TW201817076A - Additive for nonaqueous electrolyte solutions, nonaqueous electrolyte solution and electricity storage device - Google Patents

Abstract

Disclosed is an additive for nonaqueous electrolyte solutions, which contains a compound represented by formula (1). In formula (1), each of R1 and R2 independently represents an alkyl group having 1-8 carbon atoms, which may be substituted by a halogen atom, or the like; and A represents a hydrogen atom or a halogen atom.

Description

Additive for non-aqueous electrolyte, non-aqueous electrolyte, and power storage device

The present invention relates to an additive for a non-aqueous electrolyte. The present invention also relates to a non-aqueous electrolytic solution using the additive for a non-aqueous electrolytic solution and a power storage device using the non-aqueous electrolytic solution.

In recent years, with the increasing attention to the solution of environmental problems and the realization of a sustainable recycling society, non-aqueous electrolyte secondary batteries typified by lithium-ion batteries, and power storage devices such as electric double-layer capacitors are being widely carried out. Research. Among them, lithium-ion batteries are used as power sources for notebook personal computers and mobile phones due to their high operating voltage and energy density. Compared with lead batteries and nickel-cadmium batteries, lithium-ion batteries are expected to be new power sources due to their higher energy density and higher capacity. However, the lithium ion battery has a problem that the capacity of the battery decreases with the process of the charge and discharge cycle.

As a method of suppressing a decrease in the capacity of a battery accompanying a charge-discharge cycle, a method of adding various additives to an electrolytic solution is being studied. The additive decomposes during the initial charge and discharge, and forms a coating called Solid Electrolyte Interphase (SEI) on the electrode surface. Since the SEI is formed in the first cycle of the charge and discharge cycle, the decomposition of the solvent and the like in the electrolyte does not consume power, and lithium ions can travel back and forth between the electrodes through the SEI. That is, the formation of SEI helps prevent deterioration of power storage devices such as non-aqueous electrolyte secondary batteries during repeated charge and discharge cycles, and improves battery characteristics, storage characteristics, and load characteristics.

As a SEI-forming compound, for example, Patent Document 1 discloses charging and discharging of a lithium ion secondary battery by adding 1,3-propanesultone (PS) as an additive to an electrolytic solution. Improved cycle characteristics. In addition, Patent Document 2 discloses that 1,3,2-dioxaphospholane-2-dioxide (1,3,2-dioxaphospholane-2-dioxide) derivative is added to the electrolytic solution. Or PS as an additive reduces the self-discharge rate of the non-aqueous electrolyte secondary battery. Patent Document 3 discloses that a discharge characteristic of a lithium ion secondary battery is improved by adding a derivative of vinylene carbonate (VC) as an additive. [Prior Art Literature] [Patent Literature]

[Patent Literature 1] Japanese Patent Laid-Open No. 63-102173 [Patent Literature 2] Japanese Patent Laid-Open No. 10-050342 [Patent Literature 3] Japanese Patent Laid-Open No. 05-074486

[Problems to be Solved by the Invention] However, even if these additives are used, sufficient performance cannot be obtained, and it is desired to develop novel additives that further improve the battery characteristics of power storage devices.

An object of the present invention is to provide an additive for a non-aqueous electrolyte, which improves battery characteristics in terms of long-term cycle characteristics and resistance characteristics, and initial resistance characteristics when used in a power storage device such as a non-aqueous electrolyte secondary battery. Another object of the present invention is to provide a non-aqueous electrolytic solution using the additive for a non-aqueous electrolytic solution and a power storage device using the non-aqueous electrolytic solution. [Means for solving problems]

That is, this invention is an additive for nonaqueous electrolyte solutions containing the compound represented by following formula (1). The present invention also relates to the use or application of the compound for producing an additive for a non-aqueous electrolyte.

[Chemical 1]

In formula (1), R ¹ and R ² each independently represent a fluorine atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, and Halogen atom-substituted alkynyl groups having 2 to 6 carbon atoms, aryl groups which may be substituted by halogen atoms, alkoxy groups which may be substituted by halogen atoms, alkoxy groups having 1 to 8 carbon atoms, and Alkenyloxy, alkynyloxy having 2 to 6 carbon atoms which may be substituted with a halogen atom, or aryloxy group which may be substituted with a halogen atom. A represents a hydrogen atom or a halogen atom. [Effect of the invention]

According to the present invention, it is possible to provide an additive for a non-aqueous electrolyte solution that improves battery characteristics in terms of long-term cycle characteristics and resistance characteristics, and initial resistance characteristics when used in a power storage device such as a non-aqueous electrolyte secondary battery. In addition, the present invention can provide a non-aqueous electrolytic solution using the additive for a non-aqueous electrolytic solution and a power storage device using the non-aqueous electrolytic solution.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

The additive for a non-aqueous electrolyte according to one embodiment includes a compound represented by the following formula (1).

[Chemical 2]

In the formula (1), R ¹ and R ² each independently or individually represent a fluorine atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, and an olefin having 2 to 6 carbon atoms which may be substituted with a halogen atom. Group, alkynyl group having 2 to 6 carbon atoms which can be substituted with halogen atom, aryl group which can be substituted with halogen atom, alkoxy group having 1 to 8 carbon atoms which can be substituted with halogen atom, carbon number which can be substituted with halogen atom An alkenyloxy group of 2 to 6, an alkynyloxy group of 2 to 6 carbon atoms which may be substituted by a halogen atom, or an aryloxy group which may be substituted by a halogen atom. A represents a hydrogen atom or a halogen atom. In the present specification, the "substitutable with a halogen atom" means that at least one of hydrogen atoms included in an alkyl group such as R ¹ or R ² may be substituted with a halogen atom.

Examples of the alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, third butyl, and tris. Fluoroethyl. Wherein, the alkyl group may be a methyl group.

Examples of the alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom include vinyl, allyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, Isobutenyl, and 1,1-difluoro-1-propenyl. The alkenyl group may be an allyl group which may be substituted with a halogen atom.

Examples of the alkynyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom include 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, and 3-butynyl base. The alkynyl group may be a 2-propynyl group which may be substituted by a halogen atom.

Examples of the aryl group which may be substituted with a halogen atom include a phenyl group, a tolyl group, a xylyl group, a naphthyl group, and a pentafluorophenyl group.

Examples of the alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom include a methoxy group, an ethoxy group, an n-propoxy group, an n-butoxy group, and a trifluoromethoxy group. The alkoxy group may be an alkoxy group having 1 to 3 carbon atoms, or a methoxy group.

Examples of the alkenyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom include an allyloxy group, a 1-methyl-2-propenyloxy group, and a 2-methyl-2-propenyloxy group. , 2-butenyloxy, 3-butenyloxy, and propenyloxy. The alkenyloxy group may be an alkenyloxy group having 2 to 4 carbon atoms, or an allyloxy group.

Examples of the alkynyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom include 2-propynyloxy, 1-methyl-2-propynyloxy, and 2-methyl-2-propane Alkynyloxy, 2-butynyloxy, and 3-butynyloxy. The alkynyloxy group may be an alkynyloxy group having 2 to 4 carbon atoms, or a 2-propynyloxy group.

Examples of the aryloxy group which may be substituted with a halogen atom include a phenoxy group, a 2-methylphenoxy group, a 3-methylphenoxy group, a 4-methylphenoxy group, and a 2-ethylphenoxy group. , 3-ethylphenoxy, 4-ethylphenoxy, 2-methoxyphenoxy, 3-methoxyphenoxy, and 4-methoxyphenoxy. Wherein, the aryloxy group may be a phenoxy group which may be substituted with a halogen atom.

Examples of the halogen atom represented by A in the formula (1) include an iodine atom, a bromine atom, and a fluorine atom. Among these, A may be a fluorine atom from the viewpoint that the battery resistance is further lowered.

The compound represented by the formula (1) can be produced by using an available raw material in combination with an ordinary reaction. For example, in the compound represented by formula (1), a compound in which R ¹ and R ² are both methyl groups and A is a hydrogen atom can be obtained by a method of reacting dimethylphosphine chloride with 3-hydroxycyclobutane Manufacturing.

Examples of the compound represented by the formula (1) include 3- (difluorophosphinoyloxy) tetrahydrothiophene-1,1-dioxide, and 3-dimethyloxyphosphinooxytetrayl Hydrothiophene-1,1-dioxide, 3-diethylphosphinoyloxytetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethylphosphinoyloxytetrahydrothiophene- 1,1-dioxide, 3-diphenylphosphinooxytetrahydrothiophene-1,1-dioxide, 3-bis-allylphosphinooxytetrahydrothiophene-1,1- Dioxide, 3-divinyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-dipropargyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3 -Dimethoxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-diethoxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-diphenoxy Phenylphosphinooxytetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethoxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-bis-allyl Phenyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-bis-cyclohexyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-dimethyl Phosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide Ethylphosphinooxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethylphosphinooxy-4-fluorotetrahydrothiophene-1,1-dioxide Compound, 3-diphenylphosphinoyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-diallylphosphinoyloxy-4-fluorotetrahydrothiophene-1,1 -Dioxide, 3-divinyloxyphosphinooxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-dipropargyloxyphosphinooxy-4-fluorotetrahydrothiophene- 1,1-dioxide, 3-dimethoxyphosphinoyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-diethoxyphosphinoyloxy-4-fluoro Tetrahydrothiophene-1,1-dioxide, 3-diphenoxyphosphinoyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3-bis-trifluoromethoxy-4 -Fluorophosphinoyloxytetrahydrothiophene-1,1-dioxide, 3-bis-allyloxy-4-fluorooxophosphinooxytetrahydrothiophene-1,1-dioxide, and 3-Bis-cyclohexyloxyphosphinooxy-4-fluorotetrahydrothiophene-1,1-dioxide.

Among them, from the viewpoint of further suppressing the initial resistance, the additive for a non-aqueous electrolyte may include at least one compound selected from the group consisting of 3- (difluorophosphinooxy) tetrahydrothiophene-1, 1-dioxide, 3-dimethyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-diphenyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-bis-allyloxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3 -Diphenoxyphosphinooxytetrahydrothiophene-1,1-dioxide, 3-dimethoxyphosphinyloxy-4-fluorotetrahydrothiophene-1,1-dioxide, 3 -Bis-allyloxy-4-fluorotetrahydrothiophene-1,1-dioxide and 3-bis-2-propenyloxytetrahydrothiophene-1,1-dioxide.

The additive for a non-aqueous electrolytic solution according to the present embodiment may contain one kind or two or more kinds of compounds represented by the formula (1). If necessary, the additives for non-aqueous electrolytes may further include ordinary additives such as VC, Fluoroethylene carbonate (FEC), PS, etc., or negative electrode protecting groups, positive electrode protecting agents, flame retardants, and charging prevention Agent.

The non-aqueous electrolytic solution of one embodiment can be prepared, for example, by adding an additive for a non-aqueous electrolytic solution containing the compound represented by the formula (1) to a non-aqueous solvent in which an electrolyte is dissolved.

The content of the non-aqueous electrolyte additive (or the compound represented by the formula (1)) in the non-aqueous electrolyte based on the total mass of the non-aqueous electrolyte is preferably 0.005% to 10% by mass. % Range. When the content of the non-aqueous electrolyte additive (or the compound represented by the formula (1)) is 0.005% by mass or more, more excellent battery characteristics can be obtained. When the content of the non-aqueous electrolytic solution additive (or the compound represented by the formula (1)) is 10% by mass or less, the viscosity of the non-aqueous electrolytic solution is unlikely to increase, and thus the ion mobility can be sufficiently secured. From the same viewpoint, the content of the additive for the non-aqueous electrolytic solution (or the compound represented by the formula (1)) may be in a range of 0.05% by mass to 10% by mass.

The non-aqueous solvent is preferably an aprotic solvent from the viewpoint of suppressing the viscosity of the non-aqueous electrolytic solution to be low. The non-aqueous solvent may be at least one selected from the group consisting of a cyclic carbonate, a chain carbonate, an aliphatic carboxylic acid ester, a lactone, a lactam, a cyclic ether, and a chain. Ethers, fluorenes, nitriles, and these halogen derivatives. Among them, a cyclic carbonate, a chain carbonate, or a combination of these may be used as the non-aqueous solvent.

Examples of the cyclic carbonate include ethyl carbonate, propylene carbonate, and butyl carbonate.

Examples of the chain carbonate include dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Examples of the aliphatic carboxylic acid ester include methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, and methyl trimethyl acetate.

Examples of the lactone include γ-butyrolactone.

Examples of the lactamamine include ε-caprolactam and N-methylpyrrolidone.

Examples of the cyclic ether include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, and 1,3-dioxolane.

Examples of the chain ether include 1,2-diethoxyethane and ethoxymethoxyethane.

Examples of the hydrazone include cyclamidine.

Examples of the nitrile include acetonitrile.

Examples of the halogen derivative include 4-fluoro-1,3-dioxolane-2-one, 4-chloro-1,3-dioxolane-2-one, and 4 , 5-difluoro-1,3-dioxolane-2-one.

These non-aqueous solvents can be used alone or in combination.

The electrolyte may be a lithium salt as an ion source of lithium ions. The electrolyte may be at least one lithium salt selected from the group consisting of LiAlCl ₄ , LiBF ₄ , LiPF ₆ , LiClO ₄ , LiAsF ₆ and LiSbF ₆ . The electrolyte may be LiBF _{4 from the} viewpoints that the degree of dissociation can increase the ion conductivity of the electrolytic solution, and further has the effect of suppressing the performance degradation of the power storage device due to long-term use by using redox resistance. LiPF ₆ or a combination of these. These electrolytes may be used alone or in combination of two or more.

When the electrolyte is LiBF ₄ , LiPF _6, or a combination thereof, the electrolyte may be combined with a non-aqueous solvent containing one or more cyclic carbonates and chain carbonates. In particular, LiBF ₄ , LiPF ₆ or a combination of these can be combined with ethylene carbonate and diethyl carbonate.

The concentration of the electrolyte in the non-aqueous electrolytic solution of this embodiment may be in a range of 0.1 mol / L to 2.0 mol / L. When the concentration of the electrolyte is 0.1 mol / L or more, more excellent discharge characteristics, charging characteristics, and the like can be obtained. When the concentration of the electrolyte is 2.0 mol / L or less, the viscosity of the non-aqueous electrolytic solution is difficult to increase, and thus the ion mobility can be sufficiently secured. From the same viewpoint, the concentration of the electrolyte may be in a range of 0.5 mol / L to 1.5 mol / L.

The non-aqueous electrolytic solution of this embodiment prepared as described above can be used as an electrolytic solution for a power storage device including a positive electrode and a negative electrode. More specifically, the non-aqueous electrolyte prepared by using the non-aqueous electrolyte additive according to this embodiment is used for a non-aqueous electrolyte secondary battery such as a lithium ion battery, or an electric storage device such as an electric double-layer capacitor such as a lithium ion capacitor. In the case of the battery, the long-term cycle characteristics can be improved, the long-term resistance increase can be suppressed, and the initial resistance can be suppressed to improve battery characteristics. Furthermore, since the additive for a non-aqueous electrolytic solution of this embodiment is stable in a non-aqueous electrolytic solution, it is also possible to suppress generation of gas such as carbon dioxide caused by decomposition on the positive electrode during charging, thereby improving battery performance and safety.

FIG. 1 is a cross-sectional view schematically showing an embodiment of a non-aqueous electrolyte secondary battery as an example of a power storage device. In FIG. 1, the non-aqueous electrolyte secondary battery 1 includes a positive electrode plate 4 as a positive electrode and a negative electrode plate 7 as a negative electrode. The positive electrode plate 4 includes a positive electrode current collector 2 and a positive electrode active material layer 3 provided on the inner surface side of the positive electrode current collector 2. The negative electrode plate 7 includes a negative electrode current collector 5 and a negative electrode active material layer 6 provided on the inner surface side of the negative electrode current collector 5. The positive electrode plate 4 and the negative electrode plate 7 are arranged to face each other with a non-aqueous electrolyte solution 8 interposed therebetween. The non-aqueous electrolyte solution 8 is provided with a spacer 9.

As the positive electrode current collector 2 and the negative electrode current collector 5, for example, a metal foil containing a metal such as aluminum, copper, nickel, or stainless steel can be used.

The positive electrode active material used in the positive electrode active material layer 3 may be a lithium-containing composite oxide. Examples thereof include LiMnO ₂ , LiFeO ₂ , LiCoO ₂ , LiMn ₂ O ₄ , Li ₂ FeSiO ₄ , and LiNi _1/3 Co. _1/3 Mn _1/3 O ₂ and LiFePO ₄ .

Examples of the negative electrode active material used in the negative electrode active material layer 6 include materials capable of occluding and releasing lithium. Examples of such materials include carbon materials such as graphite and amorphous carbon, and oxide materials such as indium oxide, silicon oxide, tin oxide, zinc oxide, and lithium oxide. As the negative electrode active material, lithium metal or a metal material capable of forming an alloy with lithium can also be used. Examples of the metal capable of forming an alloy with lithium include Cu, Sn, Si, Co, Mn, Fe, Sb, and Ag. Binary or ternary alloys containing these metals and lithium can also be used. These negative electrode active materials may be used alone or in combination of two or more.

As the spacer 9, for example, a porous film made of polyethylene, polypropylene, fluororesin, or the like can be used. [Example]

Hereinafter, the present invention will be described in more detail with examples.

Example 1 1. Synthesis of 3-dimethyloxyphosphinooxytetrahydrothiophene-1,1-dioxide (compound 1) in a 100 mL volume equipped with a stirrer, cooling tube, thermometer and dropping funnel In a four-necked flask, 50 mL of pyridine was charged to the four-necked flask, and 3-hydroxycyclobutane (6.8 g, 50 mmol) was added under an ice bath. Then, dimethylphosphine oxyphosphine (5.6 g, 50 mmol) was added dropwise under an ice bath, and after raising the temperature to 60 ° C, the reaction solution was stirred for 12 hours while maintaining the temperature. Then, after adding water and filtering a precipitate, it wash | cleaned by the pulp washing | cleaning using Methyl Tert-butyl Ether (MTBE). By drying the obtained crystal, 6.9 g of 3-dimethylphosphine oxide tetrahydrothiophene-1,1-dioxide (Compound 1) was obtained. The yield of Compound 1 was 65% relative to 3-hydroxycyclobutane. The obtained compound 1 was confirmed to have a molecular weight of 212 by liquid chromatography / mass spectrometry (Liquid Chromatography / Mass Spectrometry, LC / MS) spectrum.

2. Preparation of non-aqueous electrolyte solution Ethyl carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume composition ratio of EC: DEC = 30: 70 to obtain a mixed non-aqueous solvent. LiPF ₆ as an electrolyte was dissolved in the obtained mixed non-aqueous solvent so as to have a concentration of 1.0 mol / L. A non-aqueous electrolyte solution was prepared by adding Compound 1 as an additive for a non-aqueous electrolyte solution to the solution so that the content ratio to the total weight of the solution became 1.0% by mass.

(Example 2) 1. Synthesis of 3-diphenylphosphinooxytetrahydrothiophene-1,1-dioxide (Compound 2) In addition to dimethylphosphonium oxychloride (5.6 g, 50 mmol) was changed to diphenylphosphine chloride (11.8 g, 50 mmol), and the reaction was performed in the same manner to obtain 11.8 g of 3-diphenyloxyphosphinooxytetrahydrothiophene-1 , 1-dioxide (compound 2). The yield of Compound 2 was 70% relative to 3-hydroxycyclobutane. The obtained compound 2 was confirmed to have a molecular weight of 336 by LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 2 was used instead of Compound 1, a non-aqueous electrolyte was prepared in the same manner.

(Example 3) 1. Synthesis of 3-dimethoxyphosphinooxytetrahydrothiophene-1,1-dioxide (compound 3) 5.6 g, 50 mmol) was changed to dimethoxyphosphine chloride (7.2 g, 50 mmol), and the reaction was performed in the same manner to obtain 11.8 g of 3-dimethoxyphosphinooxytetrahydrogen Thiophene-1,1-dioxide (Compound 3). The yield of compound 3 was 63% relative to 3-hydroxycyclobutane. The obtained compound 3 was confirmed to have a molecular weight of 244 by LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 3 was used instead of Compound 1, a non-aqueous electrolyte was prepared in the same manner.

(Example 4) 1. Synthesis of 3-diallyloxyphosphinooxytetrahydrothiophene-1,1-dioxide (Compound 4) In addition to the dimethyloxychloride in Example 1, Phosphorus (5.6 g, 50 mmol) was changed to diallyloxy phosphorus oxychloride (7.2 g, 50 mmol), and the reaction was performed in the same manner to obtain 7.3 g of 3-diallyloxyoxy Phosphonyloxytetrahydrothiophene-1,1-dioxide (Compound 4). The yield of compound 4 was 49% relative to 3-hydroxycyclobutane. The obtained compound 4 was confirmed to have a molecular weight of 296 by LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 4 was used instead of Compound 1, a non-aqueous electrolyte was prepared in the same manner.

(Example 5) 1. Synthesis of 3-dimethoxyphosphinoyloxy-4-fluorotetrahydrothiophene-1,1-dioxide (compound 5) except for the 3-hydroxy ring in Example 3 The reaction was performed in the same manner except that butylamidine (6.8 g, 50 mmol) was changed to 4-fluoro-3-hydroxycyclobutylammonium (7.7 g, 50 mmol) to obtain 7.2 g of 3-dimethoxyphosphine oxide. An alkoxy-4-fluorotetrahydrothiophene-1,1-dioxide (compound 5). The yield of compound 5 was 55% relative to 4-fluoro-3-hydroxycyclobutane. The obtained compound 5 was confirmed to have a molecular weight of 262 by LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 5 was used instead of Compound 1, a non-aqueous electrolyte was prepared in the same manner.

(Example 6) 1. Synthesis of 3-diallyloxy-4-fluorotetrahydrothiophene-1,1-dioxide (compound 6) 6.8 g, 50 mmol) was changed to 4-fluoro-3-hydroxycyclobutane (7.7 g, 50 mmol), and the reaction was performed in the same manner to obtain 7.4 g of 3-diallyloxy-4- Fluorotetrahydrothiophene-1,1-dioxide (Compound 6). The yield of compound 6 was 47% relative to 4-fluoro-3-hydroxycyclobutane. The obtained compound 6 was confirmed to have a molecular weight of 314 by an LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 6 was used instead of Compound 1, a non-aqueous electrolyte was prepared in the same manner.

(Example 7) 1. Synthesis of 3- (difluorophosphinoyloxy) tetrahydrothiophene-1,1-dioxide (compound 7) was performed on a 500 equipped with a stirrer, a cooling tube, a thermometer and a dropping funnel. A four-necked flask with a mL capacity was charged with 200 mL of dichloromethane, and 3-hydroxycyclobutane (6.8 g, 50 mmol) and pyridine (4.7 g, 60 mmol) were added. Then, the reaction solution was cooled to -78 ° C, and phosphorus phosphonium chloride (23 g, 150 mmol) was added dropwise, and the temperature was raised to 27 ° C. While maintaining the temperature, the reaction solution was stirred for 2 hours, and then unnecessary components such as pyridine were removed by distillation. Then, 100 g of acetonitrile and sodium fluoride (0.42 g, 100 mmmol) were added. After the temperature was raised to 40 ° C, the reaction solution was stirred for 5 hours while maintaining the temperature, and then 100 g of water and 100 g of dichloromethane were added. Thereafter, the oil layer was concentrated to obtain 1.2 g of 3- (difluorophosphinooxy) tetrahydrothiophene-1,1-dioxide (Compound 7). The yield of compound 7 was 11% relative to 3-hydroxycyclobutane. The obtained compound 7 was confirmed to have a molecular weight of 220 by LC / MS spectrum.

2. Preparation of Non-Aqueous Electrolyte In the "2. Preparation of Non-Aqueous Electrolyte" in Example 1, except that Compound 1 was used instead of Compound 7, a non-aqueous electrolyte was prepared in the same manner.

(Comparative Example 1) A non-aqueous electrolytic solution was prepared in the same manner as in "2. Preparation of Non-Aqueous Electrolyte" except that Compound 1 was not added.

(Comparative Example 2) In the "2. Preparation of non-aqueous electrolyte solution" of Example 1, except that 1,3-propane sultone (PS) was used instead of compound 1, it was prepared in the same manner. Non-aqueous electrolyte.

(Comparative Example 3) In the "2. Preparation of non-aqueous electrolyte solution" of Example 1, except that vinylene carbonate (VC) was used instead of compound 1, a non-aqueous electrolyte solution was prepared in the same manner. .

(Comparative Example 4) A non-aqueous electrolytic solution was prepared in the same manner as in Comparative Example 3, except that the content ratio of vinylene carbonate (VC) was 2.0% by mass.

(Comparative Example 5) In the "2. Preparation of non-aqueous electrolytic solution" of Example 1, except that Compound 1 was used instead of fluoroethylene carbonate (FEC), a non-aqueous solution was prepared in the same manner Electrolyte.

(Comparative Example 6) A non-aqueous electrolytic solution was prepared in the same manner as in Comparative Example 5 except that the content ratio of fluoroethylene carbonate (FEC) was set to 2.0% by mass.

(Comparative Example 7) A non-aqueous electrolyte solution was prepared in the same manner as described in "2. Preparation of Non-Aqueous Electrolyte Solution" in Example 1 except that cyclamidine was used instead of compound 1.

(Production of non-aqueous electrolyte secondary battery) LiNi _1/3 Co _1/3 Mn _1/3 O ₂ as a positive electrode active material and carbon black as a conductivity imparting agent were dry-blended. The obtained mixture was uniformly dispersed in N-Methyl-2-Pyrrolidone (NMP) in which polyvinylidene fluoride (PVDF) was dissolved as a binder, so that Make slurry. The obtained slurry was applied to both sides of an aluminum metal foil (square, 20 μm thick). After removing NMP by drying, the whole was pressed to produce a positive electrode sheet having an aluminum metal foil as a positive electrode current collector and a positive electrode active material layer formed on both surfaces of the aluminum metal foil. The solid content ratio in the positive electrode sheet becomes a positive electrode active material in a mass ratio: a conductivity imparting agent: PVDF = 92: 5: 3.

The graphite powder as a negative electrode active material and carbon black as a conductivity imparting agent are dry-mixed. The obtained mixture, Styrene Butadiene Rubber (SBR) and Carboxy Methyl Cellulose (CMC) were uniformly dispersed in water to prepare a slurry. The obtained slurry was applied to one side of a copper foil (square, 10 μm thick). After the coating film is dried to remove water, the whole is pressed to produce a negative electrode sheet having a copper foil as a negative electrode current collector and a negative electrode active material layer formed on one surface of the copper foil. The solid content ratio of the negative electrode sheet becomes a negative electrode active material in terms of mass ratio: CMC: SBR = 98: 1: 1.

The negative electrode sheet produced above, a separator including polyethylene, a positive electrode sheet, a separator including polyethylene, and a negative electrode sheet were laminated in this order to produce a battery element. The battery element was inserted into the bag such that the ends of the positive electrode sheet and the negative electrode sheet protruded from the bag, which is a laminated film including aluminum (thickness: 40 μm) and a resin layer covering both sides of the aluminum. form. Next, each of the non-aqueous electrolytes obtained in the examples and comparative examples was poured into a bag. The pouch was vacuum-sealed to obtain a sheet-shaped non-aqueous electrolyte secondary battery. Further, in order to improve the adhesion between the electrodes, a sheet-shaped non-aqueous electrolyte secondary battery is sandwiched between glass plates and pressurized.

(Evaluation of initial resistance ratio) Each of the obtained non-aqueous electrolyte secondary batteries was charged to 4.2 V at 25 ° C. with a current corresponding to 0.2 C. The charged secondary battery was aged by maintaining it at 45 ° C. for 24 hours. Thereafter, discharge was performed at 25 ° C. to a current of 0.2 C to 3 V. Next, the battery was stabilized by repeating three cycles of charging to 4.2 V at a current corresponding to 0.2 C and discharging to 3 V at a current corresponding to 0.2 C. Thereafter, charge and discharge were performed at 1 C, and the discharge capacity was measured, and it was set to "initial capacity".

Furthermore, after the initial charge and discharge, the non-aqueous electrolyte secondary battery charged with electricity having a capacity of 50% of the initial capacity was measured at 25 ° C for an AC impedance, and the initial resistance (Ω) ". Table 1 shows the initial resistance ratio of each battery. The “initial resistance ratio” is a relative value of the resistance of each non-aqueous electrolyte secondary battery when the initial resistance (Ω) of Comparative Example 1 is set to 1.

(Evaluation of discharge capacity retention rate and resistance increase rate) For each non-aqueous electrolyte secondary battery after initial charge and discharge, set the charge rate to 1 C, the discharge rate to 1 C, the charge termination voltage to 4.2 V, And the discharge termination voltage was set to 3 V to perform a 200-cycle charge-discharge cycle test. Thereafter, charge and discharge were performed at 1 C to measure the discharge capacity, and this was set to "post-cycle capacity".

Furthermore, after the cycle test, the non-aqueous electrolyte secondary battery charged with a capacity of 50% of the capacity after the cycle was measured for an AC impedance at 25 ° C, and set it as "resistance after the cycle." (Ω) ". Table 1 shows the discharge capacity retention rate and the resistance increase rate of each battery. The "discharge capacity maintenance ratio" in Table 1 is a value calculated by the formula: (capacity after cycle) / (initial capacity). The "resistance increase rate" in Table 1 is a value calculated by the formula: (resistance after cycling) / (initial resistance).

(Evaluation of gas generation) A non-aqueous electrolyte solution of the same configuration including the electrolytes prepared in Examples and Comparative Examples was prepared separately from the batteries used in the evaluation of initial resistance, evaluation of discharge capacity retention rate, and resistance increase rate. Secondary battery. The battery was charged to 4.2 V at 25 ° C with a current equivalent to a charging rate of 0.2 C. The charged secondary battery was aged by maintaining it at 45 ° C. for 24 hours. Thereafter, discharge was performed at 25 ° C. to a current of 0.2 C to 3 V. Next, three cycles of charging to 4.2 V at a current corresponding to 0.2 C and discharging to 3 V at a current corresponding to 0.2 C were repeated to perform initial charge and discharge to stabilize the battery.

For the non-aqueous electrolyte secondary battery after initial charge and discharge, the volume of the battery was measured by the Archimedes method, and this was set as the "initial volume (cm ³ )" of the battery. Furthermore, after the battery was charged to 4.2 V at 1 C at 25 ° C, the battery was left at 60 ° C for 168 hours. Thereafter, the battery was cooled to 25 ° C. and discharged at 1 C to 3 V. For the battery, the battery using a volumetric Archimedes method, the "high temperature after storage volume (cm ^3)" which is set to the battery. Table 1 shows the "gas generation amount" of each battery. The "gas generation amount" is a value calculated by the formula: (volume after high temperature storage)-(initial volume).

[Table 1] [Industrial availability]

According to the present invention, it is possible to provide an additive for a non-aqueous electrolyte, which, when used in a non-aqueous electrolyte secondary battery, can improve battery characteristics such as long-term cycle characteristics, resistance characteristics, and initial resistance characteristics. In addition, according to the present invention, a nonaqueous electrolytic solution using the additive for a nonaqueous electrolytic solution and a power storage device using the nonaqueous electrolytic solution can be provided.

1‧‧‧Non-aqueous electrolyte secondary battery

2‧‧‧Positive collector

3‧‧‧ cathode active material layer

4‧‧‧Positive plate

5‧‧‧ negative current collector

6‧‧‧ Negative electrode active material layer

7‧‧‧ negative plate

8‧‧‧ Non-aqueous electrolyte

9‧‧‧ spacer

FIG. 1 is a cross-sectional view schematically showing an embodiment of a non-aqueous electrolyte secondary battery as an example of a power storage device.

Claims (9)

An additive for a non-aqueous electrolyte, comprising a compound represented by the following formula (1); In formula (1), R ¹ and R ² each independently represent a fluorine atom, an alkyl group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenyl group having 2 to 6 carbon atoms which may be substituted with a halogen atom, and Halogen atom-substituted alkynyl groups having 2 to 6 carbon atoms, aryl groups which may be substituted by halogen atoms, alkoxy groups which may be substituted by halogen atoms, alkoxy groups having 1 to 8 carbon atoms, and An alkenyloxy group, an alkynyloxy group having 2 to 6 carbon atoms which may be substituted with a halogen atom, or an aryloxy group which may be substituted with a halogen atom, and A represents a hydrogen atom or a halogen atom. The additive for a non-aqueous electrolyte according to item 1 of the scope of the patent application, wherein in the formula (1), R ¹ and R ² are each independently a fluorine atom and a alkoxy group having 1 to 3 carbon atoms which may be substituted with a halogen atom. Group, an alkenyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom, an alkynyloxy group having 2 to 4 carbon atoms which may be substituted with a halogen atom, or an aryloxy group which may be substituted with a halogen atom. The additive for non-aqueous electrolyte according to item 1 or item 2 of the scope of patent application, wherein in formula (1), A is a fluorine atom. A non-aqueous electrolyte contains the additive for a non-aqueous electrolyte, a non-aqueous solvent, and an electrolyte according to any one of items 1 to 3 of the scope of patent application. The non-aqueous electrolyte according to item 4 of the scope of patent application, wherein the non-aqueous solvent includes a cyclic carbonate and a chain carbonate. The non-aqueous electrolyte according to item 4 or item 5 of the patent application scope, wherein the electrolyte is an electrolyte containing a lithium salt. A power storage device includes the non-aqueous electrolyte according to any one of items 4 to 6 of the scope of patent application, and a positive electrode and a negative electrode. The power storage device according to item 7 of the scope of patent application, which is a lithium ion battery. The power storage device according to item 7 of the scope of patent application, which is a lithium ion capacitor.