JP2013149461A - Electrolytic solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic solution that shows excellent charge/discharge characteristics and provides a power storage device causing no temporary deterioration in spite of charging and discharging.SOLUTION: An electrolytic solution comprises an electrolyte, a solvent, and a solid electrolyte interface film. The solvent contains no water and the solid electrolyte interface film contains a specific sultone compound having a carbon-carbon double bond at one cyclic place.

Description

  The present invention relates to an electrolytic solution. More specifically, the electrolyte is suitable for application to an electricity storage device, particularly a lithium secondary battery, a lithium ion capacitor, etc., and can form a solid electrolyte interface film efficiently during the charging process of the electricity storage device. The present invention relates to a nonaqueous electrolytic solution containing an interface film forming agent.

In recent years, there has been a demand for an electricity storage device suitable as a driving power source for electric vehicles, electronic devices, and the like. In particular, lithium ion secondary batteries and lithium ion capacitors are expected as power storage devices having high voltage and high energy density.
An electricity storage device has a structure in which an electrolyte solution (electrolyte solution) containing an electrolyte and a solvent is sandwiched between a positive electrode and a negative electrode. As the electrolytic solution in the lithium ion secondary battery and the lithium ion capacitor, a non-aqueous electrolytic solution containing substantially no water is used. In this case, lithium salt such as LiPF ₆ or LiClO ₄ is generally used as the electrolyte;
As the solvent, for example, an organic solvent such as propylene carbonate or dimethyl carbonate is used. These organic solvents may be decomposed on the surface of the electrode (particularly, the negative electrode in the full cell) during the charge / discharge process of the electricity storage device to generate gas such as CO ₂ and impair the battery reaction, or the electrode active material ( In particular, the active material may be irreversibly reacted with the negative electrode active material in a full cell), and the electricity storage device using these solvents has a problem in durability.

In order to suppress such deterioration of the electricity storage device over time, a solid electrolyte interface film (SOI film) is commonly called on the surface of the electrode by reducing the electrolyte solvent during the initial charge of the electricity storage device. Various methods for forming the above have been proposed.
For example, Patent Documents 1 and 2 propose a method of adding a carbonate compound as an additive (SEI film forming agent) for forming an SEI film on the surface of an electrode active material. Patent Documents 3 to 6 propose a method of using a sultone-based compound as the SEI film forming agent. However, according to these SEI film forming agents, only a SEI film that is insufficient in quality and quantity is formed which is not dense and is not thick enough and covers only a part of the surface of the electrode active material. Therefore, the effect of suppressing the problems such as the decomposition of the electrolyte solvent and the alteration of the electrode active material is completely lacking. In addition, since the SEI film formed by these SEI film forming agents has a large Li ion migration resistance, there is a problem that the electrode resistance (impedance) at the time of charging and discharging of the electricity storage device increases. Furthermore, when the amount of addition of these SEI film forming agents is increased in an attempt to improve the effect of suppressing the above-described problems using known SEI film forming agents, the amount of the agent remaining in the electrolyte without involving in the formation of the SEI film. There is also a problem that this deteriorates with time due to charging and discharging and impairs battery characteristics.

Japanese Patent Application Laid-Open No. 08-45545 JP 2001-006729 A JP-A-62-100948 JP 2000-235866 A JP 2002-329528 A Special table 2011-519133 gazette

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrolytic solution that exhibits good charge / discharge characteristics and provides an electricity storage device that does not deteriorate over time due to charge / discharge. It is in.

The above objects and advantages of the present invention are as follows:
An electrolyte solution comprising an electrolyte, a solvent, and a solid electrolyte interface film forming agent,
The solvent does not contain water, and the solid electrolyte interface film forming agent has the following general formula (1)

(In formula (1), R ^{1 to} R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms. , N is an integer of 1 to 3, m is an integer of 0 to 3, provided that when a plurality of R ¹ , R ² , R ⁵ or R ⁶ are present, the plurality of R ¹ , R ² , R ⁵ or R ⁶ may be the same or different.)
It achieves by the said electrolyte solution characterized by including the compound represented by these.

According to the electrolytic solution of the present invention, there is provided an electrolytic solution that exhibits good charge / discharge characteristics and provides an electricity storage device that does not deteriorate with time due to charge / discharge.
Since the electrolytic solution of the present invention contains a SEI film forming agent having high SEI film formation efficiency, a good quality SEI film is efficiently formed even when the amount of the agent added is small. Thus, the problems of decomposition of the electrolyte solvent and alteration of the electrode active material in the prior art are suppressed. Furthermore, since the SEI film formed from the electrolytic solution of the present invention has a low Li ion migration resistance, an electricity storage device having a low electrode resistance can be obtained.

Hereinafter, preferred embodiments according to the present invention will be described in detail. It should be understood that the present invention is not limited only to the embodiments described below, and includes various modified examples that are implemented without departing from the scope of the present invention.
1. Electrolytic Solution As described above, the electrolytic solution of the present invention includes an electrolyte, a solvent, and a solid electrolyte interface film forming agent (hereinafter referred to as “SEI film forming agent”).

1-1. Electrolyte As the electrolyte in the present invention, although not particularly limited, when the electricity storage device is a lithium ion secondary battery or a lithium ion capacitor,
A known lithium salt can be preferably used.
Preferred examples of the electrolyte in the present invention, for example, lithium salt of a carboxylic acid having 2 to 30 carbon _{atoms, LiClO 4, LiBF 4, LiPF} 6, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4 , LiCl, LiBr, LiB (C ₂ H ₅ ) ₄ , LiCF ₃ SO ₃ , LiCH ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N and the like can be selected. At least one of the above can be used.
The carbon number in the lithium salt of the carboxylic acid is a number including the carbon of the carboxy group. Examples of the lithium salt of a carboxylic acid having 2 to 30 carbon atoms include lithium acetate, lithium propionate, lithium butyrate, lithium valerate, lithium caproate, lithium caprylate, lithium succinate, lithium glutarate, lithium adipate, and malon. Examples include lithium acid, lithium acrylate, lithium methacrylate, lithium maleate, lithium fumarate, lithium phthalate, lithium benzoate, lithium benzenetetracarboxylate, lithium naphthalenecarboxylate, lithium ethylenediaminetetraacetate, lithium ethylenediaminetriacetate, etc. be able to.
As the electrolyte in the present invention, it is particularly preferable to use at least one selected from LiBF ₄ and LiPF ₆ .

1-2. Solvent The solvent in the electrolytic solution of the present invention contains substantially no water. Here, “substantially free of water” means a low water content as a result of preventing water intrusion by the caution usually taken in the manufacture of electricity storage devices, and in a chemically strict sense H _It does not require that no ₂ O molecule is present in the solvent.
The content of water in the solvent in the present invention is preferably 1% by mass or less, more preferably 0.5% by mass or less, and further preferably 0.1% by mass or less.
Examples of the solvent in the electrolytic solution of the present invention include carbonate compounds such as propylene carbonate, ethylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and ethyl methyl carbonate;
Lactone compounds such as γ-butyl lactone;
Ester compounds such as methyl acetate, ethyl acetate, methyl propionate, ethyl propionate;
Ether compounds such as trimethoxymethane, 1,2-dimethoxyethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, ethoxymethoxyethane;
Examples thereof include sulfoxide compounds such as dimethyl sulfoxide, and at least one selected from these compounds can be used.

1-3. SEI film forming agent 1-3-1. Compound Represented by General Formula (1) The SEI film forming agent in the present invention contains a compound represented by the general formula (1) (hereinafter referred to as “compound (1)”). In the above formula (1), when m = 0, the oxygen atom constituting the ring is directly connected to the sp ² carbon having the group R ⁴ .
Compound (1) is a sultone compound having a carbon = carbon unsaturated bond in the cyclic structure. Since this carbon = carbon unsaturated bond is not adjacent to the sulfur atom, it is considered to be highly reactive. For this reason, it is considered that by adding a small amount of the compound (1) to the electrolytic solution, this rapidly undergoes electropolymerization on the active material surface during the initial charging process, thereby forming a dense SEI film on the entire surface of the active material. Since the SEI film formed from the compound (1) is dense and firm, it does not easily collapse even when charging / discharging of the electricity storage device is repeated, and is further formed when the compound (1) is added at a preferable usage rate described later. Since the SEI film covers the entire surface of the active material, the life of the electricity storage device is improved, and a decrease in charge / discharge capacity with time is suppressed.
On the other hand, since the SEI film is dense and firm and has low diffusion resistance of lithium ions, the electrode resistance of the electricity storage device can be maintained at a low value.
R ^{1 to} R ⁶ in the general formula (1) are each independently preferably a hydrogen atom, a fluorine atom, a methyl group, a trifluoromethyl group, or a phenyl group. n and m are each preferably 1.

Preferred specific examples of the compound (1) include butadiene-δ-sultone, isoprene-δ-sultone, 2,3-dimethylbutadiene-δ-sultone, piperylene-δ-sultone, 2-chlorobutadiene-δ-sultone, 2- Phenylbutadiene-δ-sultone, 2,3-diphenylbutadiene-δ-sultone, hexafluorobutadiene-δ-sultone, trifluoromethyl-2, -butadiene-δ-sultone, ditrifluoromethyl-2,3-butadiene-δ -Sultone etc. can be mentioned, At least 1 sort (s) selected from these can be used. The compound (1) is more preferably at least one selected from the group consisting of butadiene-δ-sultone, isoprene-δ-sultone, 2,3-dimethylbutadiene-δ-sultone, and piperylene-δ-sultone, Particularly preferred is at least one selected from the group consisting of isoprene-δ-sultone and 2,3-dimethylbutadiene-δ-sultone.
Such preferable compound (1) is, for example, the following formula (2):

(In formula (2), R ^{1 to} R ⁶ each have the same meaning as in general formula (1) above.)
It can be easily obtained by reacting a conjugated diene represented by the following (hereinafter referred to as “compound (2)”) with a sulfonating agent, preferably in an appropriate solvent.
The compound (2) is selected according to the structure of the desired compound (1). For example, butadiene, isoprene, 2,3-dimethylbutadiene, piperylene, 2-chlorobutadiene, 2-phenylbutadiene, 2,3-diphenylbutadiene , Hexafluorobutadiene, trifluoromethyl-2, -butadiene and ditrifluoromethyl-2,3-butadiene can be appropriately selected and used.
Examples of the sulfonating agent include sulfuric anhydride and a complex of sulfuric anhydride and an electron donating compound (1: 1 in molar ratio). Examples of the electron donating compound include ether compounds such as N, N-dimethylformamide, dioxane, dibutyl ether, tetrahydrofuran and diethyl ether;
Amine compounds such as pyridine, piperazine, trimethylamine, triethylamine, tributylamine;
Examples thereof include sulfides such as dimethyl sulfide and diethyl sulfide; and nitrile compounds such as acetonitrile, ethyl nitrile and propyl nitrile. Among these, at least one selected from N, N-dimethylformamide and dioxane is used. It is preferable to use it.

The use ratio of the sulfonating agent is preferably 0.5 to 2 moles, more preferably 0.7 to 1.5 moles as the use ratio in terms of anhydrous sulfuric acid with respect to 1 mole of the compound (2). Preferably, it is 0.9-1.1. When this value is less than 0.5 mol, the reaction yield decreases, while when it exceeds 2 mol, the proportion of the unreacted sulfonating agent increases, and the compound (1) obtained by the reaction changes in quality over time. Both are not preferred.
Examples of the solvent preferably used in the reaction of the compound (2) with the sulfonating agent include ether compounds such as dioxane, dibutyl ether, tetrahydrofuran, and diethyl ether;
Halogenated hydrocarbons such as chloroform, dichloroethane, tetrachloroethane, tetrachloroethylene, dichloromethane;
Nitro compounds such as nitromethane and nitrobenzene;
Liquid sulfur dioxide;
Aliphatic hydrocarbons such as propane, butane, pentane, hexane, and cyclohexane can be exemplified, and at least one selected from these can be used.
The use ratio of the solvent is preferably 100 to 2,000 parts by mass, and more preferably 300 to 1,000 parts by mass with respect to 100 parts by mass in total of the compound (2) and the sulfonating agent.
The reaction temperature is preferably -20 to 100 ° C, more preferably 0 to 50 ° C, and further preferably 10 to 30 ° C. The reaction time is preferably 1 to 5 hours, and more preferably 1.5 to 3 hours.
As described above, the compound (1) can be easily obtained.

1-3-2. Other SEI film forming agents In the electrolyte solution of the present invention, other SEI film forming agents can be used in combination with the compound (1) as long as the effects of the present invention are not impaired.
As other SEI film forming agents that can be used here, known agents that are known to have a high SEI film forming effect in the prior art can be used, such as ethylene sulfite, 1.3- Examples thereof include propane sultone, 1,4-butane sultone, γ-sultone, vinylene carbonate, and fluoroethylene carbonate, and at least one selected from these can be used.

1-4. Other Additives In the electrolytic solution of the present invention, other additives can be used in combination with the compound (1) as long as the effects of the present invention are not impaired.
Examples of other additives that can be used here include flame retardants, overcharge inhibitors, and leakage inhibitors. Examples of these include, as the flame retardant, for example, phosphorus compounds, phosphazene compounds and the like;
Examples of the overcharge preventing agent include aromatic compounds (such as biphenyl compounds and terphenyl compounds), redox shuttle agents, and the like;
Examples of the leakage preventing agent include a gelling agent, and at least one selected from these can be used.

1-5. Electrolytic Solution The electrolytic solution of the present invention contains the above-described electrolyte, solvent, and other additives and an SEI film forming agent as necessary.
The content (concentration) of the electrolyte in the electrolytic solution of the present invention is preferably 0.5 to 3 mol / liter, more preferably 0.7 to 2 mol / liter.
The content ratio of the compound (1) in the present invention is preferably 0.001 to 1 mol / liter, more preferably 0.005 to 0.8 mol / liter, and still more preferably with respect to the electrolytic solution. 0.01 to 0.5 mol / liter. By containing the compound (1) within this range, the electrolytic solution of the present invention can form a good SEI film at the time of initial charge, and the compound (unreacted in the electrolytic solution after film formation) The ratio of 1) can be reduced as much as possible. As a result, even if charge / discharge is repeated, the charge / discharge characteristics are not deteriorated, and an electricity storage device having excellent temporal durability can be manufactured.
When the SEI film forming agent in the electrolytic solution of the present invention contains the other SEI film forming agent together with the compound (1), the use ratio of the other SEI film forming agent is preferably relative to the electrolytic solution. It is 2 mol / liter or less, more preferably 0.5 mol / liter or less.

2. Electric storage device The electric storage device in the present invention comprises the above-described electrolytic solution of the present invention.
The electricity storage device in the present invention can be produced according to a conventional method using components such as known electrodes and separators together with the above-described electrolytic solution of the present invention. For example, a method in which a negative electrode and a positive electrode are overlapped with a separator, wound and folded in accordance with a desired battery shape, and stored in a battery container, and an electrolytic solution is injected into the battery container and sealed. Can be mentioned.
The shape of the battery can be an appropriate shape such as a coin shape, a cylindrical shape, a square shape, or a laminate shape.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. “Parts” in Examples and Comparative Examples are based on mass unless otherwise specified.
In the evaluation of the electricity storage device, a “half cell” using a lithium foil for the positive electrode was produced and the charge / discharge characteristics were evaluated. Evaluation of charge / discharge characteristics by “half-cell” is a general evaluation method performed in the industry in a laboratory.
The evaluation by the half cell does not directly reproduce the behavior of the full cell which is an actual product. However, since it is possible to easily determine whether the SEI film is efficiently formed by half cell evaluation, it is possible to predict the behavior when the same technique is applied to a full cell.

<Synthesis of SEI film forming agent>
Synthesis example 1
After replacing the 500 mL separable flask with nitrogen, 160 g of dehydrated dioxane was charged therein, and the liquid temperature was set to 15 ° C. While cooling so that the liquid temperature was maintained at 15 to 20 ° C., 20 g of sulfuric anhydride was added dropwise little by little using a syringe. After dripping the whole quantity of anhydrous sulfuric acid, it stirred for 10 minutes and obtained the solution containing an anhydrous sulfuric acid-dioxane complex. Thereafter, 17 g of isoprene was added while cooling the reaction system. During the isoprene addition, the liquid temperature temporarily increased to about 40 ° C., but was maintained at about 20 ° C. in general. Stirring was continued for 2 hours after the addition of isoprene.
Next, a bath set at 50 ° C. was attached to the flask, and about 80% of the dioxane used was removed under reduced pressure using a rotary evaporator to obtain a concentrated solution.
The total amount of the concentrated liquid and 100 g of 1,2-dichloroethane were put into a separatory funnel and subjected to liquid separation extraction, and the dichloroethane layer (lower layer) from which the target substance was extracted was taken out. Dichloroethane was removed from the dichloroethane layer under reduced pressure to obtain the desired isoprene-δ-sultone.
Synthesis example 2
In Synthesis Example 1, 2,3-dimethylbutadiene-δ-sultone was obtained in the same manner as in Synthesis Example 1 except that 20.5 g of 2,3-dimethylbutadiene was used instead of isoprene.

<Manufacture and evaluation of half cells>
Examples 1-5 and Comparative Examples 1-3
(1) Production of positive electrode (lithium electrode) A positive electrode was produced by punching out a lithium foil (made by Honjo Metal Co., Ltd.) having a thickness of 200 μm into a circle having a diameter of 15.95 mm using a lithium metal punch.
(2) Production of negative electrode Biaxial planetary mixer (product name "TK Hibismix 2P-03" manufactured by PRIMIX Corporation), 4 parts of polyvinylidene fluoride (PVDF) (solid content conversion), as a negative electrode active material 100 parts (in terms of solid content) and 80 parts of N-methylpyrrolidone (NMP) were added and stirred at 60 rpm for 1 hour. Then, after further adding 20 parts of NMP, using a stirring defoamer (product name “Awatori Nertaro” manufactured by Shinky Co., Ltd.) for 2 minutes at 200 rpm, then for 5 minutes at 1,800 rpm, A negative electrode slurry was prepared by stirring and mixing at 1,800 rpm for 1.5 minutes under vacuum.
Next, the negative electrode slurry prepared above was uniformly applied by a doctor blade method to the surface of a current collector made of copper foil having a thickness of 18 μm, and heated at 120 ° C. for 20 minutes to form a negative electrode active material layer. A negative electrode sheet was obtained. The negative electrode sheet was punched into a disk shape having a diameter of 16.16 mm to produce a negative electrode.

(3) Preparation of electrolyte solution The SEI film forming agent of the type described in Table 1 in a propylene carbonate solution of LiPF ₆ (concentration of 1.0 mol / liter), the concentration in the electrolyte solution being the value described in Table 1. The electrolyte solution was prepared by adding and mixing so that.
In Comparative Example 1, no SEI film forming agent was used.
(4) Manufacture of electricity storage device (half cell) In the glove box substituted with argon so that the dew point is -80 ° C. or less, the negative electrode manufactured in the above “(2) Manufacturing of negative electrode” is a bipolar coin cell (treasure). The product was placed on Izumi Co., Ltd. (trade name “HS Flat Cell”). Next, a separator made of a polypropylene porous membrane punched to a diameter of 24 mm (product name “Celguard # 2400” manufactured by Celgard Co., Ltd.) is placed, and further, the above “(3) electrolyte solution is used to prevent air from entering. After injecting 500 μL of the electrolytic solution prepared in “Preparation”, the positive electrode manufactured in “(1) Manufacturing of positive electrode (lithium electrode)” is placed, and the outer body of the bipolar coin cell is closed with a screw and sealed. By doing this, the half cell (electric storage device) of the lithium ion battery was manufactured.

(5) Evaluation of charge / discharge characteristics When the half cell produced above was left in a constant temperature bath at 25 ° C., the half cell was charged with a constant current (0.1 C), and the voltage became 0V. Was charged (cut off).
In this charging process, when it is possible to charge until the voltage becomes 0 V, it can be evaluated that the charging characteristic is “good”. On the other hand, when charging cannot be performed until the voltage reaches 0 V, the charging characteristics are evaluated as “bad”.
For battery cells that have been charged until the voltage reaches 0V, discharge is further started at a constant current (0.1C), and when the voltage reaches 3V, it is determined that the discharge is complete, and the discharge up to that point The volume was calculated. If the discharge capacity is 350 mAh / g or more, it can be determined that the discharge capacity is sufficiently high.
(6) Evaluation of electrode resistance The half cell after charging / discharging at 0.1 C in the above “(5) Evaluation of charging / discharging characteristics” is charged again with a cut-off voltage of 0 V at a current amount of 0.1 C. went. The recharged cell was subjected to EIS measurement (“Electrochemical Impedance Spectroscopy”, “Electrochemical Impedance Measurement”) using a module type potentiogalvanostat (product name: VMP3) manufactured by Bio-Logic Scientific Instruments. The measurement was performed at a frequency of 100 KHz to 0.1 Hz, a voltage amplitude of 3 mV, and a measurement temperature of 25 ° C. to obtain a Nyquist plot. The value of electrode resistance (impedance) was calculated from the value of Re (Z) when −Im (Z) of the arc of this Nyquist plot was 0Ω. When the impedance value is 300Ω or less, it can be determined that the electrode resistance characteristics are good.

Abbreviations of SEI film forming agents in Table 1 have the following meanings, respectively.
IS: isoprene-δ-sultone synthesized in Synthesis Example 1 DMBS: 2,3-dimethylbutadiene-δ-sultone synthesized in Synthesis Example 2 ES: ethylene sulfite (manufactured by Kishida Chemical Co., Ltd.)

Comparative Example 1 using an electrolytic solution containing no SEI film forming agent has “bad” charging characteristics, whereas Examples 1 to 5 using an electrolytic solution containing a predetermined SEI film forming agent of the present invention are used. All have good charge characteristics and a large discharge capacity.
In this regard, ethylene sulfite, which is a known SEI film forming agent, does not exhibit its effect at a low concentration of about 0.02 mol / liter (Comparative Example 2). When this concentration is 0.05 mol / liter, the charge characteristics are possible, but the discharge capacity is low (Comparative Example 3). In contrast, the predetermined SEI film forming agent of the present invention can exhibit its effect even at a low concentration, and surprisingly has a high discharge capacity (Examples 1 and 5). Furthermore, even if the usage ratio is increased, the battery characteristics are not impaired (Examples 2 to 4).
The difference in the effects described above between the known SEI film forming agent and the SEI film forming agent of the present invention is presumed to be based on the difference in the formation efficiency of the SEI film in the charging process. That is, the reason for the poor charging characteristics in Comparative Examples 1 and 2 is that the SEI film is not formed on the surface of the negative electrode (graphite) during the charging process (Comparative Example 1) or is insufficient (Comparative Example 2). Therefore, it is considered that lithium ions penetrate into the negative electrode active material layer while being solvated with propylene carbonate, and the layered structure of the negative electrode active material (graphite) is destroyed.

On the other hand, when the SEI film forming agent according to the present invention is used, the SEI film is efficiently formed in the charging process even at a low concentration. Therefore, desorption from lithium ions solvated on the surface of the SEI film is achieved. It is considered that normal charging is performed without the progress of the solvent and destruction of the negative electrode structure.
From the above in the half cell experiment, it can be expected that when the predetermined SEI film forming agent of the present invention is applied to a full cell, the SEI film is efficiently formed. Therefore, by using the predetermined SEI film forming agent of the present invention, when a known SEI film forming agent is used, generation of gas due to decomposition of the solvent on the surface of the active material, irreversible of the active material due to reaction with the solvent It is predicted that problems such as serious destruction will be solved.
Further, Examples 1 to 5 using the SEI film forming agent of the present invention all have low impedance and very good electrode resistance characteristics. Accordingly, it is predicted with a high degree of probability that an electricity storage device having extremely low electrode resistance can be obtained even when the SEI film forming agent of the present invention is applied to a full cell.

Claims (5)

An electrolyte solution comprising an electrolyte, a solvent, and a solid electrolyte interface film forming agent,
The solvent does not contain water, and the solid electrolyte interface film forming agent has the following general formula (1)

(In formula (1), R ^{1 to} R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms. , N is an integer of 1 to 3, m is an integer of 0 to 3, provided that when a plurality of R ¹ , R ² , R ⁵ or R ⁶ are present, the plurality of R ¹ , R ² , R ⁵ or R ⁶ may be the same or different.)
The said electrolyte solution characterized by including the compound represented by these.   2. The electrolytic solution according to claim 1, wherein a content ratio of the compound represented by the general formula (1) in the electrolytic solution is 0.001 to 1 mol / liter. Wherein the electrolyte is a lithium salt of a carboxylic acid having 2 to 30 carbon _{atoms, LiClO 4, LiBF 4, LiPF} 6, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB ( C ₂ H _{5) 4,} an _{LiCF 3 SO 3, LiCH 3 SO} 3, LiC 4 F 9 SO 3 and _Li (CF 3 _{SO 2)} at least one member selected from the group consisting of ₂ N, in claim 1 Electrolyte of description.   The electrical storage device provided with the electrolyte solution as described in any one of Claims 1-3. The following general formula (1)

(In formula (1), R ^{1 to} R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a fluoroalkyl group having 1 to 12 carbon atoms, or an aryl group having 6 to 18 carbon atoms. , N is an integer of 1 to 3, m is an integer of 0 to 3, provided that when a plurality of R ¹ , R ² , R ⁵ or R ⁶ are present, the plurality of R ¹ , R ² , R ⁵ or R ⁶ may be the same or different.)
A solid electrolyte interface film-forming agent comprising a compound represented by the formula: