WO2015037379A1

WO2015037379A1 - Novel compound, electrolyte, and secondary battery

Info

Publication number: WO2015037379A1
Application number: PCT/JP2014/071278
Authority: WO
Inventors: 登吉田; 伊紀子島貫; 川崎　大輔; 石川　仁志
Original assignee: 日本電気株式会社
Priority date: 2013-09-13
Filing date: 2014-08-12
Publication date: 2015-03-19
Also published as: JPWO2015037379A1

Abstract

The objective of the present invention is to provide a novel compound which can improve the performance of a secondary battery. By including a compound represented by formula (1) in an electrolyte, capacity retention can be improved and volume increase rate can be suppressed in a secondary battery. (In the formula, R₁ is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, which may be branched, and R₂ is a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, which is a single bond or may be branched.)

Description

New compounds, electrolytes and secondary batteries

This embodiment relates to a novel compound. In addition, this embodiment preferably relates to an electrolytic solution containing the novel compound. In addition, the present embodiment preferably relates to a secondary battery including the electrolytic solution.

With the rapid market expansion of notebook computers, mobile phones, electric vehicles, etc., secondary batteries with excellent performance are required, and electrolytes containing various additives to improve the performance of secondary batteries Has been developed.

For example, Patent Document 1 discloses an electrolyte solution for a secondary battery containing an aprotic solvent and a cyclic sulfonate ester having at least two sulfonyl groups.

Patent Document 2 discloses a nonaqueous electrolyte composition containing a supporting salt, a nonaqueous solvent, a phosphoric ester acid, and a compound having a sulfone structure.

Patent Document 3 discloses an electrolytic solution containing a solvent, a supporting salt, and at least one of sulfone compounds represented by a predetermined formula.

Patent Document 4 includes a solvent and a supporting salt, and the solvent includes an ester compound represented by a predetermined formula, lithium monofluorophosphate (Li ₂ PFO ₃ ), and lithium difluorophosphate (LiPF ₂ O ₂ ). An electrolyte containing at least one of the above and at least one of the anhydrous compounds represented by the predetermined formula is disclosed.

Patent Document 5 discloses an electrolytic solution containing a non-aqueous solvent containing a sulfonic acid and a carboxylic acid anhydride represented by a predetermined formula, and a supporting salt.

JP 2004-281368 A JP 2008-041635 A JP 2010-034087 A JP 2010-165542 A Japanese Patent Laid-Open No. 2002-008718

As disclosed in Patent Documents 1 to 6, electrolytic solutions containing various additives are disclosed for the purpose of improving the performance of secondary batteries.

The present invention aims to provide a novel compound capable of improving the performance of a secondary battery.

Embodiment of this invention is a compound represented by following formula (1).

(In Formula (1), R ₁ represents a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms which may be branched. R ₂ represents a single bond or a substituted or unsubstituted group which may be branched. And represents a substituted alkylene group having 1 to 5 carbon atoms.).

Further, an embodiment of the present invention is an electrolytic solution containing the compound.

Moreover, embodiment of this invention is a secondary battery containing the said electrolyte solution.
In addition, an embodiment of the present invention is an electrolytic solution including a nonaqueous solvent and a cyclic organic compound having at least two groups represented by the following formula (301).

According to the present invention, a novel compound capable of improving the performance of a secondary battery can be provided.

It is typical sectional drawing which shows the structure of the electrode laminated body which a laminated laminate type secondary battery has.

Hereinafter, embodiments of the present invention will be described in detail.

In the formula (1), the substituent of R ₁ is, for example, an optionally branched alkyl group, an optionally branched halogen-substituted alkyl group, an optionally branched alkenyl group, or an optionally branched group. An alkynyl group, an optionally branched alkoxy group, an amino group, a hydroxy group, or a halogen atom. When there are a plurality of substituents for R ₁ , they may be independent from each other.

The substituent of R ₁ may be branched, an alkyl group having 1, 2, 3 or 4 carbon atoms (eg, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group), or a branched group. A halogen-substituted alkyl group having 1, 2, 3 or 4 carbon atoms (for example, a perfluoromethyl group or a perfluoroethyl group), an optionally branched alkenyl group having 2, 3, or 4 carbon atoms (for example, a vinyl group, 1-propenyl group, 2-propenyl group, 2-butenyl group), an alkynyl group having 2, 3 or 4 carbon atoms which may be branched (for example, acetylenyl group, 1-propynyl group, 2-propynyl group, 2- Butynyl group), an optionally branched alkoxy group having 1, 2, 3 or 4 carbon atoms (for example, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butyl group) A hydroxyl group, a hydroxyl group, or a halogen atom (for example, a fluorine atom, a chlorine atom, or a bromine atom).
The substituent of R ₁ is an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched fluorine substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom. It is more preferable that

In the formula (1), the substituent of R ₂ may be, for example, an optionally branched alkyl group, an optionally branched halogen-substituted alkyl group, an optionally branched alkenyl group, or an optionally branched group. An alkynyl group, an optionally branched alkoxy group, an amino group, a hydroxy group, or a halogen atom. When there are a plurality of substituents for R ₂ , they may be independent from each other.

The substituent of R ₂ may be branched, an alkyl group having 1, 2, 3 or 4 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group), or a branched group. A halogen-substituted alkyl group having 1, 2, 3 or 4 carbon atoms (for example, a perfluoromethyl group or a perfluoroethyl group), an optionally branched alkenyl group having 2, 3, or 4 carbon atoms (for example, a vinyl group, 1-propenyl group, 2-propenyl group, 2-butenyl group), an alkynyl group having 2, 3 or 4 carbon atoms which may be branched (for example, acetylenyl group, 1-propynyl group, 2-propynyl group, 2- Butynyl group), an optionally branched alkoxy group having 1, 2, 3 or 4 carbon atoms (for example, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butyl group) A hydroxyl group, a hydroxyl group, or a halogen atom (for example, a fluorine atom, a chlorine atom, or a bromine atom).
The substituent of R ₂ is an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched fluorine substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom. It is more preferable that

The halogen-substituted alkyl group represents a substituted alkyl group having a structure in which at least one hydrogen atom in the unsubstituted alkyl group is substituted with a halogen atom (for example, a fluorine atom, a chlorine atom, or a bromine atom). The halogen-substituted alkyl group is preferably a fluorine-substituted alkyl group. The fluorine-substituted alkyl group represents a substituted alkyl group having a structure in which at least one hydrogen atom in the unsubstituted alkyl group is substituted with a fluorine atom.

In the formula (1), the carbon number of R ₁ is preferably 1 to 4, more preferably 1 to 3, and further preferably 1 to 2.

In the formula (1), the carbon number of R ₂ is preferably 0 to 4, more preferably 0 to 3, and further preferably 0 to 2. Incidentally, when the number of carbon atoms of R ₂ is 0, a case R ₂ is a single bond. When R ₂ is a single bond, a case where carbon atoms adjacent to R ₂ in the formula (1) are bonded to each other is shown.

The compound of the present embodiment is preferably represented by the following formula (2).

(In the formula (2), m is an integer of 1, 2, 3, or 4. n is an integer of 0, 1, 2, 3, or 4. R ₁₁ and R ₁₂ are each independently A hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched fluorine substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom. ₁₁ and R ₁₂ are each independent for each carbon atom to which they are bonded, and R ₁₃ and R ₁₄ are each independently a hydrogen atom or an optionally branched alkyl having 1, 2, 3 or 4 carbon atoms. A group, an optionally branched fluorine-substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom, each of R ₁₃ and R ₁₄ is independent for each bonded carbon atom. .

The compound of the present embodiment is more preferably represented by the following formula (3) or (4).

(In Formula (3), R ₁₀₁ and R ₁₀₂ are each independently a hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched carbon number 1, 2, 3 or 4 fluorine-substituted alkyl groups, or fluorine atoms).

(In Formula (4), R ₂₀₁ and R ₂₀₂ are each independently a hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched carbon number 1, A fluorine-substituted alkyl group having 2, 3 or 4 or a fluorine atom, and R ₂₀₃ and R ₂₀₄ are each independently a hydrogen atom or an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms. is there.).

Specific examples of the compound of the present embodiment are listed below.

The compound of the present embodiment can be used as an additive contained in the electrolyte solution of the secondary battery. By adding the compound of the present embodiment to the electrolytic solution, the capacity retention rate of the secondary battery can be improved and gas generation can be suppressed.

Hereinafter, the electrolytic solution and the secondary battery of this embodiment will be described.

[1] Electrolytic Solution The electrolytic solution in the present embodiment includes the compound of the present embodiment represented by the formula (1).

The compound of the present embodiment forms a SEI (Solid Electrolyte Interface) film on the electrode surface, and as a result, can suppress decomposition of the solvent in the electrolytic solution. That is, the compound of this embodiment undergoes reductive decomposition at the negative electrode to form a film on the negative electrode. Since this film has a carbonyl group and a sulfonyl group and is excellent in ionic conductivity, it can suppress decomposition of the solvent in the electrolytic solution, and as a result, it can suppress a decrease in capacity maintenance rate and gas generation. It is considered a thing. The above mechanism and theory are speculations and do not limit the present invention.

The content of the compound of the present embodiment in the electrolytic solution is not particularly limited, but is preferably 0.1 to 10% by mass, more preferably 0.3 to 8.0% by mass. Preferably, the content is 1.0 to 5.0% by mass. When content of the compound of this embodiment is 0.1 mass% or more, a film | membrane can be effectively formed in an electrode and the decomposition | disassembly of a nonaqueous solvent can be suppressed effectively as a result. Moreover, when content of the compound of this embodiment is 10 mass% or less, the raise of the internal resistance of a battery by the excessive growth of a SEI film | membrane can be suppressed effectively.

The electrolytic solution contains, for example, a supporting salt and a nonaqueous solvent in addition to the compound of the present embodiment.

As the supporting salt, and it is not particularly present invention is limited, for _{_{_{example, LiPF 6, LiAsF 6, LiAlCl}}} 4, LiClO 4, LiBF 4, LiSbF 6, LiCF 3 SO 3, LiC 4 F 9 SO 3, Li Examples thereof include lithium salts such as (CF ₃ SO ₂ ) ₂ and LiN (CF ₃ SO ₂ ) ₂ . The supporting salt can be used alone or in combination of two or more.

The concentration of the supporting salt in the electrolytic solution is preferably 0.5 to 1.5 mol / l. By setting the concentration of the supporting salt within this range, it becomes easy to adjust the density, viscosity, electrical conductivity, and the like to an appropriate range.

As the non-aqueous solvent, the present invention is not particularly limited. For example, carbonates such as cyclic carbonates and chain carbonates, aliphatic carboxylic acid esters, γ-lactones, cyclic ethers, chain And ethers thereof, fluorine derivatives thereof and the like. These can be used individually by 1 type or in combination of 2 or more types.

Examples of cyclic carbonates include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC).

Examples of chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and dipropyl carbonate (DPC).

Examples of the aliphatic carboxylic acid esters include methyl formate, methyl acetate, and ethyl propionate.

Examples of γ-lactones include γ-butyrolactone.

Examples of cyclic ethers include tetrahydrofuran and 2-methyltetrahydrofuran.

Examples of chain ethers include 1,2-diethoxyethane (DEE), ethoxymethoxyethane (EME), and the like.

Other non-aqueous solvents include, for example, dimethyl sulfoxide, 1,3-dioxolane, formamide, acetamide, dimethylformamide, acetonitrile, propylnitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivatives , Sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, N-methylpyrrolidone, fluorinated carboxylic acid ester, methyl-2 , 2,2-trifluoroethyl carbonate, methyl-2,2,3,3,3-pentafluoropropyl carbonate, trifluoromethyl ethylene carbonate, monofluoromethyl ethyl Emissions carbonate, difluoromethyl ethylene carbonate, 4,5-difluoro-1,3-dioxolan-2-one, mono-fluoroethylene carbonate, and the like. These can be used individually by 1 type or in combination of 2 or more types.

The non-aqueous solvent preferably contains carbonates. The carbonates include cyclic carbonates or chain carbonates. Since carbonates have a large relative dielectric constant, the ion dissociation property of the electrolytic solution is improved, and further, the viscosity of the electrolytic solution is lowered, so that the ion mobility is improved. However, when carbonates having a carbonate structure are used as the non-aqueous solvent for the electrolytic solution, the carbonates tend to decompose and generate gas containing CO ₂ . In particular, in the case of a laminated laminate type secondary battery, when gas is generated inside the battery, the problem of blistering appears prominently and tends to lead to performance degradation. Therefore, in this embodiment, by adding the compound of this embodiment to a non-aqueous solvent containing carbonates, the SEI film formed by the compound of this embodiment suppresses the decomposition of carbonates, Occurrence can be suppressed. Therefore, in this embodiment, it is preferable that electrolyte solution contains carbonates as a nonaqueous solvent in addition to the compound of this embodiment. With such a configuration, even when carbonates are used as a non-aqueous solvent, gas generation can be reduced, and a secondary battery having high performance can be provided. The content of carbonates in the electrolytic solution is, for example, 30% by mass or more, preferably 50% by mass or more, and more preferably 70% by mass or more.

The LUMO value of the compound of the present embodiment is preferably smaller than the LUMO value of the solvent used in the electrolytic solution. Common solvents include EC (1.18 eV), DEC (1.26 eV), PC (1.24 eV), and the like. The LUMO value of the compound of this embodiment is preferably 0 or less, more preferably −0.5 or less. Thereby, the compound of this embodiment can be reduced and decomposed before the solvent in the electrolytic solution to form a film on the negative electrode, and the decomposition of the solvent can be suppressed. The LUMO value can be calculated, for example, by molecular orbital calculation using MOPAC (Molecular Orbital PACage).

The LUMO values (eV) of the compounds (101 to 115) are shown in Table 1.

In addition, the electrolytic solution of the present embodiment includes a non-aqueous solvent and a cyclic organic compound having at least two groups represented by the following formula (301).

The cyclic organic compound having at least two groups represented by the formula (301) can be reductively decomposed on the negative electrode to form a film having excellent ionic conductivity.

[2] Negative Electrode The secondary battery of the present embodiment includes a negative electrode having a negative electrode active material. The negative electrode active material can be bound on the negative electrode current collector by a negative electrode binder.

As the negative electrode active material, the present invention is not particularly limited. For example, lithium metal, metal (a) capable of being alloyed with lithium, metal oxide (b) capable of inserting and extracting lithium ions, or lithium Examples thereof include a carbon material (c) that can occlude and release ions. A negative electrode active material can be used individually by 1 type or in combination of 2 or more types.

Examples of the metal (a) include Al, Si, Pb, Sn, In, Bi, Ag, Ba, Ca, Hg, Pd, Pt, Te, Zn, La, or alloys of two or more thereof. It is done. Moreover, you may use these metals or alloys in mixture of 2 or more types. These metals or alloys may contain one or more non-metallic elements. Among these, it is preferable to use silicon, tin, or an alloy thereof as the negative electrode active material. By using silicon or tin as the negative electrode active material, a lithium secondary battery excellent in weight energy density and volume energy density can be provided.

Examples of the metal oxide (b) include silicon oxide, aluminum oxide, tin oxide, indium oxide, zinc oxide, lithium oxide, and composites thereof. Among these, it is preferable to use silicon oxide as the negative electrode active material. Further, the metal oxide (b) can contain, for example, 0.1 to 5% by mass of one or more elements selected from nitrogen, boron and sulfur.

Examples of the carbon material (c) include graphite, amorphous carbon, diamond-like carbon, carbon nanotube, or a composite thereof.

As the negative electrode binder, the present invention is not particularly limited, and examples thereof include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene. Examples include copolymer rubber, polytetrafluoroethylene, polypropylene, polyethylene, polyimide, polyamideimide, and polyacrylic acid. Of these, polyvinylidene fluoride or styrene-butadiene copolymer rubber is preferred because of its high binding properties. The amount of the negative electrode binder is preferably 0.5 to 25 parts by mass and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the negative electrode active material. Moreover, carboxymethylcellulose can be added as a thickener.

As the negative electrode current collector, aluminum, nickel, stainless steel, chromium, copper, silver, and alloys thereof are preferable in view of electrochemical stability. Examples of the shape include a foil, a flat plate, and a mesh.

The negative electrode can be produced by forming a negative electrode active material layer containing a negative electrode active material and a negative electrode binder on a negative electrode current collector. Examples of the method for forming the negative electrode active material layer include a doctor blade method, a die coater method, a CVD method, and a sputtering method. After forming a negative electrode active material layer in advance, a thin film of aluminum, nickel, or an alloy thereof may be formed on the negative electrode active material layer by a method such as vapor deposition or sputtering to produce a negative electrode.

[3] Positive Electrode The secondary battery of this embodiment includes a positive electrode having a positive electrode active material. The positive electrode active material can be bound on the positive electrode current collector by a positive electrode binder.

The positive electrode active material is not particularly limited, and examples thereof include lithium composite oxide and lithium iron phosphate. Further, at least part of the transition metal of these lithium composite oxides may be replaced with another element. Alternatively, a lithium composite oxide having a plateau at 4.2 V or more at the metal lithium counter electrode potential can be used. Examples of the lithium composite oxide include spinel type lithium manganese composite oxide, olivine type lithium containing composite oxide, and reverse spinel type lithium containing composite oxide.

Examples of the lithium composite oxide include lithium manganate having a layered structure such as LiMnO ₂ and Li _x Mn ₂ O ₄ (0 <x <2), lithium manganate having a spinel structure, or lithium manganate A part of Mn is replaced with at least one element selected from the group consisting of Li, Mg, Al, Co, B, Ti and Zn; lithium cobaltate such as LiCoO ₂ or part of Co of lithium cobaltate Is replaced with at least one element selected from the group consisting of Ni, Al, Mn, Mg, Zr, Ti, and Zn; lithium nickelate such as LiNiO ₂ or a part of Ni in lithium nickelate is Co, Al Replaced with at least one element selected from the group consisting of Mn, Mg, Zr, Ti, Zn; LiN i _1/3 Co _1/3 Mn _1/3 O ₂ or other specific transition metals such as lithium transition metal oxides, or some of the transition metals of the lithium transition metal oxides may be Co, Al, Mn And those substituted with at least one element selected from the group consisting of Mg, Zr; and those lithium transition metal oxides in which Li is excessive in comparison with the stoichiometric composition. In particular, as the lithium composite oxide, Li _α Ni _β Co _γ Al _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.7, γ ≦ 0.2), or Li _α Ni _β Co _γ Mn _δ O ₂ (1 ≦ α ≦ 1.2, β + γ + δ = 1, β ≧ 0.4, γ ≦ 0.4), or a part of transition metals of these composite oxides may be Al, Mg, Zr. Those substituted with at least one element selected from the group consisting of: These lithium composite oxides may be used alone or in combination of two or more.

As the positive electrode active material, an active material that operates at a potential of 4.5 V or higher with respect to lithium (hereinafter also referred to as a 5 V class active material) can be used from the viewpoint that a high voltage can be obtained. When a 5V class active material is used, gas generation due to decomposition of the electrolytic solution or the like is likely to occur, but gas generation can be suppressed by using the electrolytic solution containing the compound of the present embodiment.

As the 5V class active material, for example, a lithium manganese composite oxide represented by the following formula (A) can be used.

Li _a (M _x Mn _2-xy Y _y ) (O _4-w Z _w ) (A)

(In formula (A), 0.4 ≦ x ≦ 1.2, 0 ≦ y, x + y <2, 0 ≦ a ≦ 1.2, and 0 ≦ w ≦ 1. M is Co, Ni, Fe, Cr. And Y is at least one selected from the group consisting of Li, B, Na, Mg, Al, Ti, Si, K and Ca, and Z is F and Cl. At least one selected from the group consisting of:

Also, as the 5V class active material, a spinel compound represented by the following formula (B) is preferably used among such metal complex oxides from the viewpoint of obtaining a sufficient capacity and extending the life.

LiNi _x Mn _2-xy A _y O ₄ (B)

(In the formula (B), 0.4 <x <0.6, 0 ≦ y <0.3, A is at least one selected from the group consisting of Li, B, Na, Mg, Al, Ti and Si. is there.).

In the formula (B), it is more preferable that 0 ≦ y <0.2.

As an active material that operates at a potential of 4.5 V or higher with respect to lithium, an olivine-type positive electrode active material can be given. Examples of the olivine-type 5V active material include LiCoPO ₄ and LiNiPO ₄ .

In addition, as an active material that operates at a potential of 4.5 V or more with respect to lithium, Si composite oxide can be given. As such Si complex oxide, the compound shown by a following formula (C) is mentioned, for example.

Li ₂ MSiO ₄ (C)

(In formula (C), M is at least one selected from the group consisting of Mn, Fe and Co).

Further, the active material that operates at a potential of 4.5 V or more with respect to lithium may have a layered structure. As a 5V class active material containing a layered structure, the compound shown by following formula (D) is mentioned, for example.

_{_{_{Li (M1 x M2 y Mn 2}}} -x-y) O 2 (D)

(In Formula (D), M1 is at least one selected from the group consisting of Ni, Co, and Fe. M2 is at least one selected from the group consisting of Li, Mg, and Al. 0.1 <x <0.5, 0.05 <y <0.3).

As the 5V class active material, lithium metal composite oxides represented by the following (E) to (G) can be used.

LiMPO ₄ (E)

(In formula (E), M is at least one selected from the group consisting of Co and Ni).

Li (M _y Mn _z ) O ₂ (F)

(In formula (F), 0.1 ≦ y ≦ 0.5, 0.33 ≦ z ≦ 0.7, and M is at least one selected from the group consisting of Li, Co, and Ni.) .

_{_{_{_{Li (Li x M y Mn z}}}} ) O 2 (G)

(In Formula (G), 0.1 ≦ x <0.3, 0.1 ≦ y ≦ 0.4, 0.33 ≦ z ≦ 0.7, and M is composed of Li, Co, and Ni. At least one selected from the group).

As the positive electrode binder, the same materials as those mentioned for the negative electrode binder can be used. Among these, polyvinylidene fluoride is preferable from the viewpoint of versatility and low cost. The amount of the positive electrode binder is preferably 2 to 10 parts by mass with respect to 100 parts by mass of the positive electrode active material.

As the positive electrode current collector, the same materials as those mentioned for the negative electrode current collector can be used.

A conductive auxiliary material may be added to the positive electrode active material layer containing the positive electrode active material for the purpose of reducing impedance. Examples of the conductive auxiliary material include carbonaceous fine particles such as graphite, carbon black, and acetylene black.

[4] Separator The separator is not particularly limited. For example, a porous film such as polypropylene or polyethylene or a nonwoven fabric can be used. Moreover, as a separator, the ceramic coat separator which formed the coating containing a ceramic in the polymer base material used as a separator can also be used. Moreover, what laminated | stacked them can also be used as a separator.

[5] Exterior Body The exterior body is not particularly limited, and for example, a laminate film can be used. For example, in the case of a laminated laminate type secondary battery, a laminated film such as polypropylene or polyethylene coated with aluminum or silica can be used.

In the case of a secondary battery using a laminate film as the exterior body, the distortion of the electrode laminate becomes very large when gas is generated, compared to a secondary battery using a metal can as the exterior body. This is because the laminate film is more easily deformed by the internal pressure of the secondary battery than the metal can. Furthermore, when sealing a secondary battery using a laminate film as an exterior body, the internal pressure of the battery is usually lower than the atmospheric pressure, so there is no extra space inside, and if gas is generated, it is immediately It tends to lead to battery volume change and electrode stack deformation. However, the secondary battery according to the present embodiment can overcome such problems by using the electrolytic solution containing the compound of the present embodiment.

[6] Secondary Battery The structure of the secondary battery according to the present embodiment is not particularly limited by the present invention. For example, an electrode laminate in which a positive electrode and a negative electrode are arranged to face each other and an electrolytic solution are provided. The structure included in the exterior body can be given. The shape of the secondary battery is not particularly limited, and examples thereof include a cylindrical shape, a flat wound rectangular shape, a laminated rectangular shape, a coin shape, a flat wound laminated shape, and a laminated laminated shape.

Hereinafter, a laminated laminate type secondary battery will be described as an example. FIG. 1 is a schematic cross-sectional view showing a structure of an electrode laminate included in a laminate-type secondary battery. The electrode laminate is formed by alternately stacking a plurality of positive electrodes c and a plurality of negative electrodes a with a separator b interposed therebetween. The positive electrode current collector e of each positive electrode c is welded to and electrically connected to each other at an end portion not covered with the positive electrode active material, and a positive electrode terminal f is welded to the welded portion. The negative electrode current collector d of each negative electrode a is welded and electrically connected to each other at an end portion not covered with the negative electrode active material, and a negative electrode terminal g is welded to the welded portion.

Since the electrode laminate having such a planar laminate structure does not have a small R portion (region close to the winding core of the wound structure), the electrode laminate is associated with charge / discharge as compared with the electrode laminate having the wound structure. There is an advantage that it is not easily influenced by the volume change of the electrode. However, in an electrode laminate having a planar laminated structure, when gas is generated between the electrodes, the generated gas tends to stay between the electrodes. This is because, in the case of an electrode laminate having a wound structure, the distance between the electrodes is difficult to spread because tension is applied to the electrodes, whereas in the case of an electrode laminate having a laminated structure, It is because it is easy to spread. In particular, when the exterior body is an aluminum laminate film, this problem appears remarkably. In the secondary battery of this embodiment, such a problem can be solved by using the electrolytic solution containing the compound of this embodiment, and a laminated laminate type lithium ion secondary battery using a high energy type negative electrode. Even a battery can be driven for a long life.

(Example)
Hereinafter, the present embodiment will be specifically described by way of examples.

(Production Example 1)
Compound (101) was produced by the following method.
An acetonitrile solution of methylenedisulfonyl chloride was added dropwise at 40 ° C. or lower to dehydrated acetonitrile to which silver carbonate was added. The solution was then stirred at room temperature for 24 hours before the solution was filtered through celite. Next, the solution that remained on the celite without filtration was washed with acetonitrile. Next, oxalyl dichloride was added to the resulting solution and reacted at room temperature for 24 hours. Next, the obtained solution was filtered through celite, washed with acetonitrile, and concentrated with an evaporator to obtain a target substance.

(Production Examples 2 to 15)
Using the same scheme as in Production Example 1, production was carried out by changing the raw material.
For the fluorine-substituted compounds (compounds 103, 105, 108, 110, 113, 115), after synthesis of unsubstituted compounds, 1,1,2,2, -tetrafluoroethyl-N, N-dimethylamine was used. Synthesized by fluorine substitution.

(analysis)
It was confirmed by NMR that the compounds obtained in Production Examples 1 to 15 were the compounds (101) to (115).

Example 1
<Negative electrode>
Graphite was used as the negative electrode active material. This negative electrode active material, polyvinylidene fluoride as a negative electrode binder, and acetylene black as a conductive auxiliary material were weighed in a mass ratio of 75: 20: 5. These were mixed with N-methylpyrrolidone to prepare a negative electrode slurry. The negative electrode slurry was applied to a copper foil having a thickness of 10 μm, dried, and further subjected to a heat treatment at 120 ° C. in a nitrogen atmosphere to produce a negative electrode.

<Positive electrode>
As the positive electrode active material, a mixture of LiMn ₂ O ₄ and LiNiO ₂ at a weight ratio of 7: 3 was used. This positive electrode active material, carbon black as a conductive auxiliary material, and polyvinylidene fluoride as a positive electrode binder were weighed at a mass ratio of 90: 5: 5. These were mixed with N-methylpyrrolidone to prepare a positive electrode slurry. The positive electrode slurry was applied to an aluminum foil having a thickness of 20 μm, dried, and further pressed to produce a positive electrode.

<Electrode laminate>
The obtained positive electrode 3 layers and negative electrode 4 layers were alternately stacked while sandwiching a polypropylene porous film as a separator. The ends of the positive electrode current collector not covered with the positive electrode active material and the negative electrode current collector not covered with the negative electrode active material were welded. Furthermore, the positive electrode terminal made from aluminum and the negative electrode terminal made from nickel were each welded to the welding location, and the electrode laminated body which has a planar laminated structure was obtained.

<Electrolyte>
A mixed solvent of EC and DEC (volume ratio: EC / DEC = 30/70) was used as the non-aqueous solvent. The compound (101) and LiPF ₆ are adjusted so that the concentration of LiPF ₆ as the supporting salt in the electrolyte is 1 M so that the content of the compound (101) as the additive in the electrolyte is 5% by mass. Were respectively added to the mixed solvent to prepare an electrolytic solution.

<Secondary battery>
The electrode laminate was accommodated in an aluminum laminate film as an exterior body, and an electrolyte solution was injected into the exterior body. Thereafter, the outer package was sealed while reducing the pressure to 0.1 atm to produce a secondary battery.

<Evaluation>
(Capacity maintenance rate at 45 ° C., volume increase rate)
The manufactured secondary battery was subjected to a charge / discharge test in a voltage range of 2.5 V to 4.2 V in a thermostat kept at 45 ° C., and the cycle retention rate (%) and the volume increase rate (%) Was evaluated. Charging was performed at a constant voltage of 1 C up to 4.2 V, followed by a constant voltage charge for 2.5 hours in total. The discharge was a constant current discharge to 2.5V at 1C.

“Capacity maintenance ratio (%)” was calculated by (discharge capacity after 200 cycles) / (discharge capacity after one cycle) × 100 (unit:%).

“Volume increase rate (%)” was calculated by {(volume capacity after 200 cycles) / (volume capacity before cycle start) −1} × 100 (unit:%).

The results are shown in Table 2.

(Examples 2 to 15)
A secondary battery was prepared and evaluated in the same manner as in Example 1 except that the compounds ((102) to (115)) shown in Table 2 were used as additives instead of the compound (101). The results are shown in Table 2.

(Comparative Example 1)
A secondary battery was prepared and evaluated in the same manner as in Example 1 except that the following compound (201) was used instead of the compound (101) as an additive. The results are shown in Table 2.

(Comparative Example 2)
A secondary battery was prepared and evaluated in the same manner as in Example 1 except that the following compound (202) (1,3-propane sultone) was used instead of the compound (101) as an additive. The results are shown in Table 2.

This application claims priority based on Japanese Patent Application No. 2013-190744 filed on September 13, 2013, the entire disclosure of which is incorporated herein.

As mentioned above, although this invention was demonstrated with reference to embodiment and an Example, this invention is not limited to the said embodiment and Example. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

This embodiment can be used in all industrial fields that require a power source and in industrial fields related to the transport, storage, and supply of electrical energy. Specifically, power supplies for mobile devices such as mobile phones and notebook computers; power supplies for transportation and transportation media such as trains, satellites, and submarines, including electric vehicles such as electric cars, hybrid cars, electric bikes, and electric assist bicycles A backup power source such as a UPS; a power storage facility for storing power generated by solar power generation, wind power generation, etc .;

a negative electrode b separator c positive electrode d negative electrode current collector e positive electrode current collector f positive electrode terminal g negative electrode terminal

Claims

A compound represented by the following formula (1);

(In Formula (1), R 1 represents a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms which may be branched. R 2 represents a single bond or a substituted or unsubstituted group which may be branched. And represents a substituted alkylene group having 1 to 5 carbon atoms.).
In the formula (1), the substituent of R 1 is an optionally branched alkyl group, an optionally branched halogen-substituted alkyl group, an optionally branched alkenyl group, and an optionally branched alkynyl group. , An optionally branched alkoxy group, an amino group, a hydroxy group, or a halogen atom, and the substituent of R 2 is an optionally branched alkyl group, an optionally branched halogen substituted alkyl group, a branched group The compound according to claim 1, which is an alkenyl group which may be branched, an alkynyl group which may be branched, an alkoxy group which may be branched, an amino group, a hydroxy group, or a halogen atom.
In the formula (1), the substituent of R 1 is an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, and optionally substituted halogen atoms having 1, 2, 3 or 4 carbon atoms. An alkyl group, an optionally branched alkenyl group having 2, 3 or 4 carbon atoms, an optionally branched alkynyl group having 2, 3 or 4 carbon atoms, an optionally branched carbon number 1, 2, 3 Or an alkoxy group having 4 atoms, an amino group, a hydroxy group, or a halogen atom, and the substituent of R 2 may be branched, an alkyl group having 1, 2, 3 or 4 carbon atoms, or may be branched. A halogen-substituted alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched alkenyl group having 2, 3 or 4 carbon atoms, an optionally branched alkynyl group having 2, 3 or 4 carbon atoms, branched May have 1 carbon 2, 3 or 4 alkoxy groups, amino group, hydroxy group, or a halogen atom A compound according to claim 1.
In the formula (1), the substituent of R 1 is an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, and optionally substituted fluorine atom having 1, 2, 3 or 4 carbon atoms. An alkyl group or a fluorine atom, and the substituent of R 2 may be branched, may have 1, 2, 3 or 4 carbon atoms, may be branched, 1, 2, 3 or 4 carbon atoms The compound according to claim 1, which is a fluorine-substituted alkyl group or a fluorine atom.
The compound of Claim 1 represented by following formula (2);

(In the formula (2), m is an integer of 1, 2, 3, or 4. n is an integer of 0, 1, 2, 3, or 4. R 11 and R 12 are each independently A hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched fluorine substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom. 11 and R 12 are each independent for each carbon atom to which they are bonded, and R 13 and R 14 are each independently a hydrogen atom or an optionally branched alkyl having 1, 2, 3 or 4 carbon atoms. A group, an optionally branched fluorine-substituted alkyl group having 1, 2, 3 or 4 carbon atoms, or a fluorine atom, each of R 13 and R 14 is independent for each bonded carbon atom. .
The compound of Claim 1 represented by following formula (3);

(In Formula (3), R 101 and R 102 are each independently a hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched carbon number 1, 2, 3 or 4 fluorine-substituted alkyl groups, or fluorine atoms).
The compound of Claim 1 represented by following formula (4);

(In Formula (4), R 201 and R 202 are each independently a hydrogen atom, an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms, an optionally branched carbon number 1, A fluorine-substituted alkyl group having 2, 3 or 4 or a fluorine atom, and R 203 and R 204 are each independently a hydrogen atom or an optionally branched alkyl group having 1, 2, 3 or 4 carbon atoms. is there.).
The compound according to claim 1, which is represented by any one of the following formulas (101) to (115);
An electrolyte solution comprising the compound according to any one of claims 1 to 8, a supporting salt, and a nonaqueous solvent.
The electrolyte solution according to claim 9, wherein the non-aqueous solvent contains carbonates.
The electrolytic solution according to claim 9 or 10, wherein the content of the compound in the electrolytic solution is 0.1 to 10% by mass.
A secondary battery comprising the electrolytic solution according to any one of claims 9 to 11.
Furthermore, a positive electrode containing a positive electrode active material, and a negative electrode containing a negative electrode active material,
The positive electrode active material is a lithium composite oxide;
The negative electrode active material is lithium metal, metal (a) that can be alloyed with lithium, metal oxide (b) that can occlude and release lithium ions, or carbon material (c) that can occlude and release lithium ions. The secondary battery according to claim 12.
An electric vehicle comprising the secondary battery according to claim 12 or 13.
A power system comprising the secondary battery according to claim 12 or 13.
An electrolytic solution containing a nonaqueous solvent and a cyclic organic compound having at least two groups represented by the following formula (301).