JP2012119092A - Nonaqueous electrolytic solution, electrode, and electrochemical device comprising nonaqueous electrolytic solution and electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolytic solution improving safety of an electrochemical device by reducing the heating value in an electrode active material layer while maintaining the discharge capacity, an electrode, and an electrochemical device comprising the nonaqueous electrolytic solution and the electrode.SOLUTION: A nonaqueous electrolytic solution contains: a compound represented by the formula (I) in which at least two of three hydrogen atoms in phosphoric acid are substituted by a (meth)acryloyloxyalkyl group; a nonaqueous solvent; and an electrolyte. In the formula (I), Xand Xrepresent a hydrogen atom or a methyl group, and Xand Xmay be the same or different; Rrepresents a hydrogen atom, a C1-C24 hydrocarbon group, or a specific (meth)acryloyloxyalkyl group; and a and b represent an integer of 1 to 10, and a and b may be the same or different.

Description

  The present invention relates to a non-aqueous electrolyte solution, an electrode, and an electrochemical device including the non-aqueous electrolyte solution and the electrode.

  In order to improve the performance of electrochemical devices using non-aqueous electrolytes, such as capacity, storage characteristics, cycle characteristics, safety, etc., addition of organic compounds such as methyl methacrylate to the electrolyte has been studied (patent) Reference 1-6).

JP 2000-223154 A JP 2000-149989 A JP 2006-216276 A JP 2010-027616 A JP 2001-015158 A JP 2009-123498 A

  By the way, in terms of safety, an electrochemical device using a non-aqueous electrolytic solution is a material that is generally flammable, such as an electrode active material and an electrolytic solution. If the temperature rises (abnormal heat generation), there is a risk that the electrochemical device body burns.

  In order to solve such problems, for example, the use of olivine-type lithium iron phosphate, lithium titanate, or the like as the electrode active material, or the use of, for example, an ionic liquid as the electrolytic solution has been studied. However, employing these materials is not preferable in terms of energy density reduction and cost. In addition, an additive is added to the electrolyte solution to reduce abnormal heat generation of the electrochemical device. However, paying attention to heat generation in the electrode active material layer under a high temperature environment, the heat generation amount is suppressed. Has not yet been fully studied.

  Therefore, the present invention includes a non-aqueous electrolyte solution, an electrode, and the non-aqueous electrolyte solution and the electrode that reduce the calorific value in the electrode active material layer and improve the safety of the electrochemical device while maintaining the discharge capacity. An object is to provide an electrochemical device.

式（Ｉ）中、Ｘ^１及びＸ^２は水素原子又はメチル基を示し、Ｘ^１及びＸ^２はそれぞれ同一でも異なっていてもよく、Ｒ¹は水素原子、炭素数１〜２４の炭化水素基又は、式（ＩＩ）で表される（メタ）アクリロイルオキシアルキル基を示し、ａ及びｂは１〜１０の整数を示し、ａ及びｂはそれぞれ同一であっても異なっていてもよい。

式（ＩＩ）中、Ｘ^３は水素原子又はメチル基を示し、ｃは１〜１０の整数を示す。 The present invention relates to a compound represented by the formula (I) in which two or more hydrogen atoms among three hydrogen atoms of phosphoric acid are substituted with a (meth) acryloyloxyalkyl group, a non-aqueous solvent, an electrolyte, A non-aqueous electrolyte solution is provided.

In formula (I), X ¹ and X ² represent a hydrogen atom or a methyl group, X ¹ and X ² may be the same or different, and R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms. Or the (meth) acryloyloxyalkyl group represented by Formula (II) is shown, a and b show the integer of 1-10, and a and b may be the same or different, respectively.

In formula (II), X ³ represents a hydrogen atom or a methyl group, and c represents an integer of 1 to 10.

  When the non-aqueous electrolyte contains the compound represented by the above formula (I), the amount of heat generated in the electrode active material layer in a high temperature environment can be reduced while maintaining the discharge capacity. Thereby, the temperature rise of an electrochemical device can be suppressed and the safety | security of an electrochemical device can be improved.

式（ＩＩＩ）中、Ｘ^４は水素原子又はメチル基を示し、ｄは１〜１０の整数を示す。 Here, this invention may further contain the compound represented by Formula (III).

In formula (III), X ⁴ represents a hydrogen atom or a methyl group, and d represents an integer of 1 to 10.

  Further, the content of the compound represented by the formula (I) is preferably 0.0008% by mass to 4.0% by mass, and more preferably 0.008% by mass to 3.0% by mass. .

  When the content of the compound represented by the formula (I) is less than 0.0008% by mass in the non-aqueous electrolyte solution of the present invention, the effect of reducing the calorific value in the electrode active material layer tends to be insufficient. On the other hand, when the amount is more than 4.0% by mass, the effect of reducing the amount of heat generated in the electrode active material layer is improved, but the discharge capacity tends to decrease. By containing the compound represented by the formula (I) in an amount of 0.0008% by mass to 4.0% by mass, the effect of the present invention can be obtained more reliably. Moreover, the effect of the said invention can be acquired more reliably by containing the compound represented by Formula (I) 0.008 mass% or more and 3.0 mass% or less.

式（Ｉ）中、Ｘ^１及びＸ^２は水素原子又はメチル基を示し、Ｘ^１及びＸ^２はそれぞれ同一でも異なっていてもよく、Ｒ¹は水素原子、炭素数１〜２４の炭化水素基又は、式（ＩＩ）で表される（メタ）アクリロイルオキシアルキル基を示し、ａ及びｂは１〜１０の整数を示し、ａ及びｂはそれぞれ同一であっても異なっていてもよい。

式（ＩＩ）中、Ｘ^３は水素原子又はメチル基を示し、ｃは１〜１０の整数を示す。 The present invention also includes a current collector and an active material layer including an active material, a binder, and a polymer having a structural unit derived from the compound represented by formula (I) and formed on the surface of the current collector. An electrode is provided.

In formula (I), X ¹ and X ² represent a hydrogen atom or a methyl group, X ¹ and X ² may be the same or different, and R ¹ is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms. Or the (meth) acryloyloxyalkyl group represented by Formula (II) is shown, a and b show the integer of 1-10, and a and b may be the same or different, respectively.

In formula (II), X ³ represents a hydrogen atom or a methyl group, and c represents an integer of 1 to 10.

  As a result, it is possible to obtain an electrode in which the discharge capacity is sufficiently maintained and the calorific value in a high temperature environment is reduced.

式（ＩＩＩ）中、Ｘ^４は水素原子又はメチル基を示し、ｄは１〜１０の整数を示す。 In the electrode of the present invention, the polymer may further have a structural unit derived from the compound represented by the formula (III).

In formula (III), X ⁴ represents a hydrogen atom or a methyl group, and d represents an integer of 1 to 10.

  Moreover, this invention provides an electrochemical device provided with said non-aqueous electrolyte solution, and an electrochemical device provided with said electrode.

  Thereby, an electrochemical device with improved safety can be obtained.

  According to the present invention, a non-aqueous electrolyte solution, an electrode, and a non-aqueous electrolyte solution and an electrode that reduce the calorific value in the electrode active material layer and improve the safety of the electrochemical device while maintaining the discharge capacity. An electrochemical device can be provided.

FIG. 1 is a schematic cross-sectional view showing an electrochemical device according to this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In addition, the dimensional ratio of drawing is not restricted to the ratio of illustration.

First, the non-aqueous electrolyte used for the electrochemical device according to this embodiment will be described.
[Non-aqueous electrolyte]
The non-aqueous electrolyte solution of the present invention includes a phosphate represented by the formula (I) in which two or more hydrogen atoms among three hydrogen atoms of phosphoric acid are substituted with a (meth) acryloyloxyalkyl group; A non-aqueous solvent and an electrolyte.

In formula (I), X ¹ and X ² represent a hydrogen atom or a methyl group, and X ¹ and X ² may be the same or different. R ¹ represents a hydrogen atom, a hydrocarbon group having 1 to 24 carbon atoms, or a (meth) acryloyloxyalkyl group represented by the formula (II). Examples of the hydrocarbon group having 1 to 24 carbon atoms include a linear alkyl group, a branched alkyl group, a cycloalkyl group, an aryl group, a group in which a linear alkylene group or a branched alkylene group is bonded to a cycloalkyl group, and a cycloalkylene group. Is a group in which a linear alkyl group or a branched alkyl group is bonded, a linear alkylene group, a branched alkylene group, or a group in which a cycloalkylene group is bonded to an aryl group, an arylene group is a linear alkyl group, a branched alkyl group, or a cycloalkyl And a group bonded to the group. The hydrogen atom bonded to the carbon skeleton in these hydrocarbon groups may be substituted with a fluorine atom. a and b represent an integer of 1 to 10, and a and b may be the same or different. In the present invention, the (meth) acryloyloxy group includes an acryloyloxy group and a methacryloyloxy group.

In formula (II), X ³ represents a hydrogen atom or a methyl group, and c represents an integer of 1 to 10.

In R ¹ , the linear or branched alkyl group includes, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl , Nonadecyl, icosyl, henicosyl, docosyl, tricosyl, and tetracosyl linear or branched alkyl groups.

In R ¹ , as the cycloalkyl group, for example, cyclomethyl, cycloethyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, Examples include cyclopentadecyl, cyclohexadecyl, cycloheptadecyl, cyclooctadecyl, cyclononadecyl, cycloicosyl, cyclohenicosyl, cyclodocosyl, cyclotricosyl, and cyclotetracosyl.

In R ¹ , examples of the aryl group include a phenyl group and a naphthyl group.

In R ¹ , examples of the group in which a linear alkylene group or branched alkylene group and a cycloalkyl group are bonded include, for example, a group in which at least one hydrogen atom has been removed from the linear alkyl group or branched alkyl group, and the cycloalkyl group described above. Examples include groups in which an alkyl group is bonded and the total carbon number of the carbon skeleton of the group is in the range of 1 to 24.

In R ¹ , examples of the group in which a cycloalkylene group and a linear alkyl group or branched alkyl group are bonded include, for example, a group obtained by removing at least one hydrogen atom from the cycloalkyl group, and the linear alkyl group or branched group. Examples include groups in which an alkyl group is bonded and the total carbon number of the carbon skeleton of the group is in the range of 1 to 24.

In R ¹ , examples of the group in which a linear alkylene group, branched alkylene group, or cycloalkylene group is bonded to an aryl group include, for example, at least one hydrogen atom from the above linear alkyl group, branched alkyl group, or cycloalkyl group. Examples include groups in which the taken group is bonded to the aryl group, and the total carbon number of the carbon skeleton of the group is in the range of 1 to 24. Specific examples include a benzyl group and a trityl group.

In R ¹ , when the arylene group is a group in which a linear alkyl group, a branched alkyl group, or a cycloalkyl group is bonded, a group in which at least one hydrogen atom is removed from the aryl group, and the linear alkyl group , A branched alkyl group, or a cycloalkyl group, and the total carbon number of the carbon skeleton of the group is in the range of 1 to 24. Specific examples include a tolyl group and a xylyl group.

R ¹ is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, and particularly preferably a hydrogen atom. The hydrocarbon group having 1 to 10 carbon atoms is preferably a linear alkyl group, a branched alkyl group, a cycloalkyl group, or a group in which a cycloalkylene group is bonded to a linear alkyl group or a branched alkyl group. A branched alkyl group or a cycloalkyl group is more preferred.

As the phosphate represented by the formula (I), for example, when R ¹ is a hydrogen atom, a and b are the same, and X ¹ and X ² are the same, hydrogen phosphate = bis [ (Meth) acryloyloxymethyl], hydrogen phosphate = bis [2-((meth) acryloyloxy) ethyl], hydrogen phosphate = bis [3-((meth) acryloyloxy) propyl], hydrogen phosphate = bis [ 4-((meth) acryloyloxy) butyl], hydrogen phosphate = bis [5-((meth) acryloyloxy) pentyl], hydrogen phosphate = bis [6-((meth) acryloyloxy) hexyl], phosphoric acid Hydrogen = bis [7-((meth) acryloyloxy) heptyl], hydrogen phosphate = bis [8-((meth) acryloyloxy) octyl], hydrogen phosphate = bis [9-((meth) Like ((meth) acryloyloxy) decyl] is - acryloyloxy) nonyl], hydrogen phosphate = bis [10.

In addition, when R ¹ is a hydrogen atom, a and b are different, and X ¹ and X ² are the same or different from each other, examples of the phosphate represented by the formula (I) include hydrogen phosphate = [ (Meth) acryloyloxymethyl] [2-((meth) acryloyloxy) ethyl], hydrogen phosphate = [(meth) acryloyloxymethyl] [3-((meth) acryloyloxy) propyl], hydrogen phosphate = [ 2-((meth) acryloyloxy) ethyl] [4-((meth) acryloyloxy) butyl], hydrogen phosphate = [2-((meth) acryloyloxy) ethyl] [8-((meth) acryloyloxy) Octyl], hydrogen phosphate = [3-((meth) acryloyloxy) propyl] [10-((meth) acryloyloxy) decyl].

In addition, when R ¹ is a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group, or a cycloalkyl group, a and b are the same, and X ¹ and X ² are the same, Examples of the phosphate represented by I) include methyl phosphate = bis [(meth) acryloyloxymethyl], ethyl phosphate = bis [2-((meth) acryloyloxy) ethyl], propyl phosphate = bis [2-((meth) acryloyloxy) ethyl], isopropyl phosphate = bis [2-((meth) acryloyloxy) ethyl], butyl phosphate = bis [4-((meth) acryloyloxy) butyl], phosphorus Acid tert-butyl = bis [2-((meth) acryloyloxy) ethyl], pentyl phosphate = bis [2-((meth) acryloyloxy) ethyl], phosphorus Cyclopentyl = bis [2-((meth) acryloyloxy) ethyl], hexyl phosphate = bis [3-((meth) acryloyloxy) propyl], cyclohexyl phosphate = bis [3-((meth) acryloyloxy) ) Propyl], heptyl phosphate = bis [6-((meth) acryloyloxy) hexyl], octyl phosphate = bis [3-((meth) acryloyloxy) propyl], nonyl phosphate = bis [2-(( Meth) acryloyloxy) ethyl], decyl phosphate = bis [(meth) acryloyloxymethyl].

In addition, when R ¹ is a linear alkyl group having 1 to 10 carbon atoms, a branched alkyl group, or a cycloalkyl group, a and b are different, and X ¹ and X ² are the same or different from each other, formula (I Examples of the phosphate represented by) include methyl phosphate = [(meth) acryloyloxymethyl] [2-((meth) acryloyloxy) ethyl], ethyl phosphate = [2-((meth) acryloyloxy). ) Ethyl] [3-((meth) acryloyloxy) propyl], propyl phosphate = [2-((meth) acryloyloxy) ethyl] [4-((meth) acryloyloxy) butyl], propyl phosphate = [ 2-((meth) acryloyloxy) ethyl] [5-((meth) acryloyloxy) pentyl], butyl phosphate = [4-((meth) acryloyl) Xyl) butyl] [2-((meth) acryloyloxy) ethyl], tert-butyl phosphate = [2-((meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], phosphoric acid Pentyl = [2-((meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], cyclopentyl phosphate = [2-((meth) acryloyloxy) ethyl] [4-((meth) Acryloyloxy) butyl], hexyl phosphate = [2-((meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], cyclohexyl phosphate = [3-((meth) acryloyloxy) ) Propyl] [4-((meth) acryloyloxy) butyl], heptyl phosphate = [(meth) acryloyloxime [4-((meth) acryloyloxy) butyl], octyl phosphate = [2-((meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], nonyl phosphate = [2 -((Meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], decyl phosphate = [(meth) acryloyloxymethyl] [3-((meth) acryloyloxy) propyl] .

When R ¹ is a (meth) acryloyloxyalkyl group represented by the formula (II), a, b and c are the same and X ¹ , X ² and X ³ are the same, Examples of the phosphate represented by the formula (I) include phosphoric acid = tris [(meth) acryloyloxymethyl], phosphoric acid = tris [2-((meth) acryloyloxy) ethyl], phosphoric acid = tris [ 3-[[Meth] acryloyloxy] propyl], phosphoric acid = tris [4-((meth) acryloyloxy) butyl], phosphoric acid = tris [5-((meth) acryloyloxy) pentyl], phosphoric acid = tris [6-((meth) acryloyloxy) hexyl], phosphoric acid = tris [7-((meth) acryloyloxy) heptyl], phosphoric acid = tris [8-((meth) acryloyl) Carboxymethyl) octyl] phosphate = tris [9 - ((meth) acryloyloxy) nonyl], phosphoric acid = Tris [10 - like ((meth) acryloyloxy) decyl] is.

In addition, when R ¹ is a (meth) acryloyloxyalkyl group represented by the formula (II), a, b, and c are different and X ¹ , X ² , and X ³ are the same or different, Examples of the phosphate represented by I) include phosphoric acid = [(meth) acryloyloxymethyl] [2-((meth) acryloyloxy) ethyl] [3-((meth) acryloyloxy) propyl], phosphorus Acid = [(meth) acryloyloxymethyl] [2-((meth) acryloyloxy) ethyl] [4-((meth) acryloyloxy) butyl], phosphoric acid = [(meth) acryloyloxymethyl] [2- ( (Meth) acryloyloxy) ethyl] [7-((meth) acryloyloxy) heptyl], phosphoric acid = [(meth) acryloyloxymethyl] [2-((me ) Acryloyloxy) ethyl] [8 - ((meth) acryloyloxy) octyl] like.

The phosphate represented by the formula (I) preferably has a low molecular weight from the viewpoint of solubility in the electrolytic solution. Among the phosphates represented by the formula (I), R ¹ is a hydrogen atom. More preferably, a and b are each an integer of 1 to 5, more preferably an integer of 1 to 3, and particularly preferably a and b are the same. Among them, hydrogen phosphate = bis [(meth) acryloyloxymethyl] and hydrogen phosphate = bis [2- (meth) acryloyloxy) ethyl] are particularly preferable.

  In the present invention, the phosphate represented by the formula (I) is preferably contained in an amount of 0.0008% by mass to 4.0% by mass, and preferably 0.008% by mass to 3.0% by mass. More preferably, it is more preferably 0.016% by mass to 2.5% by mass, particularly preferably 0.04% by mass to 1.0% by mass, and more preferably 0.04% by mass to 0.5% by mass. It is more preferable to contain the following.

  In the non-aqueous electrolyte of the present invention, if the content of the phosphate represented by the formula (I) is less than 0.0008% by mass, the effect of reducing the calorific value in the electrode active material layer tends to be insufficient. is there. On the other hand, when the amount is more than 4.0% by mass, the effect of reducing the amount of heat generated in the electrode active material layer is improved, but the discharge capacity tends to decrease. By containing 0.0008 mass% or more and 4.0 mass% or less of the phosphate represented by Formula (I), the effect of the said invention can be acquired more reliably.

  Here, the present invention can further include a phosphate represented by the formula (III).

［式（ＩＩＩ）中、Ｘ^４は水素原子又はメチル基を示し、ｄは１〜１０の整数を示す。］

[In Formula (III), X ⁴ represents a hydrogen atom or a methyl group, and d represents an integer of 1 to 10. ]

  Examples of the phosphate represented by the formula (III) include (meth) acryloyloxymethyl phosphate, 2-((meth) acryloyloxy) ethyl phosphate, 3-((meth) acryloyloxy) propyl phosphate, 4-((meth) acryloyloxy) butyl phosphate, 5-((meth) acryloyloxy) pentyl phosphate, 6-((meth) acryloyloxy) hexyl phosphate, 7-((meth) acryloyloxy) phosphate Examples include heptyl, 8-((meth) acryloyloxy) octyl phosphate, 9-((meth) acryloyloxy) nonyl phosphate, and 10-((meth) acryloyloxy) decyl phosphate.

  Among the phosphates represented by the formula (III), d is preferably an integer of 1 to 5, more preferably an integer of 1 to 3, and of these, phosphoric acid (meth) acryloyloxymethyl, phosphoric acid 2 -(Meth) acryloyloxyethyl is particularly preferred.

  The phosphate represented by the formula (III) is, for example, in mass ratio, 0.0 to 0.5 times or 0.001 to 0.00 with respect to the phosphate represented by the formula (I). It can be contained in the electrolyte so as to be 22 times or 0.01 to 0.13 times. In the present invention, the phosphate represented by the formula (III) is not an essential component, but the phosphate represented by the formula (I) which is an essential component is usually a phosphorus represented by the formula (III). It exists in equilibrium with the acid salt and is difficult to isolate. Therefore, the phosphate represented by the formula (I) is usually present in a phosphoric acid aqueous solution diluted to 0.01 to 10% together with the phosphate represented by the formula (III) in the above ratio. (For example, (trade name) P-2M, manufactured by Kyoeisha Chemical Co., Ltd.), and by producing an electrolytic solution using such a solution, the formula of the above ratio is also included in the electrolytic solution according to the present invention. The phosphate represented by (III) will be present.

  When the non-aqueous electrolyte contains the phosphate represented by the above formula (I), the electrochemical device using the non-aqueous electrolyte is an electrode active material layer in a high-temperature environment while maintaining the discharge capacity. The amount of heat generated in can be reduced. Thereby, the temperature rise of an electrochemical device can be suppressed and the safety | security of an electrochemical device can be improved.

As the electrolyte, when the electrochemical device is a lithium secondary battery, a lithium salt is used. Examples of the lithium salt include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CF ₂ SO ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN _{(CF 3 CF 2 SO 2)} 2, LiN (CF 3 SO 2) (C 4 F 9 SO 2), LiN (CF 3 CF 2 CO) 2 , and the like.

When the electrochemical device is an electric double layer capacitor, for example, a quaternary ammonium salt such as tetraethylammonium tetrafluoroborate (TEA ⁺ BF ₄ ⁻ ) or triethyl monomethyl ammonium tetrafluoroborate (TEMA ⁺ BF ₄ ⁻ ) is used. An electrolytic solution dissolved in an organic solvent is used.

  In addition, these salts may be used individually by 1 type, and may use 2 or more types together.

  Moreover, as an organic solvent, when it includes the phosphate represented by the above formula (I), and the phosphate represented by the above formula (III), the phosphate represented by the above formula (III), Moreover, as long as it can dissolve the electrolyte, a solvent used in a known electrochemical device can be used. For example, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, γ-valerolactone, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxylene, 4-methyl-1,3 -Dixylene, methyl formate, methyl acetate, methyl propionate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, acetonitrile, sulfolane, 2-methyl sulfolane, dimethyl sulfoxide, N, N-dimethylformamide, N-methyloxazolidinone, etc. . These solvents can be used alone or in combination. Moreover, you may add about the amount of additives, such as vinyl carbonate and vinylene carbonate.

  The nonaqueous electrolytic solution of the present invention may be gelled by adding a polymer or the like as long as the effects of the present invention can be obtained.

  Subsequently, the electrode and the electrochemical device according to the present embodiment will be described with reference to FIG. Specifically, the case where the electrochemical device is a lithium secondary battery will be described.

[Lithium ion secondary battery]
The lithium ion secondary battery 100 mainly includes a laminate 30, a case 50 that accommodates the laminate 30 in a sealed state, and a pair of leads 60 and 62 connected to the laminate 30.

  The laminated body 30 is configured such that a pair of the positive electrode 10 and the negative electrode 20 are opposed to each other with the separator 18 interposed therebetween. The positive electrode 10 is obtained by providing a positive electrode active material layer 14 on a plate-like (film-like) positive electrode current collector 12. The negative electrode 20 is obtained by providing a negative electrode active material layer 24 on a plate-like (film-like) negative electrode current collector 22. The positive electrode active material layer 14 and the negative electrode active material layer 24 are in contact with both sides of the separator 18. Leads 60 and 62 are connected to the end portions of the positive electrode current collector 12 and the negative electrode current collector 22, respectively, and the end portions of the leads 60 and 62 extend to the outside of the case 50.

  Hereinafter, the positive electrode 10 and the negative electrode 20 are collectively referred to as electrodes 10 and 20, and the positive electrode current collector 12 and the negative electrode current collector 22 are collectively referred to as current collectors 12 and 22, and the positive electrode active material layer 14 and the negative electrode The active material layers 24 are collectively referred to as active material layers 14 and 24.

[electrode]
The electrodes 10 and 20 will be specifically described. The electrodes 10 and 20 include current collectors 12 and 22, and active material layers 14 and 24 containing active materials and binders formed on the surfaces of the current collectors 12 and 22, and the active material layer further includes the above A polymer having a structural unit derived from phosphoric acid represented by the formula (I) is included. The polymer preferably further has a phosphate-derived structural unit represented by the formula (III).

(Positive electrode 10)
The positive electrode current collector 12 may be a conductive plate material, and for example, a thin metal plate of aluminum, copper, or nickel foil can be used.
The positive electrode active material layer 14 includes the active material according to the present embodiment, a binder, and a conductive material in an amount necessary.

  The binder bonds the active materials to each other and bonds the active material to the positive electrode current collector 12.

The positive electrode active material may be any compound that contains lithium ions and can occlude and release lithium ions. For example, LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , Li (Co _x Ni _y Mn _z ) O ₂ Li-containing metal oxides such as Li (Ni _x Co _y Al _z ) O ₂ , Li ( _M n _x Al _y ) ₂ O ₄ , Li [Li _w Mn _x Ni _y Co _z ] O ₂ , LiVOPO ₄ , LiFePO ₄ Is mentioned.

  The material of the binder is not particularly limited as long as the above-described bonding is possible. For example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene. -Perfluoroalkyl vinyl ether copolymer (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polyvinyl fluoride ( And a phosphorus resin such as PVF).

  In addition to the above, as the binder, for example, vinylidene fluoride-hexafluoropropylene phosphorubber (VDF-HFP phosphorubber), vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene phosphorubber (VDF-HFP-TFE phosphorubber) ), Vinylidene fluoride-pentafluoropropylene phosphorus rubber (VDF-PFP phosphorus rubber), vinylidene fluoride-pentafluoropropylene-tetrafluoroethylene phosphorus rubber (VDF-PFP-TFE phosphorus rubber), vinylidene fluoride-perfluoromethyl vinyl ether -Tetrafluoroethylene phosphorus rubber (VDF-PFMVE-TFE phosphorus rubber), vinylidene fluoride-chlorotrifluoroethylene phosphorus rubber (VDF-CT E system Ringomu) may be used vinylidene fluoride-based Ringomu such.

  In addition to the above, for example, polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide, cellulose, styrene / butadiene rubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber, and the like may be used as the binder. Also, thermoplastic elastomeric polymers such as styrene / butadiene / styrene block copolymers, hydrogenated products thereof, styrene / ethylene / butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers, and hydrogenated products thereof. May be used. Further, syndiotactic 1,2-polybutadiene, ethylene / vinyl acetate copolymer, propylene / α-olefin (carbon number 2 to 12) copolymer may be used.

  Alternatively, an electron conductive conductive polymer or an ion conductive conductive polymer may be used as the binder. Examples of the electron conductive conductive polymer include polyacetylene. In this case, since the binder also functions as a conductive material, it is not necessary to add a conductive material.

As the ion-conductive conductive polymer, for example, those having ion conductivity such as lithium ion can be used. For example, polymer compounds (polyether-based polymer compounds such as polyethylene oxide and polypropylene oxide) A crosslinked polymer of a polyether compound, polyepichlorohydrin, polyphosphazene, polysiloxane, polyvinylpyrrolidone, polyvinylidene carbonate, polyacrylonitrile, etc.) monomers, and LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiCl, LiBr, Examples include Li (CF ₃ SO ₂ ) ₂ N, LiN (C ₂ F ₅ SO ₂ ) ₂ lithium salt, or a composite of alkali metal salt mainly composed of lithium. Examples of the polymerization initiator used for the combination include a photopolymerization initiator or a thermal polymerization initiator that is compatible with the above-described monomer.

  It is preferable that the content rate of the binder contained in the positive electrode active material layer 14 is 0.5-6 mass% on the basis of the mass of an active material layer. When the binder content is less than 0.5% by mass, the amount of the binder is too small and a tendency to fail to form a strong active material layer increases. Moreover, when the content rate of a binder exceeds 6 mass%, the quantity of the binder which does not contribute to an electrical capacity will increase, and the tendency for it to become difficult to obtain sufficient volume energy density becomes large. In this case, particularly, when the electronic conductivity of the binder is low, the electric resistance of the active material layer is increased, and there is a tendency that a sufficient electric capacity cannot be obtained.

  Examples of the conductive material include carbon powder such as carbon black, carbon nanotube, carbon material, fine metal powder such as copper, nickel, stainless steel and iron, a mixture of carbon material and fine metal powder, and conductive oxide such as ITO. It is done.

(Negative electrode 20)
The negative electrode current collector 22 may be a conductive plate material, and for example, a thin metal plate of aluminum, copper, or nickel foil can be used.
The negative electrode active material may be any compound that can occlude and release thium ions, and known negative electrode active materials for batteries can be used. Examples of the negative electrode active material include carbon materials such as graphite (natural graphite, artificial graphite) capable of inserting and extracting lithium ions, carbon nanotubes, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, Al, Si, and the like. And particles containing a metal that can be combined with lithium such as Sn, an amorphous compound mainly composed of an oxide such as SiO ₂ and SnO ₂ , lithium titanate (Li ₄ Ti ₅ O ₁₂ ), and the like. .
As the binder and the conductive material, the same materials as those for the positive electrode can be used.

Next, a method for manufacturing the electrodes 10 and 20 according to this embodiment will be described.
(Method for manufacturing electrodes 10 and 20)
The method for manufacturing the electrodes 10 and 20 according to the present embodiment includes a step of applying a coating material, which is a raw material of the electrode active material layers 14 and 24, onto the aggregate (hereinafter, also referred to as “coating step”), and a collector. The step of removing the solvent in the paint applied on the electric body to form an electrode active material layer (hereinafter sometimes referred to as “solvent removal step”), and the surface of the electrode active material layer, A step of forming a polymer having a phosphate-derived structural unit represented by I) (hereinafter also referred to as “polymer forming step”).

(Coating process)
An application process for applying the paint to the current collectors 12 and 22 will be described. The paint contains the active material, a binder, and a solvent. In addition to these components, the coating material may contain, for example, a conductive material for increasing the conductivity of the active material. As the solvent, for example, N-methyl-2-pyrrolidone, N, N-dimethylformamide and the like can be used.

  The mixing method of the components constituting the paint such as the active material, the binder, the solvent, and the conductive material is not particularly limited, and the mixing order is not particularly limited. For example, first, an active material, a conductive material, and a binder are mixed, and N-methyl-2-pyrrolidone is added to and mixed with the obtained mixture to prepare a coating material.

  The paint is applied to the current collectors 12 and 22. There is no restriction | limiting in particular as an application | coating method, The method employ | adopted when producing an electrode normally can be used. Examples thereof include a slit die coating method and a doctor blade method.

(Solvent removal step)
Subsequently, the solvent in the paint applied on the current collectors 12 and 22 is removed. The removal method is not particularly limited, and the current collectors 12 and 22 to which the paint is applied may be dried, for example, in an atmosphere of 80 ° C. to 150 ° C.

  Then, the electrodes on which the active material layers 14 and 24 are formed in this way may then be pressed by a roll press device or the like as necessary. The linear pressure of the roll press can be, for example, 10 to 50 kgf / cm.

  Through the above steps, the electrode active material layers 14 and 24 are formed on the current collectors 12 and 22, and the phosphate-derived structure represented by the above formula (I) is formed on the surfaces of the electrode active material layers 14 and 24. An electrode before the polymer having the unit is formed (hereinafter referred to as “electrode before polymer formation”) can be produced.

(Polymer formation process)
Subsequently, the positive electrode and the negative electrode before polymer formation are laminated via the separator 18. For example, by immersing this laminate in the non-aqueous electrolyte solution of the present invention, connecting the leads 60 and 62 to a charge / discharge tester and charging / discharging at least once, the positive electrode active material layer before polymer formation, and A polymer having a phosphate-derived structural unit represented by the above formula (I) can be formed on the negative electrode active material layer before polymer formation, and the positive electrode 10 and the negative electrode 20 can be produced. The existence state of the polymer is not necessarily clear, but it is attached to the surface of the active material or the binder or bonded to the active material or the binder to cover the surfaces of the electrode active material layers 14 and 24. Inferred.

The polymer can be prepared under the conditions set during the charge / discharge test using a charge / discharge tester used in a normal charge / discharge test, and is not particularly limited as long as it is a normal charge / discharge condition. For example, at a voltage of 3.0 to 4.3 V, a current density of 0.001 to 10 mA / cm ² and a temperature of 20 to 30 ° C., the battery may be charged to about 80 to 100% at full charge and discharged to 3.0 V. .

  In the polymer forming step, the positive electrode or the negative electrode and the lithium metal sheet are laminated via a separator, a half cell laminate is prepared for each of the positive electrode and the negative electrode, and the half cell laminate according to the present invention. Phosphoric acid represented by the above formula (I) on the surface of the positive electrode active material layer and the surface of the negative electrode active material layer by immersing in an electrolytic solution and charging and discharging at least once under the above charge and discharge conditions. A polymer having a salt-derived structural unit may be formed, and the positive electrode 10 and the negative electrode 20 may be produced separately.

  Here, another component of the lithium ion secondary battery 100 using the electrode manufactured as described above will be described.

  The separator 18 is an electrically insulating porous body, for example, a single layer of a film made of polyethylene, polypropylene or polyolefin, a stretched film of a laminate or a mixture of the above resins, or a group consisting of cellulose, polyester and polypropylene. Examples thereof include a nonwoven fabric made of at least one selected constituent material.

  The case 50 seals the laminated body 30 and the electrolytic solution therein. The case 50 is not particularly limited as long as it can prevent leakage of the electrolytic solution to the outside and entry of moisture and the like into the electrochemical device 100 from the outside. For example, as the case 50, as shown in FIG. 1, a metal laminate film in which a metal foil 52 is coated with a polymer film 54 from both sides can be used. For example, an aluminum foil can be used as the metal foil 52 and a film such as polypropylene can be used as the polymer film 54. For example, the material of the outer polymer film 54 is preferably a polymer having a high melting point such as polyethylene terephthalate (PET) or polyamide, and the material of the inner polymer film 54 is polyethylene (PE) or polypropylene (PP). preferable.

  The leads 60 and 62 are made of a conductive material such as aluminum.

  Then, the leads 60 and 62 are welded to the positive electrode current collector 12 and the negative electrode current collector 22 by a known method, respectively, and a separator is provided between the positive electrode active material layer 14 of the positive electrode 10 and the negative electrode active material layer 24 of the negative electrode 20. 18 may be inserted into the case 50 together with the electrolytic solution with the 18 interposed therebetween, and the entrance of the case 50 may be sealed.

  As mentioned above, although non-aqueous electrolyte of this invention, an electrode, a lithium ion secondary battery provided with the said electrolyte and electrode, and suitable one Embodiment of those manufacturing methods were demonstrated in detail, this invention is the above-mentioned. It is not limited to the embodiment.

  For example, the electrolytic solution and electrode of the present invention can be used for electrochemical devices other than lithium ion secondary batteries. Electrochemical devices include secondary batteries other than lithium ion secondary batteries such as metallic lithium secondary batteries (using the above active material as the cathode and metallic lithium as the anode), and electrochemical capacitors such as lithium capacitors. Etc. These electrochemical elements can be used for power sources such as self-propelled micromachines and IC cards, and distributed power sources arranged on or in a printed circuit board. In the case of an electrochemical device other than a lithium ion secondary battery, a material suitable for each electrochemical device may be used as the electrode active material. For example, in the case of an electrochemical capacitor, acetylene black, graphite, graphite, activated carbon, or the like is used as the active material contained in the positive electrode active material-containing layer and the negative electrode active material-containing layer.

[Function and effect]
The reason why the effect of the present invention is obtained is not necessarily clear, but the present inventors infer the reason why the above effect is obtained as follows. When the electrochemical device is charged and discharged for the first time, the surface of the electrode active material layer in contact with the electrolytic solution, for example, the surface of the active material or the surface of the binder has a structural unit derived from the phosphate represented by the above formula (I) A polymer is formed. Since the phosphate represented by the above formula (I) has at least two (meth) acryloyloxyalkyl groups in one molecule, it is derived from the phosphate represented by the above formula (I). It is thought that a network polymer having a structural unit can be formed. The polymer is considered to be excellent in stability, for example, it can effectively suppress the reaction between the electrolyte and the electrode active material, and can reduce the amount of heat generated in the electrode active material layer during abnormal heat generation. It is done. In addition, when the phosphate represented by the formula (III) is present, the phosphate represented by the formula (III) can also be polymerized, and therefore the polymer is represented by the formula (III). A phosphate-derived structural unit. The polymer structure is presumed to be a polymer in which vinyl groups in a (meth) acryloyloxy group are polymerized, or a polymer in which the polymers are further polymerized by dehydration condensation of a hydroxyl group contained in the polymer.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
[Creation of negative electrode]
Artificial graphite as a negative electrode active material, styrene-butadiene rubber as a binder, carboxymethyl cellulose as a thickener, and water as a solvent were mixed to prepare a paint. This paint was applied to a copper foil (thickness: 15 μm) as a current collector by a doctor blade method, dried at 80 ° C., and then rolled to form a positive electrode active material layer on the surface of the copper foil. The copper foil was provided with a portion to which no paint was applied in order to connect the external lead terminal. As the external lead terminal, a nickel foil wound with polypropylene grafted with maleic anhydride was prepared for the purpose of improving the sealing performance with the exterior body. The nickel foil and the copper foil after the coating material was applied and dried were ultrasonically welded.

[Creation of positive electrode]
Li (Ni _0.82 Co _0.15 Al _0.03 ) O ₂ as a positive electrode active material, polyvinylidene fluoride as a binder, carbon black and graphite as a conductive additive, N-methylpyrrolidone as a solvent, and a paint Created. This paint was applied to an aluminum foil (thickness 20 μm) as a current collector by a doctor blade method, dried at 100 ° C., and then rolled to form a positive electrode active material layer on the surface of the aluminum foil. The aluminum foil was provided with a portion to which no paint was applied in order to connect the external lead terminal. As an external lead terminal, for the purpose of improving the sealing property with the exterior body, an aluminum foil wrapped with polypropylene grafted with maleic anhydride was prepared. This aluminum foil and the aluminum foil after the coating material was applied and dried were ultrasonically welded.

[Creation of electrolyte]
LiPF ₆ was dissolved at a concentration of 1 M in a solution obtained by mixing ethylene carbonate at a ratio of 30 vol% and diethyl carbonate at a ratio of 70 vol% to prepare an electrolytic solution. In this electrolyte solution, hydrogen phosphate = bis [2- (methacryloyloxy) ethyl] ((CH ₂ CCH ₃ COO— (CH ₂ ) ₂ —O—) ₂ —POOH, phosphate (a) in Table 1 and And 2- (methacryloyloxy) ethyl phosphate (CH ₂ CCH ₃ COO— (CH ₂ ) ₂ —O—PO (OH) ₂ , represented by phosphate (b) in Table 1), 0.1 mass% of phosphate (manufactured by Kyoeisha Chemical Co., Ltd., (trade name) P-2M) containing 80:20 in a ratio was added and dissolved.

[Create half-cell]
(Preparation of positive electrode half cell)
The positive electrode prepared as described above and a separator (polyolefin microporous membrane, manufactured by Asahi Kasei Corporation, (trade name) SV722) were cut into predetermined dimensions. A positive electrode, a separator, and a lithium metal were laminated in this order to produce a positive electrode half-cell laminate. The outer package of the battery enclosing the laminate was made of an aluminum laminate material, and the configuration thereof was polyethylene terephthalate (12 μm) / Al (40 μm) / polypropylene (50 μm). At this time, bags were made so that PP was inside. The laminate was placed in the outer package, an appropriate amount of the electrolyte prepared as described above was added, and the outer package was vacuum-sealed to produce a positive electrode half cell.

(Preparation of negative electrode half cell)
A negative electrode half cell was produced in the same manner as the production method of the positive electrode half cell except that the negative electrode, the separator, and the lithium metal were laminated in this order to produce a laminate for the negative electrode half cell.

<Measurement of discharge capacity>
When the positive electrode half cell and the negative electrode half cell prepared as described above were subjected to a charge / discharge tester (manufactured by Hokuto Denko Corporation, (product name) HJ1001SM8A) with a discharge rate of 0.1 C (constant current discharge at 25 ° C.) The discharge capacity (unit: mAh / g) was measured when the current value reached the end of discharge in 10 hours. Table 1 shows the discharge capacity of the positive electrode and the discharge capacity of the negative electrode.
In addition, from the electrolyte solution collected from the battery after charge and discharge, CH ₂ CCH ₃ COO— (CH ₂ ) ₂ —O—PO (OH) — (CH ₂ ) ₂ —OCO—OC ₂ H ₅ , CH ₂ CCH _{3 COO- (CH 2) 2 -O} -PO (OH) -CH 2 -O-PO (OH) -O- (CH 2) -O-COCCH 3 CH 2, (CH 2 CCH 3 COO- (CH 2 ) ₂ -O-) ₂ -POO- (CH ₂ ) ₂ -OPOF-OC ₂ H _{5 and the} like were detected in minute amounts. This is a substance produced by decomposition of a part of the additive and reaction with a part of the solvent or the supporting salt, and the performance of the battery was not impaired.

<Measurement of calorific value of positive electrode active material layer>
After the charge / discharge test, the positive electrode half cell was disassembled, a part of the positive electrode active material layer was taken out, about 1 mg was placed in a 5 mm diameter SUS pan and sealed with a SUS lid, and then a differential scanning calorimeter (manufactured by Rigaku Corporation, (Product name: Thermo plus DSC8230), the calorific value was measured. The measurement range was 25 ° C. to 500 ° C., the rate of increase was 10 ° C./min, and the reference material was alumina (attached to a differential scanning calorimeter). The exotherm began at about 230 ° C.

(Example 2)
The positive electrode half cell and the negative electrode half cell were the same as in Example 1 except that the phosphate content in the electrolytic solution was 1.0 mass% (the content of phosphate (a): 0.8 mass%). Was made.

(Example 3)
A positive electrode half cell and a negative electrode half cell in the same manner as in Example 1 except that the phosphate content in the electrolytic solution was changed to 3.0% by mass (the content of phosphate (a): 2.4% by mass). Was made.

Example 4
A positive electrode half cell and a negative electrode half cell in the same manner as in Example 1 except that the phosphate content in the electrolytic solution was 3.5% by mass (the content of phosphate (a): 2.8% by mass). Was made.

(Example 5)
The positive electrode half cell and the negative electrode half cell were the same as in Example 1 except that the phosphate content in the electrolyte was 0.005 mass% (the content of phosphate (a): 0.004 mass%). Was made.

(Example 6)
The positive electrode half cell and the negative electrode half cell were the same as in Example 1 except that the phosphate content in the electrolyte was 0.01% by mass (the content of phosphate (a): 0.008% by mass). Was made.

(Comparative Example 1)
A positive electrode half cell and a negative electrode half cell were produced in the same manner as in Example 1 except that no additive was used in the electrolytic solution.

(Comparative Example 2)
A positive electrode half cell and a negative electrode half cell were produced in the same manner as in Example 1 except that 1.0% by mass of methyl methacrylate was added instead of 0.1% by mass of the phosphate.

(Comparative Example 3)
A positive electrode half cell and a negative electrode half cell were produced in the same manner as in Example 1 except that 1.0% by mass of ethyl methacrylate was added instead of 0.1% by mass of phosphate.

(Comparative Example 4)
A positive electrode half cell and a negative electrode half cell were prepared in the same manner as in Example 1 except that methyl methacrylate was added instead of phosphate.

(Comparative Example 5)
A positive electrode half cell and a negative electrode half cell were prepared in the same manner as in Example 1 except that ethyl methacrylate was added instead of phosphate.

(Comparative Example 6)
A positive electrode half cell and a negative electrode half cell were prepared in the same manner as in Example 1 except that vinylene carbonate (VC) and propane sultone (PS) were added in a total amount of 1.0% by mass instead of 0.1% by mass phosphate. Produced.

  In Examples 2 to 6 and Comparative Examples 1 to 6, as in Example 1, the discharge capacities of the positive electrode and the negative electrode were measured for the positive electrode half cell and the negative electrode half cell. Further, as in Example 1, the calorific value of the positive electrode active material layer was measured. Table 1 shows the discharge capacity of the positive electrode, the discharge capacity of the negative electrode, and the calorific value of the positive electrode active material layer in Examples 1 to 6 and Comparative Examples 1 to 6.

In the examples, phosphoric acid containing hydrogen phosphate = bis [2- (methacryloyloxy) ethyl] ((CH ₂ CCH ₃ COO— (CH ₂ ) ₂ —O—) ₂ —POOH: phosphate (a)) Even when the acid salt was less than 1.0% by mass, the effect of reducing the heat generation amount was sufficiently obtained. On the other hand, as shown in the comparative example, the electrolyte solution to which methyl methacrylate, ethyl methacrylate, or a mixture of VC and PS was added had a low heating value reduction effect unless 1.0% by mass or more was added.

  DESCRIPTION OF SYMBOLS 10,20 ... Electrode, 12 ... Positive electrode collector, 14 ... Positive electrode active material layer, 18 ... Separator, 22 ... Negative electrode collector, 24 ... Negative electrode active material layer, 30 ... Laminate, 50 ... Case, 52 ... Metal Foil, 54 ... polymer film, 60, 62 ... lead, 100 ... lithium ion secondary battery.

Claims (8)

A non-aqueous solvent containing a compound represented by formula (I) in which two or more hydrogen atoms among three hydrogen atoms of phosphoric acid are substituted with a (meth) acryloyloxyalkyl group, a nonaqueous solvent, and an electrolyte Aqueous electrolyte.

[In Formula (I), X ¹ and X ² represent a hydrogen atom or a methyl group, X ¹ and X ² may be the same or different, and R ¹ is a hydrogen atom or a hydrocarbon having 1 to 24 carbon atoms. A group or a (meth) acryloyloxyalkyl group represented by the formula (II), a and b each represent an integer of 1 to 10, and a and b may be the same or different. ]

[In Formula (II), X ³ represents a hydrogen atom or a methyl group, and c represents an integer of 1 to 10. ] The non-aqueous electrolyte solution according to claim 1, further comprising a compound represented by formula (III).

[In Formula (III), X ⁴ represents a hydrogen atom or a methyl group, and d represents an integer of 1 to 10. ]   The non-aqueous electrolyte solution according to claim 1 or 2, wherein the content of the compound represented by the formula (I) is 0.0008% by mass to 4.0% by mass.   The non-aqueous electrolyte solution according to claim 1 or 2, wherein the content of the compound represented by the formula (I) is 0.008% by mass to 3.0% by mass. A current collector,
An active material layer comprising an active material, a binder, and a polymer having a structural unit derived from the compound represented by formula (I), and formed on the surface of the current collector;
Electrode.

[In Formula (I), X ¹ and X ² represent a hydrogen atom or a methyl group, X ¹ and X ² may be the same or different, and R ¹ is a hydrogen atom or a hydrocarbon having 1 to 24 carbon atoms. A group or a (meth) acryloyloxyalkyl group represented by the formula (II), a and b each represent an integer of 1 to 10, and a and b may be the same or different. ]

[In Formula (II), X ³ represents a hydrogen atom or a methyl group, and c represents an integer of 1 to 10. ] The electrode according to claim 5, wherein the polymer further has a structural unit derived from the compound represented by the formula (III).

[In Formula (III), X ⁴ represents a hydrogen atom or a methyl group, and d represents an integer of 1 to 10. ]   An electrochemical device comprising the nonaqueous electrolytic solution according to any one of claims 1 to 4.   An electrochemical device comprising the electrode according to claim 5.

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