferably less than 75 volume percent.

  As described above, the case where MPPr is used as the aliphatic cyclic quaternary ammonium cation having a five-membered ring has been shown. However, even when MBPr is used as the aliphatic cyclic quaternary ammonium cation having a five-membered ring, Similar effects were confirmed as shown by the data with Invention Battery 12.

  As can be seen from Table 6, the nonaqueous electrolyte may contain a cyclic carbonate having a π bond, and the nonaqueous electrolyte battery having both the flame retardancy of the electrolyte and good battery performance can be more easily obtained. Obtainable.

  As is apparent from the above results, according to the present invention, a battery having high energy density, high energy density, high rate discharge characteristics, etc., obtained by using an ionic liquid as a nonaqueous electrolyte A nonaqueous electrolyte battery excellent in performance can be provided.

It is sectional drawing of the nonaqueous electrolyte battery which concerns on an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode 11 Positive electrode mixture 12 Positive electrode collector 2 Negative electrode 21 Negative electrode mixture 22 Negative electrode collector 3 Separator 4 Electrode group 5 Metal resin composite film

Claims (2)

A positive electrode, a nonaqueous electrolyte, and a negative electrode containing a carbonaceous material, wherein the nonaqueous electrolyte contains an aliphatic cyclic quaternary ammonium cation having a five-membered ring and cyclic carbonates. Non-aqueous electrolyte battery characterized. The non-aqueous electrolyte battery according to claim 1, wherein the cyclic carbonate is ethylene carbonate.

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