JP2016058252A - Nonaqueous electrolyte power storage device and lithium ion secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte power storage device which has high charge and discharge efficiencies and high charge and discharge capacities, and which is superior in repeating cycle characteristics.SOLUTION: A nonaqueous electrolyte power storage device comprises: a positive electrode including a positive electrode active material which allows an anion to go thereinto and go out thereof; a negative electrode including a negative electrode active material which allows a cation to go thereinto and go out thereof; and a nonaqueous electrolytic solution arranged by dissolving an electrolytic salt in a nonaqueous solvent. The nonaqueous solvent includes 85.0-99.9 mass% of chain carbonate and 0.1-15.0 mass% of cyclic carbonate to the total mass of the nonaqueous solvent. The cyclic carbonate includes at least a fluorinated cyclic carbonate. The concentration of the electrolytic salt in the nonaqueous electrolytic solution is 2 mol/L or more.SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous electrolyte storage element and a lithium ion secondary battery.

  Conventionally, as a non-aqueous electrolyte secondary battery, a lithium ion secondary battery having a positive electrode such as a lithium cobalt composite oxide, a carbon negative electrode, and a non-aqueous electrolyte obtained by dissolving a lithium salt in a non-aqueous solvent Is often used. In recent years, it has been used for a wide range of applications from portable devices to electric vehicles, and high energy density has been demanded.

  On the other hand, using a material such as a conductive polymer or carbonaceous material for the positive electrode, anions in the non-aqueous electrolyte are inserted or removed from the positive electrode, and lithium ions in the non-aqueous electrolyte are inserted into the negative electrode made of a carbonaceous material. There is a non-aqueous electrolyte secondary battery (hereinafter, this type of battery is sometimes referred to as “dual carbon battery (DCB)”) that is charged and discharged by desorption (Non-Patent Document 1). reference). The discharge capacity of the DCB is determined by the anion storage amount of the positive electrode, the anion release amount of the positive electrode, the cation storage amount of the negative electrode, the cation release amount of the negative electrode, the anion amount and the cation amount in the non-aqueous electrolyte.

In order to increase the discharge capacity, a large amount of ions in the electrolytic solution is required. Therefore, a large amount of electrolyte is required at a concentration of about 1 M that is normally used in Li batteries, leading to a decrease in weight energy density. As an improvement measure, the amount of the electrolyte may be reduced, that is, a high concentration electrolyte may be used. However, there is a problem that the viscosity is high in the high concentration electrolytic solution, and in order to use the high concentration electrolytic solution for DCB, it is necessary to lower the viscosity of the electrolytic solution.
Cyclic carbonates and chain carbonates are known as nonaqueous solvents for nonaqueous electrolytic solutions.
Since the chain carbonate has a lower viscosity than the cyclic carbonate, it can be used as an electrolytic solution even at a high concentration by increasing the use ratio of the chain carbonate.

  By setting the ratio of the chain carbonate to 100%, the viscosity of the electrolytic solution can be reduced, the concentration of the electrolytic solution can be increased, and a high charge / discharge capacity can be obtained, but the charge / discharge efficiency is reduced. End up. In order to achieve high charge / discharge efficiency, formation of SEI (Solid Electrolyte Interface) is effective. A non-conductive film called SEI is formed to protect the electrode during the first charge / discharge. This prevents the negative electrode from decomposing and degrading due to a strong reduction reaction during charging, and preventing the nonaqueous electrolyte from decomposing and generating gas. Cyclic carbonate is effective for this SEI formation. However, when the ratio exceeds 20% by mass of the entire non-aqueous solvent, the charge / discharge capacity is reduced. Furthermore, fluorinated cyclic carbonates are particularly effective for SEI formation, and electrolytic solutions to which fluorinated cyclic carbonates are added have been proposed (see Patent Documents 1 to 6).

  However, these contain 30% by mass or more of the non-fluorinated cyclic carbonate in the whole non-aqueous solvent. As described above, in DCB, when the proportion of cyclic carbonate in the high concentration electrolyte increases, the capacity decreases.

An object of the present invention is to solve the above-described problems and achieve the following objects.
That is, an object of the present invention is to provide a nonaqueous electrolyte storage element that has high charge / discharge efficiency and charge / discharge capacity and is excellent in repeated cycle characteristics.

The inventor of the present invention has a concentration of an electrolyte solution component containing 85 to 99.9% by mass of a linear carbonate and 0.1 to 14.9% by mass of a cyclic carbonate containing at least a fluorinated cyclic carbonate of 2M or more, The present invention has been completed by finding that the above-mentioned problems can be solved by using a nonaqueous electrolytic solution containing 0.1 to 10% by mass of ethylene carbonate.
That is, the present invention is a nonaqueous storage element as described in (1) below.

(1) A non-aqueous electrolyte solution comprising a positive electrode active material capable of inserting or removing anions, a negative electrode containing a negative electrode active material capable of inserting or removing cations, and an electrolyte salt dissolved in a non-aqueous solvent A non-aqueous electrolyte storage element comprising:
The non-aqueous solvent contains 85.0-99.9% by weight of chain carbonate and 0.1-15.0% by weight of cyclic carbonate with respect to the total amount of the non-aqueous solvent,
The cyclic carbonate includes at least a fluorinated cyclic carbonate,
The concentration of the electrolyte salt in the non-aqueous electrolyte is 2 mol / L or more.

  The nonaqueous electrolyte storage element of the present invention has high charge / discharge efficiency and charge / discharge capacity, and has the effect of being excellent in repeated cycle characteristics.

It is a figure which shows the change of the discharge capacity when 100 charge / discharge cycles are performed about the non-aqueous-electrolyte electrical storage element of an Example. It is a figure which shows the change of the discharge capacity when 100 charge / discharge cycles are performed about the non-aqueous-electrolyte electrical storage element of an Example.

The present invention relates to the following non-aqueous electrolyte storage element (1), and includes the following (2) to (10) as embodiments.
(1) A non-aqueous electrolyte solution comprising a positive electrode active material capable of inserting or removing anions, a negative electrode containing a negative electrode active material capable of inserting or removing cations, and an electrolyte salt dissolved in a non-aqueous solvent A non-aqueous electrolyte storage element comprising:
The non-aqueous solvent contains 85.0-99.9% by weight of chain carbonate and 0.1-15.0% by weight of cyclic carbonate with respect to the total amount of the non-aqueous solvent,
The cyclic carbonate includes at least a fluorinated cyclic carbonate,
The concentration of the electrolyte salt in the non-aqueous electrolyte is 2 mol / L or more.
(2) The content ratio of the fluorinated cyclic carbonate in the non-aqueous solvent is 0.1 to 10.0% by mass, and the non-aqueous electrolyte storage element according to (1) above.
(3) The non-aqueous electrolyte storage element according to (1) or (2), wherein the chain carbonate contains 90% by mass or more of dimethyl carbonate (DMC).
(4) The nonaqueous electrolyte storage element according to any one of (1) to (3), wherein the concentration of the electrolyte salt in the nonaqueous electrolyte is 3 mol / L or more.
(5) The nonaqueous electrolyte storage element according to any one of (1) to (4), wherein the nonaqueous electrolyte contains a compound capable of chemically binding an anion containing a halogen atom.
(6) The compound capable of chemically binding an anion containing a halogen atom is tris (tetrafluorophenyl) borate (TPFPB) and / or tris (hexafluoroisopropyl) borate (THFIPB). (5) The nonaqueous electrolyte storage element according to (5).
(7) The nonaqueous electrolyte storage element according to any one of (1) to (6), wherein the negative electrode active material contains at least hard carbon or soft carbon.
(8) The nonaqueous electrolysis according to any one of the above (1) to (7), wherein the positive electrode active material and the negative electrode active material have a capacity ratio of 1: 1.5-1: 4. Liquid storage element.
(9) The nonaqueous electrolyte storage element according to any one of (1) to (8), wherein a maximum voltage during charge / discharge is 4.5 V or more and 6.0 V or less.
(10) A lithium ion secondary battery comprising the nonaqueous electrolyte storage element according to any one of (1) to (9), wherein the electrolyte salt is a lithium salt.

  Embodiments according to the present invention will be described below. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description exemplifies an embodiment of the present invention, and does not limit the scope of the claims.

The nonaqueous electrolyte storage element of the present invention includes a positive electrode including a positive electrode active material capable of inserting or desorbing anions, a negative electrode including a negative electrode active material composed of a carbon material capable of inserting or desorbing cations, and an electrolyte salt. And a non-aqueous electrolyte solution.
Hereinafter, the positive electrode, the negative electrode, the non-aqueous electrolyte, and the separator that constitute the non-aqueous electrolyte storage element will be sequentially described.

<Positive electrode>
The positive electrode is not particularly limited as long as it contains a positive electrode active material, and can be appropriately selected according to the purpose. For example, a positive electrode including a positive electrode material layer containing a positive electrode active material on a positive electrode current collector Is mentioned. There is no restriction | limiting in particular as a shape of the said positive electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

<< Cathode Material Layer >>
-Positive electrode active material-
The positive electrode active material is not particularly limited as long as it can insert or desorb anions, and can be appropriately selected according to the purpose. Examples thereof include carbonaceous materials and conductive polymers. . Among these, a carbonaceous material is particularly preferable because of its high energy density. Examples of the conductive polymer include polyaniline, polypyrrole, polyparaphenylene, and the like.

Examples of the carbonaceous material include graphite (graphite) such as coke, artificial graphite and natural graphite, and organic pyrolysis products under various pyrolysis conditions. Artificial graphite, natural graphite, and soft carbon are particularly preferable.
The carbonaceous material is preferably a carbonaceous material having high crystallinity. The crystallinity can be evaluated by X-ray diffraction, Raman analysis, or the like. For example, in a powder X-ray diffraction pattern using CuKα rays, diffraction peak intensity I _{2θ = 22.3 ° at 2θ = 22.3 °} and diffraction peak intensity I _{2θ = 26.4 ° at 2θ = 26.4 °.} And the intensity ratio I _{2θ = 22.3 °} / I _{2θ = 26.4 °} is preferably 0.4 or less.

The BET specific surface area by nitrogen adsorption of the carbonaceous material is preferably 1 m ² / g or more and 100 m ² / g or less, and the average particle size (median diameter) obtained by the laser diffraction / scattering method is 0.1 μm or more and 100 μm or less. Preferably there is.

Soft carbon is a general term for carbon in which a hexagonal network surface composed of carbon atoms, for example, by heat treatment under an inert atmosphere, can easily form a regular laminated structure. Preferred for the present invention is carbon that forms a crystal structure in which the average distance d002 of (002) planes is 3.50 mm or less, preferably 3.35-3.45 mm when heat-treated in an inert atmosphere. used.
Specific raw materials for soft carbon include graphitizable cokes such as petroleum pitch, coal-based pitch, coke, and anthracene. These may be used alone or in combination of two or more.

-Binder-
The binder is not particularly limited as long as it is a material that is stable with respect to the solvent and electrolyte used in the production of the electrode, and can be appropriately selected according to the purpose. For example, polyvinylidene fluoride (PVDF), polytetra Fluorine binders such as fluoroethylene (PTFE), acrylic binders, styrene-butadiene rubber (SBR), isoprene rubber, and the like. These may be used alone or in combination of two or more.

-Thickener-
Examples of the thickener include carboxymethyl cellulose (CMC), methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphate starch, casein, and sodium alginate. These may be used alone or in combination of two or more.

-Conductive agent-
Examples of the conductive agent include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black and acetylene black. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular in the average thickness of the said positive electrode material layer, Although it can select suitably according to the objective, 20 micrometers-300 micrometers are preferable and 40 micrometers-200 micrometers are more preferable. When the average thickness is 20 μm or more, a sufficient energy density is obtained, and when it is 300 μm or less, good load characteristics are obtained.

<< Positive electrode current collector >>
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of the said positive electrode electrical power collector, According to the objective, it can select suitably.
The material of the positive electrode current collector is not particularly limited as long as it is formed of a conductive material, and can be appropriately selected according to the purpose. For example, stainless steel, nickel, aluminum, copper, titanium , Tantalum, and the like. Among these, stainless steel and aluminum are particularly preferable.
There is no restriction | limiting in particular as a shape of the said positive electrode electrical power collector, According to the objective, it can select suitably.
The size of the positive electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous electrolyte storage element, and can be appropriately selected according to the purpose.

<< Method for Fabricating Positive Electrode >>
The positive electrode is obtained by applying a positive electrode material composition in a slurry form by adding the binder, the thickener, the conductive agent, a solvent, and the like to the positive electrode active material as necessary. It can be produced by drying to form a positive electrode material layer. There is no restriction | limiting in particular as said solvent, According to the objective, it can select suitably, For example, an aqueous solvent, an organic solvent, etc. are mentioned. Examples of the aqueous solvent include water, alcohol, and the like. Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), toluene, and the like.
In addition, the positive electrode active material can be roll-formed as it is to form a sheet electrode, or can be formed into a pellet electrode by compression molding.

<Negative electrode>
The negative electrode is not particularly limited as long as it contains a negative electrode active material, and can be appropriately selected according to the purpose. For example, a negative electrode including a negative electrode material layer containing a negative electrode active material on a negative electrode current collector, Etc.
There is no restriction | limiting in particular as a shape of the said negative electrode, According to the objective, it can select suitably, For example, flat form etc. are mentioned.

<< Anode Material Layer >>
The negative electrode material layer includes at least a negative electrode active material, and further includes a binder, a conductive agent, and the like as necessary.

-Negative electrode active material-
The negative electrode active material is not particularly limited as long as it is a substance capable of inserting or removing a cation, and can be appropriately selected according to the purpose. For example, an alkali metal ion, an alkaline earth metal or occlusion thereof, Releasable metal oxides; alkali metal ions, metals that can be alloyed with alkaline earth metals, alloys containing these metals, composite alloy compounds; non-reactive electrodes by physical adsorption of ions such as carbonaceous materials with a high specific surface area , Etc. Among these, a substance capable of inserting or removing at least one of lithium and lithium ions is preferable in terms of energy density, and a non-reactive electrode is more preferable in terms of cycle characteristics.

  Specifically, the negative electrode active material can be alloyed with lithium such as carbonaceous material, antimony tin oxide, lithium metal oxide such as silicon monoxide, lithium, such as aluminum, tin, silicon and zinc. Or a metal alloy capable of being alloyed with lithium, a composite alloy compound of lithium and an alloy containing the metal, and lithium metal nitride such as cobalt lithium nitride. These may be used individually by 1 type and may use 2 or more types together. Among these, carbonaceous materials are particularly preferable from the viewpoint of safety and cost.

Examples of the carbonaceous material include graphite (graphite) such as coke, artificial graphite and natural graphite, and pyrolysis products of organic substances under various pyrolysis conditions. Among these, artificial graphite, natural graphite, and the above-mentioned soft carbon or hard carbon are particularly preferable.
As the hard carbon preferable in the present invention, for example, carbon that forms a crystal structure having an average interplanar spacing d002 of (002) plane exceeding 3.50 mm when heat-treated in an inert atmosphere. Specific examples of hard carbon materials include thermosetting resins such as phenol resin, melamine resin, urea resin, epoxy resin, and urethane resin, and carbon black such as acetylene black and furnace black.

-Binder--
There is no restriction | limiting in particular as said binder, According to the objective, it can select suitably, For example, fluorine-type binders, such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber ( EPBR), styrene-butadiene rubber (SBR), isoprene rubber, carboxymethylcellulose (CMC), and the like. These may be used alone or in combination of two or more.

-Conductive agent-
Examples of the conductive agent include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black and acetylene black. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the average thickness of the said negative electrode material layer, Although it can select suitably according to the objective, 10 micrometers-450 micrometers are preferable and 20 micrometers-200 micrometers are more preferable. When the average thickness is 10 μm or more, the cycle characteristics are good, and when it is 450 μm or less, a sufficient energy density is obtained.

<< Negative electrode current collector >>
There is no restriction | limiting in particular as a material, a shape, a magnitude | size, and a structure of the said negative electrode collector, According to the objective, it can select suitably.
The material of the negative electrode current collector is not particularly limited as long as it is formed of a conductive material, and can be appropriately selected according to the purpose. For example, stainless steel, nickel, aluminum, copper, etc. Is mentioned. Among these, stainless steel and copper are particularly preferable.
There is no restriction | limiting in particular as a shape of the said negative electrode electrical power collector, According to the objective, it can select suitably.
The size of the negative electrode current collector is not particularly limited as long as it is a size that can be used for a non-aqueous electrolyte storage element, and can be appropriately selected according to the purpose.

<< Method for Manufacturing Negative Electrode >>
The negative electrode is prepared by applying a negative electrode material composition in a slurry form by adding the binder, the conductive agent, a solvent, or the like to the negative electrode active material, if necessary, and drying the negative electrode current collector. It can be produced by forming a material layer. As the solvent, the same solvent as that for the positive electrode can be used.
Further, the negative electrode active material added with the binder, the conductive agent and the like is roll-formed as it is to form a sheet electrode, a pellet electrode by compression molding, the negative electrode current collector by techniques such as vapor deposition, sputtering, and plating. A thin film of the negative electrode active material can be formed on the body.

<Non-aqueous electrolyte>
The nonaqueous electrolytic solution is an electrolytic solution containing a nonaqueous solvent and an electrolyte salt.
<< Non-aqueous solvent >>
As the non-aqueous solvent, a chain carbonate that is an aprotic organic solvent and a cyclic carbonate are used in combination.
The non-aqueous solvent contains at least a fluorinated cyclic carbonate as the cyclic carbonate.
Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propionate (MP), and the like. Among these, dimethyl carbonate (DMC) is preferable.
Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), and vinylene carbonate (VC).

Content of the said chain carbonate shall be 85.0 mass% or more and 99.9 mass% or less with respect to the said non-aqueous solvent. Preferably they are 90 mass% or more and 99.9 mass% or less.
Moreover, content of the said cyclic carbonate shall be 0.1-15.0 weight% with respect to the said non-aqueous solvent.

  When the chain carbonate content is less than 85.0% by mass, when the remaining solvent is a cyclic substance (cyclic carbonate, cyclic ester, etc.) having a high dielectric constant, Because the amount increases, the viscosity becomes too high when a high concentration non-aqueous electrolyte solution of 3 mol / L or more is produced, which may cause problems in terms of penetration of the non-aqueous electrolyte solution into the electrode and ion diffusion. is there.

  When dimethyl carbonate (DMC) is used as the chain carbonate and ethylene carbonate (EC) is used as the cyclic carbonate, the mixing ratio of dimethyl carbonate (DMC) and ethylene carbonate (EC) is a mass ratio (DMC: EC) is preferably 85.0: 15.0-99.0: 1.0, more preferably 90.0: 10.0-99.0: 1.0.

As a content rate of a fluorinated cyclic carbonate, 0.1-10.0 mass% is preferable with respect to a non-aqueous solvent. When the content ratio of the fluorinated cyclic carbonate is 10.0% by mass or less, the viscosity of the solvent does not become too high. In addition, when the content ratio of the fluorinated cyclic carbonate is 0.1% or more, a sufficient charge / discharge efficiency improvement effect can be obtained.
Examples of the fluorinated cyclic carbonate include 4-fluoroethylene carbonate (FEC), 4,4-difluoroethylene carbonate, 4,5 difluorocarbonate, and trifluoropropylene carbonate.

  In addition, as said non-aqueous solvent, ester type organic solvents, such as cyclic ester and chain ester, ether type organic solvents, such as cyclic ether and chain ether, etc. can be used as needed.

Examples of the cyclic ester include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, and γ-valerolactone.
Examples of the chain ester include propionic acid alkyl ester, malonic acid dialkyl ester, acetic acid alkyl ester (methyl acetate (MA), ethyl acetate, etc.), formic acid alkyl ester (methyl formate (MF), ethyl formate, etc.), etc. Is mentioned.
Examples of the cyclic ether include tetrahydrofuran, alkyltetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane, and the like.
Examples of the chain ether include 1,2-dimethoxyethane (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, and tetraethylene glycol dialkyl ether.

<< Electrolyte salt >>
The electrolyte salt is not particularly limited as long as it contains a halogen atom, dissolves in a non-aqueous solvent and exhibits high ionic conductivity, and a combination of the following cation and the following anion can be used. It is.

Examples of the cation include alkali metal ions, alkaline earth metal ions, tetraalkylammonium ions, spiro quaternary ammonium ions, and the like.
Examples of the anion include Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N. _{^{-, (C 2 F 5 SO}} 2) 2 N -, and the like.

Among the electrolyte salts containing halogen atoms, lithium salts are particularly preferable from the viewpoint of improving battery capacity.
The lithium salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, lithium hexafluorophosphate (LiPF ₆ ), lithium perchlorate (LiClO ₄ ), lithium chloride (LiCl), boron Lithium fluoride (LiBF ₄ ), lithium hexafluoroarsenide (LiAsF6), lithium trifluorometasulfonate (LiCF ₃ SO ₃ ), lithium bistrifluoromethylsulfonylimide (LiN (C ₂ F ₅ SO ₂ ) ₂ ), lithium And bisferfluoroethylsulfonylimide (LiN (CF ₂ F ₅ SO ₂ ) ₂ ). These may be used individually by 1 type and may use 2 or more types together. Among these, LiPF ₆ is particularly preferable from the viewpoint of the amount of occlusion of anions in the carbon electrode.

  There is no restriction | limiting in particular as content of the said electrolyte salt, Although it can select suitably according to the objective, 2 mol / L or more is preferable in the said nonaqueous solvent, and 2.5 mol / L-6 mol / L is preferable. More preferably, 2.5 mol / L-4 mol / L is more preferable from the viewpoint of achieving both the capacity and output of the electricity storage element.

<Separator>
The separator is provided between the positive electrode and the negative electrode in order to prevent a short circuit between the positive electrode and the negative electrode.
There is no restriction | limiting in particular as a material of the said separator, a shape, a magnitude | size, and a structure, According to the objective, it can select suitably.
Examples of the material of the separator include paper such as kraft paper, vinylon mixed paper, synthetic pulp mixed paper, cellophane, polyethylene graft film, polyolefin nonwoven fabric such as polypropylene melt flow nonwoven fabric, polyamide nonwoven fabric, and glass fiber nonwoven fabric. .
Among these, those having a porosity of 50% or more are preferable from the viewpoint of holding the non-aqueous electrolyte.
As the shape of the separator, the nonwoven fabric type is preferable from the point of high porosity than the thin film type having micropores.

There is no restriction | limiting in particular in the average thickness of the said separator, Although it can select suitably according to the objective, 20 micrometers-100 micrometers are preferable. When the average thickness is less than 20 μm, the retained amount of the electrolytic solution may be reduced, and when it exceeds 100 μm, the energy density is reduced.
More preferably, a microporous film (micropore film) of 30 μm or less is arranged on the negative electrode side to prevent a positive / negative short circuit due to precipitation of alkali metal or alkaline earth metal on the negative electrode side, and the thickness is 20 μm− on the positive electrode side. It is preferable to use a non-woven fabric with a porosity of 100 μm and a porosity of 50% or more.
Examples of the shape of the separator include a sheet shape.
There is no restriction | limiting in particular as long as the magnitude | size of the said separator is a magnitude | size which can be used for a non-aqueous electrolyte electrical storage element, It can select suitably according to the objective.

<Other members>
There is no restriction | limiting in particular as said other member, According to the objective, it can select suitably, For example, an armored can, an electrode extraction line, etc. are mentioned.

<Method for Manufacturing Nonaqueous Electrolyte Storage Element>
The non-aqueous electrolyte storage element of the present invention is manufactured by assembling the positive electrode, the negative electrode, and the non-aqueous electrolyte and a separator used as necessary into an appropriate shape. Furthermore, it is also possible to use other components such as an outer can if necessary. There is no restriction | limiting in particular as a method of assembling the said non-aqueous electrolyte electrical storage element, It can select suitably from the methods employ | adopted normally.

  The non-aqueous electrolyte storage element of the present invention is not particularly limited and can be appropriately selected according to the purpose. However, the maximum voltage during charge / discharge is preferably 4.5V-6.0V. If the maximum voltage at the time of charging / discharging is less than 4.5V, the anion cannot be sufficiently accumulated and the capacity may be lowered. If it exceeds 6.0V, the solvent and the electrolyte salt are not easily decomposed and deteriorated. May be faster.

  4.5-6.0V at the time of charging / discharging of this nonaqueous electrical storage element is desirable. In charge / discharge under a high voltage, HF is generated due to decomposition of the electrolyte. This HF causes deterioration of the negative electrode. Therefore, the capacity ratio of the positive electrode and negative electrode active material is 1: 1.5-1: 4, that is, the negative electrode capacity is larger than the positive electrode capacity. It becomes possible. Further, when the capacity of the negative electrode is four times or more of the capacity of the positive electrode, the energy density tends to decrease.

<Compound having a site capable of binding an anion containing a halogen atom>
The compound having a site capable of binding an anion containing a halogen atom is not particularly limited as long as it can bind to an anion containing a halogen atom, and can be appropriately selected depending on the purpose. Chemically bondable compounds are preferred.
The compound having a moiety capable of binding an anion containing a halogen atom (hereinafter also referred to as “anion receptor”) is not particularly limited and may be appropriately selected depending on the intended purpose. Examples include ether compounds, azaether compounds, inclusion compounds such as cyclodextrin, alkyl boron fluoride compounds, phenyl boron fluoride, and the like. Among these, a compound having a coordination ability for a relatively small anion is preferable. In the present invention, a compound having a coordination ability for a relatively small anion is preferred because it aims at capturing an anion containing a halogen atom which is a smaller element (particularly an anion containing a fluorine atom). An anion receptor capable of capturing a large anion is not preferable because it can also capture an anion such as PF _6- ^{and the} like, which lowers the anion transport efficiency in the battery.

  The compound having a coordination ability to the relatively small anion has an element having an anion coordination ability and increases the anion capturing ability, so that the electron density of the element having the anion coordination ability is lowered. It is a compound having a substituent. As a result, an element having anion coordination ability can function as a strong Lewis acidic site, and can efficiently capture the fluorine component as a Lewis base. For example, tertiary boron is the main functional skeleton, and the substituent is halogen atom, fluorine-substituted alkyl group, fluorine-substituted alkoxy group, fluorine-substituted aryl group, fluorine-substituted phenoxy group, fluorine-substituted allyl A compound having a group or the like is used. A compound having tertiary nitrogen as the main functional skeleton can also be used. Among these, a compound having a substituent (particularly a fluorine substituent) having tertiary boron as a main functional skeleton and an electron withdrawing ability is particularly preferable from the viewpoint of high Lewis acid ability.

  The compound having a site capable of binding an anion containing a halogen atom is at least one selected from a compound represented by the following general formula (1) and a compound represented by the general formula (2). Is preferred.

<Compound of general formula (1)>
First, the compound represented by the following general formula (1) will be described.

In the general formula (1), R ¹ , R ² and R ³ may be the same as or different from each other, and represent any one of an alkyl group, an aryl group, and a heteroaryl group. May be substituted with any of a halogen atom, an alkyl group, an alkoxide group, a thiol group, a thioalkoxide group, an aryl group, an ether group and a thioether group.

The alkyl group is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms. Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tertiary butyl group, pentyl group, isopentyl group, hexyl group, isohexyl group, heptyl group, isoheptyl group, octyl group, isooctyl group , Nonyl group, isononyl group, cyclopentyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, and the like.

  The aryl group preferably has 6 to 12 carbon atoms, and examples thereof include a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a styryl group, a mesityl group, a cinnamyl group, a phenethyl group, a benzhydryl group, and a naphthyl group. A phenyl group is particularly preferred.

Examples of the heteroaryl group include a thienyl group, a pyridyl group, an indolyl group, and the like.
Examples of the halogen atom include a chlorine atom, a bromine atom, and a fluorine atom, and a fluorine atom is particularly preferable.

In the case where R ¹ , R ² and R ³ have a cyclic structure, those having a cyclic structure having an aromatic property are preferred, and the bond with boron is bonded directly to a cyclic compound having an aromatic property, or It is preferable that it couple | bonds through the substituent which can form a conjugated system with a cyclic compound. Further, the substituent bonded to the cyclic compound is preferably a substituent having an electron withdrawing function and a function of lowering the electron density of the ring.

Among these, in the general formula (1), R ¹ , R ² and R ³ are preferably the same group, more preferably a phenyl group, and part or all of the five hydrogen atoms of the phenyl group are all More preferably, it is substituted with fluorine, and —C ₆ F ₅ in which all five hydrogen atoms of the phenyl group are substituted with fluorine atoms has an electron-deficient state induced by a fluorine atom having high electronegativity. This is particularly preferable because it can be delocalized on the ring and can also interact with the electron orbital of boron, which is the central element, and can effectively reduce the electron density on boron.

  The compound represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the compound represented by the following structural formula (1-1) (tris (penta Fluorophenyl) borane: TPFPB), trimesitylborane, tris (1,2-dimethylpropyl) borane, tris (parafluorophenyl) borane, tris (parachlorophenyl) borane, and the like. Among these, TPFPB represented by the following structural formula (1-1) is preferable from the viewpoint of coordination ability to anions.

<Compound of general formula (2)>
Next, the compound represented by the following general formula (2) will be described.

In the general formula (2), R ⁴ , R ⁵ and R ⁶ may be the same as or different from each other, and represent any one of an alkyl group, an aryl group, and a heteroaryl group. May be substituted with any of a halogen atom, an alkyl group, an alkoxide group, a thiol group, a thioalkoxide group, an aryl group, an ether group and a thioether group.

Examples of the alkyl group, aryl group, and heteroaryl group include those similar to the alkyl group, aryl group, and heteroaryl group of the general formula (1). Examples of the halogen atom include a chlorine atom, a bromine atom, and a fluorine atom, and a fluorine atom is particularly preferable.
Among these, in the general formula (2), R ⁴ , R ⁵ and R ⁶ are preferably the same, more preferably an alkyl group having 2 to 3 carbon atoms, and hydrogen of an alkyl group having 2 to 3 carbon atoms. Those in which some or all of the atoms are substituted with fluorine atoms are more preferred, and those in which all of the hydrogen atoms of the alkyl group having 2 to 3 carbon atoms are substituted with fluorine atoms lower the electron density of boron as the central element. It is particularly preferable from the viewpoint.

Examples of the compound represented by the general formula (2) is not particularly limited and may be appropriately selected depending on the purpose, for _{example, (CH 3 O) 3 B} , (C 3 F 7 CH 2 O) 3 B, [(CF ₃ ) ₂ CHO] ₃ B, [(CF ₃ ) ₂ C (C ₆ H ₅ ) O] ₃ B, (C ₆ H ₅ O) ₃ B, (FC ₆ H ₄ O) ₃ B , (F ₂ C ₆ H ₃ O) ₃ B, (F ₄ C ₆ HO) ₃ B, (C ₆ F ₅ O) ₃ B, (CF ₃ C ₆ H ₄ O) ₃ B, [(CF ₃ ) ₂ C ₆ H ₃ O] ₃ B, compounds represented by the following structural formula (2-1) (tris (hexafluoroisopropyl) borate: THFIPB), (CF ₃ O) ₃ B, and the like. In particular, THFIPB represented by the following structural formula (2-1) is preferable.

  The content of the compound having a site capable of binding an anion containing a halogen atom is not particularly limited and may be appropriately selected depending on the intended purpose, but is 0.5% by mass or more based on the non-aqueous electrolyte. Preferably, 0.5 mass%-5 mass% are more preferable, and 1 mass%-3 mass% are still more preferable. When the content is less than 0.5% by mass, it may be difficult to obtain the effect. When the content exceeds 5% by mass, the ion diffusibility decreases due to an increase in viscosity and the charge / discharge efficiency decreases. There is.

  Note that the addition of a compound (for example, TPFPB) having a portion capable of binding an anion containing a halogen atom inside the non-aqueous electrolyte storage element decomposes the non-aqueous electrolyte storage element, resulting in non-aqueous electrolysis. The liquid can be analyzed by examining it with gas chromatography or the like.

<Shape>
There is no restriction | limiting in particular about the shape of the non-aqueous-electrolyte electrical storage element of this invention, According to the use, it can select suitably from the various shapes generally employ | adopted. Examples of the shape include a laminate type, a cylinder type in which a sheet electrode and a separator are spiral, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, and a coin type in which a pellet electrode and a separator are stacked. .

<Application>
The use of the non-aqueous electrolyte storage element of the present invention is not particularly limited and can be used for various purposes. For example, a notebook computer, pen input personal computer, mobile personal computer, electronic book player, mobile phone, mobile fax, mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, motor, lighting equipment, toy, game Equipment, watches, strobes, cameras, electric bicycles, electric tools, etc.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
Further, in the following description, unless otherwise specified, parts indicate parts by mass and% indicates mass%.

<Production Example 1 of Positive Electrode>
-Production of positive electrode A-
Carbon powder (manufactured by TIMCAL, KS-6: graphite) was used as the positive electrode active material. This carbon powder had a BET specific surface area of 20 m ² / g by nitrogen adsorption and an average particle diameter (median diameter) measured by a laser diffraction particle size distribution meter (SALD-2200, manufactured by Shimadzu Corporation) was 3.4 μm.
Carbon powder (manufactured by TIMCAL, KS-6) 10.0 g and a conductive agent (acetylene black) 0.75 g are added and kneaded, and further 19 g of carboxymethyl cellulose (CMC) 2 mass% aqueous solution is added as a thickener. And kneaded. Subsequently, a binder (manufactured by JSR) (0.75 g) was added and kneaded to prepare a positive electrode material layer composition (slurry). The positive electrode material composition was coated on an aluminum foil and vacuum dried at 120 ° C. for 5 minutes to form a positive electrode material layer. This was punched into a round shape with a diameter of 16 mm to produce a positive electrode A. At this time, the mass of the carbon powder (graphite) in the positive electrode material layer coated on the aluminum (Al) foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 1>
-Production of negative electrode A-
Carbon powder (manufactured by Hitachi Chemical Co., Ltd., MAGD: graphite) was used as the negative electrode active material. This carbon powder has a BET specific surface area of 4.5 m ² / g by nitrogen adsorption, an average particle diameter (median diameter) measured by a laser diffraction particle size distribution meter (SALD-2200, manufactured by Shimadzu Corporation), and a tap density of 630 kg. / M ³ .
Water was added to and kneaded with 10 g of carbon powder (graphite) and 0.5 g of a conductive agent (acetylene black), and 10 g of a 2% by weight aqueous solution of carboxymethyl cellulose (CMC) was further added and kneaded as a thickener. Subsequently, a binder (manufactured by Denki Kagaku Kogyo Co., Ltd.) 50.2 mass% aqueous solution 0.6 g was added to prepare a negative electrode material layer composition (slurry). The negative electrode material layer composition was applied to a Cu foil and vacuum dried at 120 ° C. for 5 minutes to form a negative electrode material layer. This was punched into a round shape with a diameter of 16 mm to obtain a negative electrode A. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 2>
-Production of negative electrode B-
Soft carbon (manufactured by Hitachi Chemical Co., Ltd., SMC) was used as the negative electrode active material. The carbon powder of BET has a BET specific surface area of 2.7 m ² / g by nitrogen adsorption, an average particle size (median diameter) measured by a laser diffraction particle size distribution meter (SALD-2200, manufactured by Shimadzu Corporation), and a tap density of 910 kg. / M ³ .
Negative electrode B was prepared by the same production method as negative electrode A. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 3>
-Production of negative electrode C-
Hard carbon (Sumitomo Bakelite Co., Ltd., LVB-1001) was used as the negative electrode active material. This carbon powder has a BET specific surface area of 2.9 m ² / g by nitrogen adsorption, an average particle diameter (median diameter) measured by a laser diffraction particle size distribution meter (SALD-2200, manufactured by Shimadzu Corporation), and a tap density of 900 kg. / M ³ .
A negative electrode C was prepared in the same manner as the negative electrode A. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 4>
-Production of negative electrode D-
As the negative electrode active material, MAGD and hard carbon were mixed at a mass ratio of 7: 3.
It was prepared by adding 10 g of a mixture of MAGD and hard carbon in a mass ratio of 7: 3 instead of MAGD by the same production method as that for negative electrode A. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 5>
-Production of negative electrode E-
As the negative electrode active material, MAGD and hard carbon were mixed at a mass ratio of 5: 5. It was prepared by adding 10 g of a mixture of MAGD and hard carbon at a mass ratio of 5: 5 instead of MAGD by the same production method as that for negative electrode A. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.

<Negative electrode production example 6>
-Production of negative electrode F-
As the negative electrode active material, MAGD and hard carbon were mixed at a mass ratio of 3: 7. In the same production method as that of the negative electrode A, 10 g of a mixture of MAGD and hard carbon in a mass ratio of 3: 7 was added instead of MAGD. At this time, the mass of the carbon powder (graphite) in the negative electrode material layer coated on the Cu foil having a diameter of 16 mm was 20 mg.
The structures of the positive electrode and the negative electrode obtained above are shown in Table 2 below.

<Production Example 1 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte A−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which dimethyl carbonate (DMC), ethylene carbonate (EC), and fluoroethylene carbonate (FEC) were mixed at a mass ratio of 88: 10: 2 was prepared.
In the following, dimethyl carbonate is abbreviated as “DMC”, ethylene carbonate as “EC”, and fluoroethylene carbonate as “FEC”.

<Production Example 2 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte B−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 96: 2: 2 was prepared.

<Production Example 3 of Nonaqueous Electrolyte>
-Preparation of non-aqueous electrolyte C-
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC and FEC were mixed at a mass ratio of 98: 2 was prepared.

<Production Example 4 of Nonaqueous Electrolyte>
-Preparation of non-aqueous electrolyte D-
20 mL of an electrolytic solution in which 3.0 mol / L LiPF ₆ was dissolved in a solution in which DMC and FEC were mixed at a mass ratio of 98: 2 was prepared.

<Production Example 5 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte E−
2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC and FEC were mixed at a mass ratio of 98: 2, and then tris (pentafluorophenyl) borane (TPFPB, manufactured by Tokyo Chemical Industry Co., Ltd., reagent product) was added thereto. By adding 20 mL of an electrolyte solution having a concentration of TPFPB of 1% by mass.

<Production Example 6 of Nonaqueous Electrolyte>
-Preparation of non-aqueous electrolyte F-
2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC and FEC were mixed at a mass ratio of 98: 2, and then tris (hexafluosoisopropyl) borate (THFIPB, manufactured by Tokyo Chemical Industry Co., Ltd., reagent product) THFIPB was added to prepare 20 mL of an electrolytic solution having a THFIPB concentration of 1% by mass.

<Production Example 7 of Nonaqueous Electrolyte>
-Production of non-aqueous electrolyte HG-
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in DMC was prepared.

<Production Example 8 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte H−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 88: 10: 2 was prepared.

<Nonaqueous electrolyte production example 9>
−Preparation of non-aqueous electrolyte I−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 85: 13: 2 was prepared.

<Production Example 10 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte J−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 78: 20: 2 was prepared.

<Production Example 11 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte K−
20 mL of an electrolytic solution in which 2.0 mol / L LiPF ₆ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 65: 33: 2 was prepared.

<Production Example 12 of Nonaqueous Electrolyte>
-Preparation of non-aqueous electrolyte L-
20 mL of an electrolytic solution in which 1.0 mol / L LiPF ₆ was dissolved in DMC was prepared.

<Production Example 13 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte M−
20 mL of an electrolytic solution in which 2.0 mol / L LiBF ₄ was dissolved in a solution in which DMC, γ-butyrolactone (GBL), and FEC were mixed at a mass ratio of 88: 10: 2 was prepared.

<Production Example 14 of Nonaqueous Electrolyte>
−Preparation of non-aqueous electrolyte N−
20 mL of an electrolytic solution in which 2.0 mol / L LiBF ₄ was dissolved in a solution in which DMC, EC, and FEC were mixed at a mass ratio of 96: 2: 2 was prepared.
The compositions of the non-aqueous electrolytes A to N are shown in Table 1.

<Separator>
A glass fiber separator (manufactured by ADVANTEC, GA-100 GLASS FIBER FILTER) having a thickness of 0.38 mm was prepared.

<Preparation of nonaqueous electrolyte storage element>
The positive electrode, the separator, the negative electrode, and the non-aqueous electrolyte solution are placed in a coin-type electric storage element manufacturing can (2032 type, manufactured by Hosen Co., Ltd.), and the can is caulked with a caulking device (Hosen Co., Ltd.). A nonaqueous electrolyte storage element was produced.

<Verification of positive electrode capacity>
-Positive electrode A capacity check-
In a coin can, lithium (Honjo Metal Co., Ltd., thickness: 200 μm) was placed as the positive electrode A, the separator, the non-aqueous electrolyte A, and the counter electrode to constitute a power storage device. This electricity storage device was charged to a charge end voltage of 5.2 V with a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . Then, the storage element after the initial charge and discharge, a constant current charging at a constant current of 1 mA / cm ² to 5.2V, then constant current discharge for discharging at a constant current of 1 mA / cm ² to 3.0V The charge / discharge cycle was performed twice, and the capacity per unit area of the positive electrode A was measured. As a result, it was 0.85 mAh / cm ² . In addition, it measured using the charging / discharging measuring apparatus (Toyo System Co., Ltd. make, TOSCAT3001).

<Confirmation of negative electrode capacity>
-Capacity check of negative electrode A-
In a coin can, the negative electrode A, the separator, the non-aqueous electrolyte A, and lithium (Honjo Metal Co., Ltd., thickness: 200 μm) were placed as a counter electrode to constitute a power storage device. This power storage element is charged to a charge end voltage of 0 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 1.5 V at a constant current of ² mA / cm ² . Then, the storage element after the initial charge / discharge is charged with a constant current of 1 mA / cm ² to 0 V, and then discharged with a constant current of 1 mA / cm ² to 1.5 V for one cycle. And this charge / discharge cycle is performed twice. When the capacity per unit area of the negative electrode A was measured, it was 3.41 mAh / cm ² . In addition, it measured using the charging / discharging measuring apparatus (Toyo System Co., Ltd. make, TOSCAT3001).

-Capacity check of negative electrode B-
In a coin can, lithium (Honjo Metal Co., Ltd., thickness: 200 μm) was put as the negative electrode B, the separator, the non-aqueous electrolyte A, and the counter electrode to constitute a power storage device. This power storage element is charged to a charge end voltage of 0 V at a constant current of ² mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 1.5 V at a constant current of ² mA / cm ² . Then, the storage element after the initial charge / discharge is charged with a constant current of 1 mA / cm ² to 0 V, and then discharged with a constant current of 1 mA / cm ² to 1.5 V for one cycle. And this charge / discharge cycle is performed twice. When the capacity per unit area of the negative electrode B was measured, it was 1.87 mAh / cm ² .

-Capacity check of negative electrode C-
In a coin can, the negative electrode F, the separator, the non-aqueous electrolyte A, and lithium (Honjo Metal Co., Ltd., thickness: 200 μm) are placed as a counter electrode to constitute a storage element, and charge / discharge under the same conditions as the negative electrode B I did it. The capacity per unit area of the negative electrode C was 1.89 mAh / cm ² .

-Capacity check of negative electrode D-
In a coin can, the negative electrode C, the separator, the non-aqueous electrolyte A, and lithium (Honjo Metal Co., Ltd., thickness: 200 μm) are placed as a counter electrode to constitute a storage element, and charge / discharge under the same conditions as the negative electrode B I did it. The capacity per unit area of the negative electrode C was 2.91 mAh / cm ² .

-Capacity check of negative electrode E-
In a coin can, the negative electrode D, the separator, the non-aqueous electrolyte A, and lithium (Honjo Metal Co., Ltd., thickness: 200 μm) are placed as a counter electrode to constitute a storage element, and charge / discharge under the same conditions as the negative electrode B I did it. The capacity per unit area of the negative electrode C was 2.63 mAh / cm ² .

-Capacity check of negative electrode F-
In a coin can, the negative electrode E, the separator, the non-aqueous electrolyte A, and lithium (made by Honjo Metal Co., Ltd., thickness: 200 μm) are placed as a counter electrode to constitute a storage element, and charge / discharge under the same conditions as the negative electrode B I did it. The capacity per unit area of the negative electrode C was 2.31 mAh / cm ² .
The constitution of the positive electrode and the negative electrode and the capacity per unit area are shown in Table 2 below.

[Example 1]
The positive electrode A, the negative electrode A, the separator, and the non-aqueous electrolyte C were placed in a coin can, and the non-aqueous electrolyte storage element of Example 1 was assembled. The obtained nonaqueous electrolyte storage element was charged to a charge end voltage of 5.2 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . Then, the storage element after the initial charge and discharge, a constant current charging at a constant current of 1 mA / cm ² to 5.2V, then constant current discharge to discharge with a constant current of 1 mA / cm ² to 3.0V One cycle was used. This cycle was performed 10 times. Among these, the charge / discharge efficiency of the 1st and 10th cycles was calculated. The results are shown in Table 1.
Here, the charge / discharge efficiency was calculated as (discharge capacity / charge capacity × 100)% using the charge and discharge capacity in the same cycle. In addition, it measured using the charging / discharging measuring apparatus (Toyo System Co., Ltd. make, TOSCAT3001). The results are shown in Table 3.

[Comparative Example 1]
The positive electrode A, the negative electrode A, the separator, and the non-aqueous electrolyte H were put in a coin can, and the non-aqueous electrolyte storage element of Comparative Example 1 was assembled. This element was subjected to charge / discharge measurement in the same manner as in Example 1, and the charge / discharge efficiency of the first and tenth cycles was calculated. The results are shown in Table 3.
From the comparison between Example 1 and Comparative Example 1, it can be seen that charging and discharging efficiency is improved by adding FEC to the electrolytic solution.

[Examples 2 and 3]
The positive electrode A, the negative electrode A, the separator, and the nonaqueous electrolytes A and B were placed in a coin can, and the nonaqueous electrolyte storage elements of Example 2 and Example 3 were assembled. This element was subjected to charge / discharge measurement in the same manner as in Example 1, and the charge / discharge efficiency of the first and tenth cycles was calculated. The results are shown in Table 4. Charge / discharge efficiency increased by adding EC and FEC.

[Examples 4 to 8]
The positive electrode A, the negative electrode A, the separator, and the non-aqueous electrolytes B and H to K were put in a coin can, and the non-aqueous electrolyte storage elements of Examples 4 to 8 were assembled.
The obtained nonaqueous electrolyte storage element was charged to a charge end voltage of 5.2 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . Table 5 shows the initial discharge capacity. As the proportion of EC increased, the initial discharge capacity decreased.

  From Examples 1 to 8, it was shown that the charge / discharge efficiency was increased by adding EC and FEC to the electrolytic solution, and that the charge / discharge capacity was reduced when the amount of EC added was too large.

[Examples 9 and 10]
The positive electrode A, the negative electrode A, the separator, and the nonaqueous electrolytes C and E were placed in a coin can, and the nonaqueous electrolyte storage elements of Examples 9 and 10 were assembled. About the obtained non-aqueous electrolyte storage element, the obtained non-aqueous electrolyte storage element was charged to a final charge voltage of 5.2 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . The results are shown in Table 6. It was shown that the charge / discharge capacity increases as the electrolyte concentration increases.

[Example 11]
The positive electrode A, the negative electrode B, the separator, and the nonaqueous electrolyte C were put in a coin can, and the nonaqueous electrolyte storage element of Example 11 was assembled. About the obtained nonaqueous electrolyte solution electrical storage element, it carried out similarly to Example 1, and performed the charging / discharging cycle 10 cycles. Of these, comparisons were made after 1, 10 cycles. The results are shown in Table 7.

[Comparative Example 2]
The positive electrode A, the negative electrode B, the separator, and the nonaqueous electrolyte solution G were put in a coin can, and the nonaqueous electrolyte storage element of Comparative Example 2 was assembled. The obtained nonaqueous electrolyte storage element was subjected to initial charge / discharge in the same manner as in Example 11 at room temperature (25 ° C.). The results are shown in Table 7.

  As shown in Example 11 and Comparative Example 2, even when soft carbon (SMC) was used as the negative electrode active material, the charge / discharge efficiency was improved by adding FEC.

[Examples 12 to 16]
The positive electrode A, the negative electrode BF, the separator, and the nonaqueous electrolyte solution B were placed in a coin can, and the nonaqueous electrolyte storage elements of Examples 12 to 16 were assembled. The obtained nonaqueous electrolyte storage element was subjected to initial charge / discharge in the same manner as in Example 5 at room temperature (25 ° C.). The results are shown in Table 8. The capacity was obtained even when graphite (MAGD) and hard carbon (HC) were mixed as the negative electrode. From these results, it was shown that hard carbon (HC) and soft carbon can be used for the negative electrode, and that an electrode in which hard carbon (HC) is mixed with graphite (MAGD) is also possible.

[Examples 17 and 18]
The positive electrode A, the negative electrode A, the separator, and the nonaqueous electrolyte solutions B and M were put in a coin can, and the nonaqueous electrolyte storage elements of Examples 17 and 18 were assembled. About the obtained non-aqueous electrolyte storage element, the obtained non-aqueous electrolyte storage element was charged to a final charge voltage of 5.2 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . The results are shown in the table. Even when the cyclic ester GBL was used instead of the cyclic carbonate, a capacity almost equivalent to that of the electrolytic solution containing EC could be obtained.

[Examples 19 and 20]
The positive electrode A, the negative electrode A, the separator, the nonaqueous electrolyte B and QN were put in a coin can, and the nonaqueous electrolyte storage elements of Examples 19 and 20 were assembled. About the obtained non-aqueous electrolyte storage element, the obtained non-aqueous electrolyte storage element was charged to a final charge voltage of 5.2 V at a constant current of 1 mA / cm ² at room temperature (25 ° C.). After the first charge, initial charge / discharge was performed by discharging to 3.0 V at a constant current of 1 mA / cm ² . The results are shown in the table. Even when LiBF ₄ was used as the electrolyte, a capacity almost equivalent to LiPF ₆ could be obtained.

[Example 21]
The positive electrode A, the negative electrode A, the separator, and the non-aqueous electrolyte E were put in a coin can, and the non-aqueous electrolyte storage element of the example was assembled. About the obtained nonaqueous electrolyte solution electrical storage element, it carried out similarly to Example 1, and performed the charging / discharging cycle 100 cycles. FIG. 1 is a graph plotting the discharge capacity of each cycle. The cycle characteristics were improved by adding TPFEPB.

[Example 22]
The positive electrode A, the negative electrode A, the separator, and the non-aqueous electrolyte F were put in a coin can, and the non-aqueous electrolyte storage element of the example was assembled. About the obtained nonaqueous electrolyte solution electrical storage element, it carried out similarly to Example 1, and performed the charging / discharging cycle 100 cycles. FIG. 2 is a plot of the discharge capacity of each cycle. By adding THFIPB, cycle characteristics were improved.

  Table 12 shows details of the nonaqueous electrolyte solution, electrodes, and charge / discharge characteristics in the nonaqueous electrolyte storage batteries of this example and the comparative example.

JP 2003-86245 A JP2013-55285A JP 2009-206071 A JP 2006-286926 A Japanese Patent No. 4503209 Japanese Patent No. 4527605

Journal of The Electrochemical Society, 147 (3) 899-901 (2000)

Claims (10)

A positive electrode including a positive electrode active material capable of inserting or desorbing anions, a negative electrode including a negative electrode active material capable of inserting or desorbing cations, and a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent. Non-aqueous electrolyte storage element,
The non-aqueous solvent contains 85.0-99.9% by weight of chain carbonate and 0.1-15.0% by weight of cyclic carbonate with respect to the total amount of the non-aqueous solvent,
The cyclic carbonate includes at least a fluorinated cyclic carbonate,
The concentration of the electrolyte salt in the non-aqueous electrolyte is 2 mol / L or more.   The nonaqueous electrolyte storage element according to claim 1, wherein a content ratio of the fluorinated cyclic carbonate in the nonaqueous solvent is 0.1 to 10.0% by mass.   The non-aqueous electrolyte storage element according to claim 1, wherein the chain carbonate contains 90% by mass or more of dimethyl carbonate (DMC).   The nonaqueous electrolyte storage element according to claim 1, wherein the concentration of the electrolyte salt in the nonaqueous electrolyte is 3 mol / L or more.   The non-aqueous electrolyte storage element according to claim 1, wherein the non-aqueous electrolyte includes a compound capable of chemically binding an anion containing a halogen atom.   6. The compound capable of chemically binding an anion containing a halogen atom is tris (tetrafluorophenyl) borate (TPFPB) and / or tris (hexafluoroisopropyl) borate (THFIPB). The nonaqueous electrolyte storage element described.   The non-aqueous electrolyte storage element according to claim 1, wherein the negative electrode active material contains at least hard carbon or soft carbon.   The capacity ratio of the said positive electrode active material and the said negative electrode active material is 1: 1.5-1: 4, The nonaqueous electrolyte storage element in any one of Claims 1-7 characterized by the above-mentioned.   The non-aqueous electrolyte storage element according to any one of claims 1 to 8, wherein a maximum voltage during charging and discharging is 4.5 V or more and 6.0 V or less. A lithium ion secondary battery comprising the nonaqueous electrolyte storage element according to claim 1, wherein the electrolyte salt is a lithium salt.

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