WO2020017378A1

WO2020017378A1 - Nonaqueous electrolyte secondary battery

Info

Publication number: WO2020017378A1
Application number: PCT/JP2019/026995
Authority: WO
Inventors: 健二撹上; 真梨恵中西; 雄太野原; 洋平青山
Original assignee: 株式会社Adeka
Priority date: 2018-07-19
Filing date: 2019-07-08
Publication date: 2020-01-23
Also published as: JPWO2020017378A1; KR20210031423A

Abstract

This nonaqueous electrolyte secondary battery includes: a positive electrode; a negative electrode containing silicon atoms; and a nonaqueous electrolyte that contains a lithium salt and a compound represented by general formula (1) (in the formula, R¹-R³ each independently represent a hydrocarbon group having 1-10 carbon atoms, R⁴ represents a n-valent hydrocarbon group having 1-10 carbon atoms, a n-valent group in which a hydrocarbon group having 1-10 carbon atoms is coupled with an oxygen atom or a sulfur atom, or a n-valent heterocyclic group that has 3-6 carbon atoms and that includes an oxygen atom or a sulfur atom, and n represents an integer of 1-6).

Description

Non-aqueous electrolyte secondary battery

The present invention relates to a non-aqueous electrolyte secondary battery using a non-aqueous electrolyte containing a specific component.

Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries are small, lightweight, have a high energy density, and can be repeatedly charged and discharged, so they can be used in portable electronic devices such as portable personal computers, handy video cameras, and information terminals. It is widely used as a power source for equipment. Further, from the viewpoint of environmental problems, electric vehicles using non-aqueous electrolyte secondary batteries and hybrid vehicles using electric power as a part of power have been put into practical use. Therefore, in recent years, further improvements in the performance of secondary batteries have been demanded from the viewpoints of the usable time of portable electronic devices, the cruising distance of automobiles, and their safety.

Charging / discharging capacity is one of the main performances of secondary batteries. In order to improve the charge / discharge capacity, use of a new material for the positive electrode active material and the negative electrode active material has been studied. For example, a material using sulfur as a positive electrode active material has been proposed (for example, Patent Document 1), and a material using silicon, tin, or the like as a negative electrode active material has been proposed (for example, Patent Document 2).

Materials containing silicon, tin, etc., which have been proposed as negative electrode active materials, have larger theoretical capacities than conventionally used carbon materials, but have a large volume change due to charge and discharge, resulting in cracking and pulverization of the electrodes. In addition, separation from the current collector, reaction with the electrolytic solution on the separation surface, and the like occur, and the capacity is reduced, and cycle characteristics (hereinafter, a change in capacity due to charge and discharge is sometimes referred to as cycle characteristics) are not good. Was.

For the purpose of improving the cycle characteristics of a secondary battery using such a negative electrode active material having silicon or tin, an initial charging method (for example, Patent Document 1) and a method of controlling the particle size of the electrode active material (Eg, Patent Document 2) and methods of improving the electrolyte by using an electrolyte additive (eg, Patent Documents 3 to 5) have been proposed. Above all, the technique using an electrolyte additive is an excellent method in that the effect can be easily obtained. In a secondary battery using a non-aqueous electrolyte having an electrolyte additive, a solid electrolyte interface (SEI: Solid Electrolyte Interface) is formed on the surface of the electrode active material during charging and discharging, and a solvent used for the non-aqueous electrolyte is used. Decomposition is suppressed and cycle characteristics are improved. However, the film formed on the electrode active material becomes a resistance component in the charging / discharging process, and the rate characteristic showing high-speed charging / discharging performance is disadvantageous.

JP-A-2005-228289 US20170890505A1 US2011052996A1 US20080996112A1 US20111091768A1

In the nonaqueous electrolyte secondary battery according to the technique disclosed in the above-mentioned prior art document, the rate characteristics were not sufficient.
The present invention has been made in view of the above circumstances, and has as its main object to provide a nonaqueous electrolyte secondary battery having improved cycle characteristics and rate characteristics.

A non-aqueous electrolyte secondary battery that solves the above problems includes a non-aqueous electrolyte including a positive electrode, a negative electrode containing a silicon atom, and a non-aqueous electrolyte containing a compound represented by the general formula (1) and a lithium salt. It is a secondary battery.

(Wherein, R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 10 carbon atoms, R ⁴ is an n-valent hydrocarbon group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms) An n-valent group in which 10 hydrocarbon groups are linked by an oxygen atom or a sulfur atom, or an n-valent heterocyclic group having 3 to 6 carbon atoms containing an oxygen atom or a sulfur atom, wherein n is 1 to 6 Represents an integer.)

According to the present invention, a non-aqueous electrolyte secondary battery having improved cycle characteristics and rate characteristics is provided by using a combination of a negative electrode containing a silicon atom and a non-aqueous electrolyte containing a compound having a specific structure. It becomes possible to do.

FIG. 1 is a longitudinal sectional view schematically showing an example of the structure of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 2 is a schematic diagram showing a basic configuration of a cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 3 is a perspective view showing the internal structure of the cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention as a cross section.

Hereinafter, the nonaqueous electrolyte secondary battery of the present invention will be described in detail based on preferred embodiments.

<Positive electrode>
The positive electrode used in the present invention is not particularly limited, and can be manufactured using a known positive electrode active material and according to a known method. For example, an electrode mixture paste obtained by slurrying a mixture containing a positive electrode active material, a binder and a conductive additive with an organic solvent or water is applied to a current collector and dried to form an electrode mixture on the current collector. A positive electrode having a layer formed thereon can be manufactured.

(Positive electrode active material)
Known positive electrode active materials include, for example, lithium transition metal composite oxides, lithium-containing transition metal phosphate compounds, lithium-containing silicate compounds, and lithium-containing transition metal sulfate compounds. The positive electrode active material may be used alone or in combination of two or more.

As the transition metal of the lithium transition metal composite oxide, vanadium, titanium, chromium, manganese, iron, cobalt, nickel, copper, and the like are preferable. Specific examples of the lithium transition metal composite oxide include a lithium cobalt composite oxide such as LiCoO ₂ , a lithium nickel composite oxide such as LiNiO ₂ , and a lithium manganese composite oxide such as LiMnO ₂ , LiMn ₂ O ₄ , and Li ₂ MnO _3. Aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, etc. And those substituted with other metals. Examples of the lithium transition metal composite oxide in which part of the main transition metal atom is substituted with another metal include, for example, Li _1.1 Mn _1.8 Mg _0.1 O ₄ and Li _1.1 Mn _1.85. Al _0.05 O ₄ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , LiNi _0.5 Mn _0.5 O ₂ , LiNi _{0 .80} Co _0.17 Al _0.03 O ₂ , LiNi _0.80 Co _0.15 Al _0.05 O ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiNi _0.6 Co _{0. 2} Mn _0.2 O ₂ , LiMn _1.8 Al _0.2 O ₄ , LiNi _0.5 Mn _1.5 O ₄ , Li ₂ MnO ₃ —LiMO ₂ (M = Co, Ni, Mn) and the like. .

As the transition metal of the lithium-containing transition metal phosphate compound, vanadium, titanium, manganese, iron, cobalt, nickel and the like are preferable. Specific examples of the lithium-containing transition metal phosphate compound include iron phosphate compounds such as LiFePO ₄ and LiM _x Fe _1-x PO ₄ (M = Co, Ni, Mn), and cobalt phosphate compounds such as LiCoPO ₄ . , And part of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds, aluminum, titanium, vanadium, chromium, manganese, iron, cobalt, lithium, nickel, copper, zinc, magnesium, gallium, zirconium, Examples thereof include those substituted with other metals such as niobium, and vanadium phosphate compounds such as Li ₃ V ₂ (PO ₄ ) ₃ .

Examples of the lithium-containing silicate compound include Li ₂ FeSiO _{4 and the} like, and examples of the lithium-containing transition metal sulfate compound include LiFeSO ₄ and LiFeSO ₄ F.

Further, sulfur, a sulfur-carbon composite, and a sulfur-modified organic compound can be used as the positive electrode active material.
As the sulfur, various forms such as powdered sulfur, insoluble sulfur, precipitated sulfur, and colloidal sulfur can be used, but powdered sulfur is preferable in consideration of uniformly dispersing the raw material compound.

The sulfur-carbon composite is obtained by mechanically complexing sulfur and carbon, or containing sulfur in the pores of porous carbon, and is capable of absorbing and releasing lithium ions. A material that can be used as an electrode active material for a battery. The sulfur content of the sulfur-carbon composite in which sulfur is supported in the pores of the porous carbon is such that when the content is too small, the charge / discharge capacity does not increase, and when the content is too large, the electron conductivity decreases. It is preferably from 90% by mass to 90% by mass, more preferably from 30% by mass to 70% by mass. Examples of the porous carbon include graphite, carbon, carbon black, Ketjen black, acetylene black, graphite, carbon fiber, activated carbon, and mesoporous carbon produced by a known production method. The shape of the porous carbon may be spherical, fibrous, hollow, cylindrical, or amorphous. Two or more of these can be used. Among the porous carbons, Ketjen black, activated carbon, and mesoporous carbon are preferable because of their large surface area and high electron conductivity. The method for forming a composite of sulfur and porous carbon is not particularly limited, and examples thereof include a method of mechanically mixing with various mills, a liquid phase and / or a gas phase method, or a method combining these methods. As a method of mechanically compounding, for example, a ball mill such as a planetary ball mill, a rolling ball mill, a vibrating ball mill, a vertical roller mill such as a ring roller mill, a high-speed rotation mill such as a hammer mill and a cage mill, and an air current such as a jet mill. A type mill and the like can be mentioned.

The sulfur-modified organic compound is an organic compound containing at least 25% by mass or more, preferably 30% by mass or more of sulfur and capable of occluding and releasing lithium ions and usable as an electrode active material of a secondary battery. Say. Sulfur-modified organic compounds include sulfur and organic compounds such as polyacrylonitrile compounds, elastomer compounds, pitch compounds, polynuclear aromatic ring compounds, aliphatic hydrocarbon oxides, polyether compounds, polyacene compounds, polyamide compounds, and hexachlorobutadiene compounds. It can be manufactured by mixing and heat denaturing at 250 ° C. to 600 ° C. in a non-oxidizing gas atmosphere. The non-oxidizing atmosphere is an atmosphere having an oxygen concentration of less than 5% by volume, preferably less than 2% by volume, more preferably an atmosphere containing substantially no oxygen, that is, an inert gas atmosphere such as nitrogen, helium, or argon, It is a sulfur gas atmosphere.

The average particle diameter (D50) of the positive electrode active material in the present invention is preferably 0.5 μm to 100 μm, and more preferably 1 μm to 50 μm, from the viewpoint of obtaining a uniform and smooth electrode mixture layer and the handleability in the slurrying step. More preferably, it is more preferably from 1 μm to 30 μm. In the present invention, the average particle diameter (D50) refers to a 50% particle diameter measured by a laser diffraction light scattering method. The particle diameter is a volume-based diameter, and the diameter of the secondary particles is measured by the laser diffraction light scattering method.

The positive electrode active material can have a desired particle size by a method such as pulverization. The pulverization may be dry pulverization performed in a gas or wet pulverization performed in a liquid such as water. Examples of the industrial pulverization method include a ball mill, a roller mill, a turbo mill, a jet mill, a cyclone mill, a hammer mill, a pin mill, a rotary mill, a vibration mill, a planetary mill, an attritor, and a bead mill.

(binder)
Known binders can be used as the binder. Specifically, for example, styrene-butadiene rubber, butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, styrene-isoprene rubber, fluororubber, polyethylene, polypropylene, polyacrylamide, polyamide, polyamideimide, polyimide, polyacrylonitrile , Polyurethane, polyvinylidene fluoride, polytetrafluoroethylene, styrene-acrylate copolymer, ethylene-vinyl alcohol copolymer, polymethyl methacrylate, polyacrylate, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl ether, polychloride Vinyl, acrylic acid, polyacrylic acid, methyl cellulose, carboxymethyl cellulose, carboxymethyl cellulose Sodium, cellulose nanofibers, and starch. Only one binder may be used, or two or more binders may be used in combination. The content of the binder is preferably from 1 to 30 parts by mass, more preferably from 1 to 20 parts by mass, per 100 parts by mass of the positive electrode active material.

(Conduction aid)
As the conductive assistant, those known as conductive assistants for electrodes can be used. Specifically, for example, natural graphite, artificial graphite, coal tar pitch, carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, roller black, disk black, carbon nanotube, gas phase Carbon materials such as carbon fiber (Vapor Carbon Carbon Fiber: VGCF), graphene, fullerene, and needle coke; metal powders such as aluminum powder, nickel powder, and titanium powder; conductive metal oxides such as zinc oxide and titanium oxide; Sulfides such as La ₂ S ₃ , Sm ₂ S ₃ , Ce ₂ S ₃ , and TiS ₂ are exemplified. The particle size of the conductive additive is preferably from 0.0001 μm to 100 μm, more preferably from 0.01 μm to 50 μm. The content of the conductive additive is usually 0.1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass with respect to 100 parts by mass of the electrode active material.

(solvent)
Examples of the solvent for preparing the electrode mixture paste include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, acetonitrile, and acetonitrile. Pionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, dioxane, 1,3-dioxolane, nitromethane, N-methylpyrrolidone, N, N-dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, polyethylene oxide, tetrahydrofuran, dimethyl sulfoxide, sulfolane, γ-butyrolactone, water, alcohol Etc. The. The amount of the solvent used may be adjusted according to the method selected when coating the slurry.For example, in the case of application by the doctor blade method, the total amount of the positive electrode active material, the binder and the conductive additive is 100 parts by mass. On the other hand, the amount is preferably from 15 to 300 parts by mass, more preferably from 30 to 200 parts by mass.

The electrode mixture paste contains, in addition to the above components, other components such as a viscosity adjuster, a reinforcing material, an antioxidant, a pH adjuster, and a dispersant, in a range that does not impair the effects of the present invention. It does not matter. As these other components, known components can be used in known mixing ratios.

(Electrode mixture paste manufacturing process)
In the production of the electrode mixture paste, when dispersing or dissolving the positive electrode active material, the binder and the conductive auxiliary in a solvent, all can be added to the solvent at once and subjected to dispersion treatment, and separately added and dispersed. You can also. It is preferable to sequentially add a binder, a conductive auxiliary agent, and an active material to a solvent in the order of the dispersion treatment, since these can be uniformly dispersed in the solvent. When the electrode mixture paste contains other components, the other components can be added at once and subjected to a dispersion treatment. However, it is preferable to perform the dispersion treatment every time one kind is added.

The method of the dispersion treatment is not particularly limited, but as an industrial method, for example, a normal ball mill, a sand mill, a bead mill, a cyclone mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a rotation / revolution mixer, A planetary mixer, a fill mix, a jet paster, or the like can be used.

(Current collector)
As the current collector, a conductive material such as titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, stainless steel, nickel-plated steel, and carbon is used. Examples of the shape of the current collector include a foil shape, a plate shape, a net shape, a foamed shape, and a nonwoven fabric shape. The current collector may be either porous or non-porous. In addition, these conductive materials may be subjected to a surface treatment in order to improve adhesion and electrical characteristics. Among these conductive materials, aluminum is preferred from the viewpoint of conductivity and price, and aluminum foil is particularly preferred. The thickness of the current collector is not particularly limited, but is usually 5 to 30 μm.

(Positive electrode manufacturing process)
The method of applying the electrode mixture paste to the current collector is not particularly limited. For example, a die coater method, a comma coater method, a curtain coater method, a spray coater method, a gravure coater method, a flexo coater method, a knife coater method, a doctor coater method Each method such as a blade method, a reverse roll method, a brush coating method, and a dip method can be used. A die coater method, a knife coater method, a doctor blade method, and a comma coater method are preferable in that a good coating layer surface state can be obtained in accordance with the viscosity and drying properties of the electrode mixture paste.

塗布 The application of the electrode mixture paste to the current collector may be performed on only one side of the current collector, or may be performed on both sides. When applied to both surfaces of the current collector, the current collector can be applied one by one successively, or both surfaces can be applied simultaneously. Further, it can be applied continuously to the surface of the current collector, can be applied intermittently, or can be applied in a stripe shape. The thickness, length and width of the coating layer can be appropriately determined according to the size of the battery and the like.

方法 The method of drying the electrode mixture paste applied on the current collector is not particularly limited, and a known method can be used. Examples of the drying method include drying with warm air, hot air, low-humidity air, vacuum drying, standing in a heating furnace or the like, and drying by irradiating far-infrared rays, infrared rays, electron beams, or the like. These can be implemented in combination. The temperature at the time of heating is, for example, generally about 50 ° C. to 180 ° C., but the conditions such as the temperature can be appropriately set according to the application amount of the slurry composition, the boiling point of the solvent used, and the like. . By this drying, volatile components such as a solvent are volatilized from the coating film of the electrode mixture paste composition, and an electrode mixture layer is formed on the current collector.

(4) When a lithium-free material such as sulfur, a sulfur-carbon composite, or a sulfur-modified organic compound is used as the positive electrode active material, lithium can be doped in advance. The method of doping the material may be a known method. For example, assembling a half-cell using metallic lithium as the counter electrode and inserting lithium by an electrolytic doping method of electrochemically doping lithium, or attaching a metallic lithium foil to the electrode and leaving it in the electrolytic solution There is a method of inserting lithium by a sticking doping method of doping using diffusion of lithium to the electrode, a mechanical doping method of mechanically colliding an active material with lithium metal and inserting lithium, and the like. It is not limited.

<Negative electrode>
The negative electrode containing a silicon atom used in the present invention is not particularly limited, and can be produced according to a known method using a negative electrode active material containing a silicon atom. For example, a negative electrode active material containing a silicon atom, an electrode mixture paste obtained by slurrying a composition containing a binder and a conductive auxiliary agent with an organic solvent or water, by coating and drying the current collector, the current collector A negative electrode having an electrode mixture layer formed thereon can be manufactured.

(Negative electrode active material)
Examples of the negative electrode active material containing a silicon atom include simple substance silicon, silicon nitride, an alloy containing silicon, SiO, SiO _x , SiO ₂ , and a Si-containing material coated with a carbon material, or a mixture of a Si-containing material and carbon. A composite material of a Si-containing material and a carbon material in which the material is composited is exemplified. Examples of the Si-containing material include simple silicon, silicon nitride, an alloy containing silicon, SiO, SiO _x , and SiO. The negative electrode active material containing a silicon atom may be carbon-coated. As the negative electrode active material containing a silicon atom, only one type may be used, or two or more types may be used in combination.

The silicon nitride (Si ₃ N ₄ ) may have an α-phase or β-phase crystal phase.
As the alloy containing silicon, for example, as the second constituent element other than silicon, lithium, aluminum, tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, and antimony And at least one of the group consisting of chromium.

_X of the SiO _x is usually 0.01 or more and less than 2. By setting x to a certain value or more, it is possible to suppress a volume change at the time of charging and discharging that may occur due to a high Si ratio, and to prevent a decrease in cycle characteristics due to the volume change. By setting x to be equal to or less than a certain value, the decrease in capacity can be suppressed by increasing the Si ratio. From these points, x is preferably 0.5 to 1.6, and more preferably 0.8 to 1.3. SiO _x can be formed using, for example, a reaction between Si and SiO ₂ or a disproportionation reaction of silicon monoxide (SiO). Specifically, for example, a SiO, heat treated in the presence of polymers such as polyvinyl alcohol, by forming a Si and SiO _2, can be prepared SiO _x, it is not limited thereto . The heat treatment can be performed, for example, at a temperature of 900 ° C. or higher, preferably 1000 ° C. or higher in an atmosphere containing an organic substance gas and / or steam after pulverizing and mixing SiO and a polymer.

The method of compounding when producing a compound of the Si-containing material and the carbon material is not particularly limited.For example, benzene, toluene, xylene, alkane, or the like is decomposed in a gas phase with a carbon source, and CVD method of chemical vapor deposition, method of applying thermoplastic resin such as pitch, tar or furfuryl alcohol on the surface of particles and then firing, or applying mechanical energy between particles and carbon material to composite A method using a mechanochemical reaction that forms Among them, it is preferable to use the CVD method because the carbon material can be uniformly coated.

Regardless of whether the negative electrode is composited with a carbon material or not, it is particularly preferable that the negative electrode contains silicon or SiO _x (X = 0.5 to 1.6) because of its excellent charge / discharge capacity and cycle characteristics. preferable.

The negative electrode containing a silicon atom used in the present invention may further contain a carbon material as a negative electrode active material. As the carbon material that can be contained as the negative electrode active material, a known material from which lithium ions can be inserted and removed can be used. Examples of the carbon material that can be used as the negative electrode active material include natural graphite, artificial graphite, non-graphitizable carbon, graphitizable carbon, and the like. The negative electrode containing a silicon atom used in the present invention may further contain a lithium-transition metal composite oxide (eg, Li ₄ Ti ₅ O ₁₂ ), tin, or the like as a negative electrode active material.

The content of silicon atoms in the negative electrode is not particularly limited, but a small content has a small effect of improving capacity, and a large content increases the rate of change in volume of the negative electrode active material due to charge and discharge and increases the durability of the electrode. And the cycle characteristics of the non-aqueous electrolyte secondary battery decrease. Therefore, the content of silicon atoms in the electrode mixture layer is preferably 1% by mass to 98% by mass, more preferably 2% by mass to 95% by mass, still more preferably 5% by mass to 90% by mass, and 5% by mass. The content is more preferably from 80 to 80% by mass, and most preferably from 5 to 70% by mass. This amount is based on silicon atoms and can be measured by, for example, an inductively coupled plasma emission spectrometer (ICP-AES), an electron beam microanalyzer (EPMA), an energy dispersive X-ray analyzer (EDX), or the like.

形状 The shape of the negative electrode active material is not particularly limited, but may be, for example, spherical, polyhedral, fibrous, rod-like, plate-like, scale-like, or amorphous, and may be hollow. Among these shapes, a spherical or polyhedral shape is preferable because the electrode mixture layer is formed uniformly.

If the particle diameter of the negative electrode active material containing silicon atoms is too large, a uniform and smooth electrode mixture layer may not be obtained, and if the particle diameter is too small, the handling property in the slurrying step is reduced. Therefore, the average particle diameter (D50) of the silicon-containing negative electrode active material in the present invention is preferably 0.01 μm to 50 μm, more preferably 0.05 μm to 30 μm, and further preferably 0.1 μm to 20 μm. When the negative electrode active material contains a carbon material that does not contain silicon, the average particle diameter of the negative electrode active material containing the carbon material is in the same range as the preferable range described above for the average particle diameter of the negative electrode active material containing silicon atoms. It may be.

The negative electrode active material can have a desired particle size by a method such as pulverization. The pulverization may be dry pulverization performed in a gas or wet pulverization performed in a liquid such as water. Examples of the industrial pulverization method include a ball mill, a roller mill, a turbo mill, a jet mill, a cyclone mill, a hammer mill, a pin mill, a rotary mill, a vibration mill, a planetary mill, an attritor, and a bead mill. When a plurality of types of negative electrode active materials are used, the negative electrode active materials may be pulverized for each material and then mixed, or may be mixed and pulverized.

(binder)
Known binders can be used as the binder. Specific examples of the binder include, for example, those similar to the binder used for the positive electrode. Only one binder may be used, or two or more binders may be used in combination. The content of the binder is preferably from 1 to 30 parts by mass, more preferably from 1 to 20 parts by mass, per 100 parts by mass of the negative electrode active material.

(Conduction aid)
As the conductive assistant, those known as conductive assistants for electrodes can be used. Specifically, the same as the conductive additive used for the positive electrode can be used.
The particle size of the conductive additive is preferably from 0.0001 μm to 100 μm, more preferably from 0.01 μm to 50 μm.
The content of the conductive additive is usually 0 to 50 parts by mass, preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the negative electrode active material.

(solvent)
Examples of the solvent for preparing the electrode mixture paste include the same solvents as those used for preparing the positive electrode mixture paste. The amount of the solvent used can be adjusted according to the method selected when coating the slurry. For example, in the case of application by the doctor blade method, the total amount of the negative electrode active material, the binder and the conductive auxiliary agent is 100 parts by mass. Is preferably 15 to 300 parts by mass, more preferably 30 to 200 parts by mass.

In the electrode mixture paste, in addition to the above components, within a range not impairing the effects of the present invention, for example, a viscosity modifier, a reinforcing material, an antioxidant, a pH adjuster, and other components such as a dispersant are contained. No problem. As these other components, known components can be used in known mixing ratios.

(Electrode mixture paste manufacturing process)
Except for using the negative electrode active material instead of the positive electrode active material in the production of the electrode mixture paste, it can be blended, dispersed and produced in the same process as the production process of the positive electrode mixture paste.

(Current collector)
As the current collector, a conductive material such as titanium, a titanium alloy, aluminum, an aluminum alloy, copper, nickel, stainless steel, nickel-plated steel, and carbon is used. Examples of the shape of the current collector include a foil shape, a plate shape, a net shape, a foamed shape, and a nonwoven fabric shape. The current collector may be either porous or non-porous. In addition, these conductive materials may be subjected to a surface treatment in order to improve adhesion and electrical characteristics. Among these conductive materials, copper is preferred from the viewpoints of stability at negative electrode potential, conductivity, and price, and copper foil is particularly preferred. The thickness of the current collector is not particularly limited, but is usually 5 to 30 μm.

負極 The negative electrode used in the present invention may be used after being doped with lithium in advance. The doping method may be in accordance with a known method. For example, assembling a half-cell using metallic lithium as the counter electrode and inserting lithium by electrolytic doping method of electrochemically doping lithium, or attaching a metallic lithium foil to the electrode and leaving it in the electrolytic solution Doping using the diffusion of lithium into the electrode, a method of inserting lithium by a sticking doping method, a mechanical doping method of mechanically colliding an active material with lithium metal and inserting lithium, and the like. However, the present invention is not limited to this.

負極 The negative electrode active material or the negative electrode used in the present invention may have a film formed on its surface with a material having a siloxane bond. A material having a siloxane bond and a method of forming a film may be in accordance with a known method.

<Non-aqueous electrolyte>
The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery of the present invention contains a compound represented by the following general formula (1).

(Wherein, R ¹ to R ³ each independently represent a hydrocarbon group having 1 to 10 carbon atoms, R ⁴ is an n-valent hydrocarbon group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms) An n-valent group in which 10 hydrocarbon groups are linked by an oxygen atom or a sulfur atom, or an n-valent heterocyclic group having 3 to 6 carbon atoms containing an oxygen atom or a sulfur atom, wherein n is 1 to 6 Represents an integer.)
n number R ¹ present may or may not be the same as each other. The same applies to R ² and R ³ each having n pieces.

When the nonaqueous electrolyte contains the compound represented by the general formula (1), the cycle characteristics and the rate characteristics of the nonaqueous electrolyte secondary battery using the negative electrode containing a silicon atom are improved. Can be.

Examples of the hydrocarbon group having 1 to 10 carbon atoms represented by R ¹ to R ³ in the compound represented by the general formula (1) include, for example, a saturated aliphatic hydrocarbon group and an unsaturated aliphatic hydrocarbon group. And aromatic hydrocarbon groups. Specifically, methyl, ethyl, propyl, i-propyl, butyl, 2-butyl, i-butyl, t-butyl, pentyl, 2-pentyl, 3-pentyl, i-pentyl, hexyl, 2-hexyl, 3-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, nonyl, decyl, cyclopentyl, cyclohexyl, methylcyclohexyl, norbornane Group, saturated aliphatic hydrocarbon group such as adamantyl group, unsaturated aliphatic group such as vinyl group, allyl group, butenyl group, pentenyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, cyclooctenyl group, norbornene group, etc. Hydrocarbon group, phenyl group, methylphenyl group, ethylphenyl group, t-butylphenyl group, phenylmethyl group Phenylethyl group, and aromatic hydrocarbon groups such as a naphthyl group. The saturated aliphatic hydrocarbon group and the unsaturated aliphatic hydrocarbon group may have a linear structure or a branched structure. Among them, the hydrocarbon group having 1 to 10 carbon atoms representing R ¹ to R ³ is preferably a hydrocarbon group having 1 to 4 carbon atoms because both the cycle characteristics and the rate characteristics are improved and the production process is simple. An aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 10 carbon atoms is preferable, a methyl group, an ethyl group, a butyl group, a vinyl group or a phenyl group is more preferable, and a methyl group, an ethyl group, a vinyl group or a phenyl group is more preferable. Even more preferred is a methyl group.

The content of the compound represented by the general formula (1) is preferably 0.01% by mass to 20% by mass, more preferably 0.05% by mass to 10% by mass, and more preferably 0.1% by mass in the nonaqueous electrolyte. -7% by mass is more preferable, and 0.1-5% by mass is most preferable. When the content is 0.01% by mass or more, the cycle characteristics and the rate characteristics are sufficiently improved. When the content is 20% by mass or less, the effect of improving the cycle characteristics and the rate characteristics commensurate with the added amount. There is expected.

Among the compounds represented by the general formula (1), R ¹ to R ³ are saturated hydrocarbon groups, and R ⁴ is a group in which two methylene groups are connected by a sulfur atom. No. 1-1 to No. 1-29, but is not limited thereto. Compound No. A notation such as 1-28 indicates that the position of the substituent is arbitrary.

In the compound represented by the general formula (1), any ^{one of} n R ¹ to R ³ is an unsaturated hydrocarbon group, and R ⁴ is a group in which two methylene groups are connected by a sulfur atom. As one compound, for example, the following compound No. 1-30 to No. 1-53, but is not limited thereto.

In the compound represented by the general formula (1), any ^{one of} n R ¹ to R ³ is an aromatic hydrocarbon group, and R ⁴ is a group in which two methylene groups are connected by a sulfur atom. As a certain compound, for example, the following compound No. 1-54 to No. 60, but is not limited thereto.

R ^{4 in the} general formula (1) is an n-valent hydrocarbon group having 1 to 10 carbon atoms, an n-valent group in which a hydrocarbon group having 1 to 10 carbon atoms is connected by an oxygen atom or a sulfur atom, or Represents an n-valent heterocyclic group containing an oxygen atom or a sulfur atom, and n represents an integer of 1 to 6. When R ⁴ is an n-valent hydrocarbon group having 1 to 10 carbon atoms, the compound represented by the general formula (1) is a compound represented by the following general formula: This corresponds to a compound substituted with a group represented by the formula (1a).

(In the formula, R ¹ to R ³ have the same meaning as in the general formula (1), and * represents a binding site.)

Examples of the hydrocarbons having 1 to 10 carbon atoms in which n hydrogen atoms are substituted by the general formula (1a) include saturated aliphatic hydrocarbons, unsaturated aliphatic hydrocarbons, and aromatic hydrocarbons. Specifically, for example, methane, ethane, propane, n-butane, 2-methylpropane, n-pentane, n-hexane, cyclohexane, methylcyclohexane, n-heptane, n-octane, n-nonane, n-decane And saturated aliphatic hydrocarbons such as n-adamantane, ethene, ethyne, propene, propyne, 1-butene, 2-butene, 1,3-butadiene, 1-pentene, 2-pentene, 1,3-pentadiene, 1- Hexene, 3-hexene, 1,3,5-hexatriene, cyclohexene, 1-heptene, 1-octene, 3-octene, 1,3,5,7-octatetraene, 1-nonene, 1-decene and the like Aroma of unsaturated aliphatic hydrocarbons, benzene, phenol, methylbenzene, dimethylbenzene, ethylbenzene, butylbenzene, naphthalene, etc. Group hydrocarbons.

When R ^{4 in the} general formula (1) is an n-valent group in which a hydrocarbon group having 1 to 10 carbon atoms is connected by an oxygen atom or a sulfur atom, the compound represented by the general formula (1) is The compound corresponds to a compound in which a hydrocarbon group having 1 to 10 carbon atoms is connected by an oxygen atom or a sulfur atom, wherein n hydrogen atoms are substituted by a group represented by the general formula (1a).

Examples of the compound in which a hydrocarbon group having 1 to 10 carbon atoms is linked by an oxygen atom or a sulfur atom include a compound in which a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group is linked by an oxygen atom or a sulfur atom. No. The linked saturated aliphatic hydrocarbon groups or unsaturated aliphatic hydrocarbon groups may be the same or different. The saturated aliphatic hydrocarbon group or unsaturated aliphatic hydrocarbon group is the same as the saturated aliphatic hydrocarbon group or unsaturated aliphatic hydrocarbon group represented by R ¹ to R ³ in the general formula (1). No. Note that the expression “connected by an oxygen atom or a sulfur atom” includes not only a case where the connection is made with one oxygen atom or a sulfur atom but also a case where the connection is made with two or more oxygen atoms or oxygen atoms. The latter case includes, for example, a case where they are linked by -SS-, and a case where they are represented by -S-RS- or the like (R is an alkylene group having 1 or 2 carbon atoms). .

When R ^{4 in the} general formula (1) is an n-valent heterocyclic group having 3 to 6 carbon atoms containing an oxygen atom or a sulfur atom, the compound represented by the general formula (1) is a compound having 3 to 6 carbon atoms. This corresponds to a compound in which n hydrogen atoms of the heterocyclic ring 6 are substituted with a group represented by the general formula (1a). Examples of the heterocyclic ring having 3 to 6 carbon atoms including an oxygen atom include 1,3-propylene oxide, tetrahydrofuran, tetrahydropyran, and furan. Examples of the heterocyclic ring having 3 to 6 carbon atoms including a sulfur atom include trimethylene sulfide, tetrahydrothiophene, tetrahydrothiopyran, thiophene and the like.

As a compound in which two hydrogen atoms of a saturated hydrocarbon are substituted with a group represented by the general formula (1a) and R ¹ to R ³ are methyl groups, for example, the following compound No. 1a-1 to No. 1 1a-28, but not limited thereto.

As a compound in which two hydrogen atoms of an unsaturated hydrocarbon are substituted with a group represented by the general formula (1a), and R ¹ to R ³ are methyl groups, for example, the following compound No. 1a-29 to No. 1 1a-58, but not limited thereto.

As a compound in which two hydrogen atoms of an aromatic hydrocarbon are substituted by a group represented by the general formula (1a), and R ¹ to R ³ are methyl groups, for example, the following compound No. 1a-59 to No. 1 1a-66, but is not limited thereto. No. A bond extending over a plurality of rings described in 1a-66 means that a bond can be bonded to any position of these rings.

Two hydrogen atoms of a compound in which a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group is linked by a sulfur atom are substituted with a group represented by the general formula (1a), and R ¹ to R ³ are As the compound that is a methyl group, for example, the following compound No. 1a-67 to 1a-84. In addition, compounds in which some or all of the sulfur atoms of these compounds are replaced with oxygen atoms are also examples (eg, Nos. 1a-85 to 1a-86). However, the present invention is not limited to these.

A compound in which two hydrogen atoms of a heterocyclic group having 3 to 6 carbon atoms including an oxygen atom or a sulfur atom are substituted with a group represented by the general formula (1a), and R ¹ to R ³ are methyl groups. For example, the following compound No. 1a-87 to No. 1 1a-94, but is not limited thereto.

R ⁴ is preferably an n-valent aliphatic hydrocarbon group having 2 to 10 carbon atoms, because of improved cycle characteristics and rate characteristics, a simple production process, and easy availability. Preferred are an n-valent group in which 1 to 10 hydrocarbon groups are connected by a sulfur atom, and an n-valent heterocyclic group having 3 to 6 carbon atoms containing a sulfur atom. As the aliphatic hydrocarbon group represented by R ⁴ , an aliphatic hydrocarbon group having 2 to 6 carbon atoms is more preferable, and an unsaturated aliphatic hydrocarbon group having 2 to 4 carbon atoms is most preferable. As the n-valent group in which a hydrocarbon group having 1 to 10 carbon atoms represented by R ⁴ is linked by a sulfur atom, an aliphatic hydrocarbon group having 1 to 6 carbon atoms is linked to a sulfur atom A group is preferable, and a group in which an aliphatic hydrocarbon group having 1 to 4 carbon atoms is connected to one sulfur atom or the above-mentioned —S—R—S— group is particularly preferable. As the sulfur-containing n-valent heterocyclic group having 3 to 6 carbon atoms represented by R ⁴ , an aromatic heterocyclic ring having 3 to 8 carbon atoms including a sulfur atom is particularly preferable, and thiophene is most preferable. Further, R ⁴ is preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms in addition to the above groups. n is preferably 2 to 6, more preferably 2 to 4, and most preferably 2, because the cycle characteristics and rate characteristics of the nonaqueous electrolyte secondary battery are good.

化合物 As the compound represented by the general formula (1), the compound No. 1 can be used because the cycle characteristics and the rate characteristics are both improved and the production process is simple. 1-1, No. 1a-1, No. 1; 1a-2, No. 1 1a-29, no. 1a-35, no. 1a-59, no. 1a-68, no. 1a-77, no. 1a-82 and No. 1 No. 1a-92 is preferable. 1-1, No. 1a-1, No. 1; 1a-29, no. Nos. 1a-82 and No. 1 1a-94 is more preferred.

非 The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery of the present invention contains a lithium salt. As the non-aqueous electrolyte, a liquid electrolyte obtained by dissolving a lithium salt in a solvent, a polymer gel obtained by dissolving or dispersing a lithium salt in a polymer gel gelled with a polymer compound dissolved in a solvent, A pure polymer electrolyte obtained by using a polymer compound as a dispersion medium and dissolving or dispersing a lithium salt can be used.

The lithium salt used for the liquid electrolyte and the polymer gel electrolyte is not particularly limited, and conventionally known lithium salts, for example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (SO ₂ F) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiB (CF ₃ SO ₃ ) ₄ , LiB (C ₂ _{_{_{O 4) 2, LiBF 2 (}}} C 2 O 4), LiSbF 6, LiSiF 5, LiSCN, LiClO 4, LiCl, LiF, LiBr, LiI, LiAlF 4, LiAlCl 4, LiPO 2 F 2, and derivatives of these Among _{_{_{them, LiPF 6, LiBF 4, LiClO}}} 4, LiCF 3 SO 3, LiN (C _{_{_{_{3 SO 2) 2, LiN (}}}} C 2 F 5 SO 2) 2, LiN (SO 2 F) 2, LiPO 2 F 2, LiC (CF 3 SO 2) 3 and derivatives LiCF ₃ SO ₃ and LiC (CF ₃ Derivatives of SO ₂ ) ₃ are preferred. Only one lithium salt may be used, or two or more lithium salts may be used in combination.

Examples of the lithium salt used for the pure polymer electrolyte include LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (SO ₂ F) ₂ , and LiC (CF ₃ SO ₂ ) _3. , LiB (CF ₃ SO ₃ ) ₄ , LiB (C ₂ O ₄ ) _{2 and the} like.

If the concentration of the lithium salt in the nonaqueous electrolyte is too low, a sufficient current density may not be obtained, and if the concentration is too high, the stability of the liquid nonaqueous electrolyte may be impaired. L is preferable, and 0.8 to 1.8 mol / L is more preferable.

として As the organic solvent used for the liquid electrolyte, an organic solvent usually used for a non-aqueous electrolyte of a non-aqueous electrolyte secondary battery can be used. Examples of the organic solvent usually used for the non-aqueous electrolyte of the non-aqueous electrolyte secondary battery include, for example, a saturated cyclic carbonate compound, a saturated cyclic ester compound, a sulfoxide compound, a sulfone compound, an amide compound, a saturated chain carbonate compound, and a chain ether. Compounds, cyclic ether compounds, saturated chain ester compounds and the like. Only one organic solvent may be used, or two or more organic solvents may be used in combination.

Among the organic solvents, the saturated cyclic carbonate compound, the saturated cyclic ester compound, the sulfoxide compound, the sulfone compound and the amide compound have a high relative dielectric constant, and thus play a role of increasing the dielectric constant of the liquid composition, and in particular, the saturated cyclic carbonate compound. Is preferred.

Examples of the saturated cyclic carbonate compound include ethylene carbonate, 1,2-propylene carbonate, 1,3-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 1,1-dimethylethylene carbonate and the like. Can be
Examples of the saturated cyclic ester compound include γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-hexanolactone, δ-octanolactone, and the like.
Examples of the sulfoxide compound include dimethyl sulfoxide, diethyl sulfoxide, dipropyl sulfoxide, diphenyl sulfoxide, and thiophene.
Examples of the sulfone compound include dimethyl sulfone, diethyl sulfone, dipropyl sulfone, diphenyl sulfone, sulfolane (also referred to as tetramethylene sulfone), 3-methyl sulfolane, 3,4-dimethyl sulfolane, 3,4-diphenyl sulfolane, sulfolene, Examples include 3-methylsulfolene, 3-ethylsulfolene, and 3-bromomethylsulfolene. Sulfolane and tetramethylsulfolane are preferred.
Amide compounds include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.

Among the organic solvents, the saturated chain carbonate compound, the chain ether compound, the cyclic ether compound and the saturated chain ester compound can lower the viscosity of the liquid composition and increase the mobility of electrolyte ions. For example, the battery characteristics such as the output density can be improved. Further, since the viscosity is low, the performance of the non-aqueous electrolyte at a low temperature can be enhanced, and a saturated chain carbonate compound is particularly preferable.
Examples of the saturated chain carbonate compound include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl butyl carbonate, methyl-t-butyl carbonate, diisopropyl carbonate, t-butyl propyl carbonate and the like.
Examples of the chain ether compound or cyclic ether compound include dimethoxyethane, ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolan, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, and 1,2-bis (ethoxycarbonyl). Oxy) ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, propylene glycol bis (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis (tri Fluorooxo) ether and the like, and among these, dioxolan is preferable.
As the saturated chain ester compound, a monoester compound and a diester compound having a total of 2 to 8 carbon atoms in the molecule are preferable, and specific compounds include, for example, methyl formate, ethyl formate, methyl acetate, acetic acid and the like. Ethyl, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, methyl malonate, ethyl malonate, methyl succinate, ethyl succinate, Methyl 3-methoxypropionate, ethyl 3-methoxypropionate, ethylene glycol diacetyl, propylene glycol diacetyl and the like, among which methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, propyl acetate, isobutyl acetate, butyl acetate ,Professional Methyl propionic acid, and ethyl propionate are preferred.

In addition, as the organic solvent used for preparing the liquid electrolyte, for example, acetonitrile, propionitrile, nitromethane, derivatives thereof, and various ionic liquids can be used.

Examples of the polymer used for the polymer gel electrolyte include polyethylene oxide, polypropylene oxide, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, polyethylene, polyvinylidene fluoride, and polyhexafluoropropylene. Examples of the polymer used for the pure polymer electrolyte include polyethylene oxide, polypropylene oxide, and polystyrene sulfonic acid.
There is no particular limitation on the mixing ratio and the method of compounding in the polymer gel electrolyte or the pure polymer electrolyte, and a compounding ratio and a known compounding method known in the art can be adopted.

非 The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery of the present invention may further contain a compound represented by the general formula (2) because battery characteristics such as cycle characteristics and safety are improved.

(Wherein, R ⁵ to R ⁹ each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a heterocyclic group having 4 to 6 carbon atoms, and at least one hydrogen atom Represents a hydrocarbon group having 1 to 6 carbon atoms substituted by a fluorine atom, or a heterocyclic group having 4 to 6 carbon atoms substituted by one or more hydrogen atoms by a fluorine atom, and R ¹⁰ to R ¹² are Each independently represents a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.)

In the compound represented by the general formula (2), examples of the halogen atom represented by R ⁵ to R ⁹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the hydrocarbon group having 1 to 6 carbon atoms include a linear or cyclic saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, and an aromatic hydrocarbon group. Specifically, methyl, ethyl, propyl, i-propyl, butyl, 2-butyl, i-butyl, t-butyl, pentyl, 2-pentyl, 3-pentyl, linear saturated aliphatic hydrocarbon groups such as i-pentyl group, hexyl group, 2-hexyl group and 3-hexyl group; unsaturated aliphatic hydrocarbon groups such as vinyl group, allyl group, butenyl group, pentenyl group and hexenyl group A cycloaliphatic hydrocarbon group having 5 to 6 carbon atoms such as a cyclopentyl group and a cyclohexyl group; and an aromatic hydrocarbon group such as a phenyl group. Examples of the heterocyclic group having 4 to 6 carbon atoms include a thienyl group, a furanyl group, a pyridyl group, a tetrahydrothienyl group, a tetrahydrofuranyl group, and a piperidyl group.

Examples of the hydrocarbon group having 1 to 6 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom include a linear saturated aliphatic hydrocarbon group in which one or more hydrogen atoms are substituted with a fluorine atom, An unsaturated aliphatic hydrocarbon group in which at least one hydrogen atom has been replaced with a fluorine atom, a cyclic saturated aliphatic hydrocarbon group having at least one hydrogen atom replaced with a fluorine atom, and at least one hydrogen atom having a fluorine atom; And a substituted phenyl group. Examples of the chain saturated aliphatic hydrocarbon group, unsaturated aliphatic hydrocarbon group and cyclic saturated aliphatic hydrocarbon group include the above-mentioned chain saturated aliphatic hydrocarbon group, unsaturated aliphatic hydrocarbon group, and cyclic saturated aliphatic group. And a hydrocarbon group.

Examples of the chain saturated aliphatic hydrocarbon group in which one or more hydrogen atoms have been substituted with a fluorine atom include, for example, fluoromethyl group, difluoromethyl group, trifluoromethyl group, 1-fluoroethyl group, 2-fluoroethyl Group, 1-fluoroisopropyl group, 2-fluoroisopropyl group, 1-fluorobutyl group, 2-fluorobutyl group, 3-fluorobutyl group, 1-fluoroisobutyl group, 2-fluoroisobutyl group, 2-fluoro-t- Examples thereof include a butyl group, a 1-fluoropentyl group, a 2-fluoropentyl group, a 3-fluoropentyl group, a 4-fluoropentyl group, and a 1-fluorohexyl group.
Examples of the cyclic saturated aliphatic hydrocarbon group in which one or more hydrogen atoms have been substituted with fluorine atoms include a fluorocyclopentyl group and a fluorocyclohexyl group.
Examples of the aromatic hydrocarbon group in which one or more hydrogen atoms have been replaced by fluorine atoms include a fluorophenyl group, a difluorophenyl group, a trifluorophenyl group, and the like.
Examples of the heterocyclic group in which one or more hydrogen atoms are substituted with a fluorine atom include a fluorothienyl group, a fluorofuranyl group, a fluoropyridyl group, a fluorothiolanyl group, a fluorooxanyl group, a fluoropiperidyl group, and the like. Can be

As the halogen atom represented by R ¹⁰ to R ¹² and the hydrocarbon group having 1 to 6 carbon atoms in the compound represented by the general formula (2), those similar to R ⁵ to R ⁹ can be mentioned. Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, an i-propoxy group, a butoxy group, a pentoxy group, a hexyloxy group and a cyclohexyloxy group.

Among the compounds represented by the general formula (2), compounds in which R ⁵ to R ⁹ are a hydrogen atom or a halogen atom and R ¹⁰ to R ¹² are a methyl group include, for example, the following compound Nos. 2-1 to No. 2-6.

Among the compounds represented by the general formula (2), any one of R ⁵ to R ⁹ is a saturated aliphatic hydrocarbon group and R ¹⁰ to R ¹² is a methyl group. 2-7 to No. 2-23.

Among the compounds represented by the general formula (2), as a compound in which any of R ⁵ to R ⁹ is an unsaturated aliphatic hydrocarbon group and R ¹⁰ to R ¹² is a methyl group, for example, the following compound No. . 2-24 to No. 2-32.

Among the compounds represented by the general formula (2), compounds in which any of R ⁵ to R ⁹ is a cyclic aliphatic hydrocarbon group or a phenyl group and R ¹⁰ to R ¹² are a methyl group include, for example, Compound No. 2-33-No. 2-35.

Among the compounds represented by the general formula (2), any of R ⁵ to R ⁹ is a heterocyclic group, and R ¹⁰ to R ¹² are methyl groups. 2-36-No. 2-41.

In the compound represented by the general formula (2), any of R ⁵ to R ⁹ is a hydrocarbon group having 1 to 6 carbon atoms in which one or more hydrogen atoms are substituted with a fluorine atom, ^As a compound in which ¹⁰ to R ¹² are a methyl group, for example, the following compound No. 2-42 to No. 2-54.

In the compound represented by the general formula (2), any of R ⁵ to R ⁹ is a heterocyclic group in which one or more hydrogen atoms are substituted with a fluorine atom, and R ¹⁰ to R ¹² are a methyl group. For example, the following compound No. 2-55-No. 2-60.

R ⁵ to R ⁹ of the compound represented by the general formula (2) have excellent cycle characteristics and rate characteristics, and are easily available as raw materials. It is preferably a hydrogen group, more preferably a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. In addition, a hydrogen atom, a fluorine atom, a methyl group, or a vinyl group is also preferable because excellent battery characteristics are obtained, raw materials are easily available, and synthesis is simple. From these points, it is most preferable that R ⁵ to R ⁹ be a hydrogen atom.

Among the compounds represented by the general formula (2), compounds in which R ⁵ to R ⁹ are hydrogen atoms include, for example, the following compound Nos. 2-61 ~ No. 2-127.

As R ¹⁰ to R ¹² of the compound represented by the general formula (2), an aliphatic hydrocarbon group having 1 to 6 carbon atoms, particularly 1 to 4 carbon atoms is preferable because of excellent cycle characteristics and rate characteristics. It is preferred that Further, as R ¹⁰ to R ¹² , a methyl group, a vinyl group or a phenyl group is preferable, and a methyl group is more preferable, because excellent battery characteristics are obtained, raw materials are easily available, and synthesis is simple. .

The content of the compound represented by the general formula (2) is preferably from 0.1% by mass to 20% by mass, more preferably from 0.1% by mass to 10% by mass, and more preferably from 0.1% by mass to 10% by mass based on the whole nonaqueous electrolyte. It is more preferably from 5% by mass to 7.0% by mass, most preferably from 1% by mass to 5% by mass. When the content is 0.1% by mass or more, a sufficient effect can be exhibited, and when the content is 20% by mass or less, an effect of increasing the amount commensurate with the addition amount is observed, and the battery performance due to an excessive amount of the compound is obtained. Can be prevented more reliably.

非 The non-aqueous electrolyte used in the present invention may contain a known electrolyte additive such as an electrode film forming agent, an antioxidant, a flame retardant, an overcharge inhibitor, etc. for the purpose of improving battery life, improving safety, and the like. When the electrolyte additive is used, the concentration in the electrolyte is 0.01% by mass with respect to the entire nonaqueous electrolyte, from the viewpoint of exerting the addition effect and not adversely affecting the characteristics of the nonaqueous electrolyte secondary battery. It is preferably from 10% by mass to 10% by mass, more preferably from 0.1% by mass to 5% by mass.

The non-aqueous electrolyte used in the present invention includes the compound represented by the general formula (1) and the lithium salt, and if necessary, the compound represented by the general formula (2) and other electrolyte additives in the liquid electrolyte or the like. Can be prepared by mixing The mixing method is not particularly limited, and mixing may be performed by a known method.

<Non-aqueous electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present invention can be manufactured by interposing a non-aqueous electrolyte containing the compound represented by the general formula (1) and the lithium salt between the positive electrode and the negative electrode. In the nonaqueous electrolyte secondary battery of the present invention, it is preferable to use a separator between the positive electrode and the negative electrode. Hereinafter, the nonaqueous electrolyte secondary battery of the present invention will be described.

(Separator)
As the separator, a commonly used polymer film can be used without particular limitation. Examples of the polymer film include, for example, polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide, polypropylene oxide, and the like. It is composed of polyethers, various celluloses such as carboxymethylcellulose and hydroxypropylcellulose, polymer compounds mainly composed of poly (meth) acrylic acid and various esters thereof, derivatives thereof, and copolymers and mixtures thereof. Films and the like can be mentioned. These films are coated with ceramic materials such as alumina and silica, magnesium oxide, aramid resin, and polyvinylidene fluoride. There is. These films can be used alone, and can be used as a multilayer film by laminating these films. Furthermore, various additives can be used for these films, and the types and contents thereof are not particularly limited. Among these films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used for a secondary battery manufactured by a method for manufacturing a secondary battery.

フィルム These films are finely porous so that the electrolyte can be easily absorbed and ions can easily pass therethrough. The microporous method includes a phase separation method in which a film of a polymer compound and a solvent is formed while microphase-separating the solution, and the solvent is extracted and removed to form a porous layer. The film is extruded to form a film, and then heat-treated, the crystals are arranged in one direction, and a gap is formed between the crystals by stretching to make the crystal porous, and the like.

(shape)
The shape of the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, and may be various shapes such as a coin shape, a cylindrical shape, a square shape, and a laminate type. FIG. 1 shows an example of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention, and FIGS. 2 and 3 show examples of a cylindrical battery.

In the coin-type non-aqueous electrolyte secondary battery 10 shown in FIG. 1, 1 is a positive electrode capable of releasing lithium ions, 1a is a positive electrode current collector, 2 is a negative electrode capable of absorbing and releasing lithium ions released from the positive electrode, and 2a is A negative electrode current collector, 3 is a non-aqueous electrolyte, 4 is a positive electrode case made of stainless steel, 5 is a negative electrode case made of stainless steel, 6 is a gasket made of polypropylene, and 7 is a separator made of polyethylene.

In the cylindrical non-aqueous electrolyte secondary battery 10 'shown in FIGS. 2 and 3, 11 is a negative electrode, 12 is a negative electrode current collector, 13 is a positive electrode, 14 is a positive electrode current collector, 15 is a non-aqueous electrolyte, 16 is a separator, 17 is a positive electrode terminal, 18 is a negative electrode terminal, 19 is a negative electrode plate, 20 is a negative electrode lead, 21 is a positive electrode plate, 22 is a positive electrode lead, 23 is a case, 24 is an insulating plate, 25 is a gasket, and 26 is a safety valve. , 27 are PTC elements.

(External packaging)
As the external packaging member, a laminated film or a metal container can be used. The thickness of the packaging member is usually 0.5 mm or less, preferably 0.3 mm or less. Examples of the shape of the packaging member include a flat type (thin type), a square type, a cylindrical type, a coin type, and a button type.

The laminate film may be a multilayer film having a metal layer between resin films. The metal layer is preferably an aluminum foil or an aluminum alloy foil for weight reduction. As the resin film, for example, a polymer material such as polypropylene, polyethylene, nylon, or polyethylene terephthalate can be used. The laminate film can be formed into a shape of an exterior member by performing sealing by heat fusion.

The metal container can be formed from, for example, stainless steel, aluminum, or an aluminum alloy. As the aluminum alloy, an alloy containing an element such as magnesium, zinc, or silicon is preferable. By making the content of transition metals such as iron, copper, nickel, and chromium into aluminum or an aluminum alloy to 1% or less, long-term reliability and heat dissipation under a high-temperature environment can be dramatically improved.

Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment. The present invention can be implemented in various forms with modifications, improvements, and the like that can be made by those skilled in the art without departing from the gist of the present invention.

本 Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited at all by the following examples. In the examples, “parts” and “%” are based on mass unless otherwise specified.

<Example 1>
(Preparation of positive electrode)
90.0 parts by mass of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (D50 = 10.6 μm) as a positive electrode active material, 5.0 parts by mass of acetylene black (manufactured by Denka Corporation) as a conductive additive, Using 5.0 parts by mass of polyvinylidene fluoride (manufactured by Kureha Corporation) as a binder and 80 parts by mass of N-methylpyrrolidone as a solvent, mixing was performed by a rotation / revolution mixer to obtain an electrode mixture paste. The electrode mixture paste was applied to a current collector made of aluminum foil (thickness: 20 μm) by a doctor blade method, and allowed to stand at 90 ° C. for 3 hours and dried. Further, press molding was performed. Thereafter, the electrode was cut into a predetermined size, and further dried under vacuum at 150 ° C. for 2 hours immediately before use to produce a positive electrode.

(Preparation of negative electrode A)
80.0 parts by mass (50.1 parts by mass of silicon atom) of carbon coat SiO _x (x = 1.0, D50 = 5.4 μm) as a negative electrode active material, and acetylene black (manufactured by Denka Corporation) as a conductive auxiliary agent Using 5.0 parts by mass, 15.0 parts by mass of a polyimide resin (Dream Bond, manufactured by IST) as a binder, and 100 parts by mass of N-methylpyrrolidone as a solvent, mixed by a rotation / revolution mixer, An electrode mixture paste was obtained. The electrode mixture paste is applied to a current collector made of stainless steel foil (thickness: 10 μm) by a doctor blade method, left standing at 90 ° C. for 3 hours, dried, and further left under vacuum at 350 ° C. for 3 hours. And dried. Thereafter, this electrode was cut into a predetermined size, and further vacuum-dried at 150 ° C. for 2 hours immediately before use to prepare a negative electrode A.

(Battery assembly)
Ethylene carbonate 30 vol%, the dimethyl carbonate 30% by volume of a mixed solvent consisting of ethyl methyl carbonate from 40 vol%, the LiPF ₆ 1.0 mol / L, compound No. 1-1 was dissolved to a concentration of 0.5% by mass to prepare a non-aqueous electrolyte.
The positive electrode and the negative electrode A were held in a case with a glass filter as a separator. Thereafter, the previously prepared non-aqueous electrolyte was injected into the case, and sealed and sealed with a caulking machine to produce a coin-type non-aqueous electrolyte secondary battery of Example 1. The negative electrode A was prepared by dissolving 1.0 mol / L of LiPF ₆ in a mixed solvent of 30% by volume of ethylene carbonate, 30% by volume of dimethyl carbonate, and 40% by volume of ethyl methyl carbonate, using lithium metal as a counter electrode. A half-cell was assembled as an electrolyte, and an electrochemically doped lithium was used.

<Example 2>
A coin-type non-aqueous electrolyte secondary battery of Example 2 was produced in the same manner as in Example 1, except that Compound No. 1-1 was dissolved in the mixed solvent at a concentration of 1.0% by mass.

<Example 3>
A coin-type nonaqueous electrolyte secondary battery of Example 3 was produced in the same manner as in Example 1, except that Compound No. 1-1 was dissolved in the mixed solvent at a concentration of 2.0% by mass.

<Example 4>
A coin-type nonaqueous electrolyte secondary battery of Example 4 was produced in the same manner as in Example 1, except that Compound No. 1a-29 was dissolved in the above-mentioned mixed solvent at a concentration of 0.5% by mass.

<Example 5>
A coin-type nonaqueous electrolyte secondary battery of Example 5 was produced in the same manner as in Example 1, except that Compound No. 1a-29 was dissolved in the above mixed solvent at a concentration of 1.0% by mass.

<Example 6>
A coin-type nonaqueous electrolyte secondary battery of Example 6 was produced in the same manner as in Example 1, except that Compound No. 1a-29 was dissolved in the mixed solvent at a concentration of 2.0% by mass.

<Example 7>
A coin-type nonaqueous electrolyte secondary battery of Example 7 was produced in the same manner as in Example 1, except that Compound No. 1a-92 was dissolved in the above mixed solvent at a concentration of 0.5% by mass.

<Example 8>
A coin-type nonaqueous electrolyte secondary battery of Example 8 was produced in the same manner as in Example 1, except that Compound No. 1a-92 was dissolved in the above mixed solvent at a concentration of 1.0% by mass.

<Example 9>
A coin-type nonaqueous electrolyte secondary battery of Example 9 was produced in the same manner as in Example 1, except that Compound No. 1a-92 was dissolved in the above mixed solvent at a concentration of 2.0% by mass.

<Example 10>
Compound No. 1-1 was added at a concentration of 1.0% by mass, and Compound No. 1-1 was used. A coin-type non-aqueous electrolyte secondary battery of Example 10 was produced in the same manner as in Example 1, except that 2-1 was dissolved in the mixed solvent at a concentration of 1.0% by mass.

<Example 11>
Compound No. 1a-29 was added at a concentration of 1.0% by mass and Compound No. 1a-29 was added. A coin-type non-aqueous electrolyte secondary battery of Example 11 was produced in the same manner as in Example 1, except that 2-1 was dissolved in the mixed solvent at a concentration of 1.0% by mass.

<Example 12>
Compound No. 1a-92 was added at a concentration of 1.0% by mass and Compound No. 1a-92 was added. A coin-type nonaqueous electrolyte secondary battery of Example 12 was produced in the same manner as in Example 1, except that 2-1 was dissolved in the above-mentioned mixed solvent at a concentration of 1.0% by mass.

<Example 13>
Further, a coin-type non-aqueous electrolyte secondary battery of Example 13 was produced in the same manner as in Example 1, except that vinylene carbonate was dissolved in the mixed solvent at a concentration of 0.5% by mass.

<Example 14>
Further, a coin-type nonaqueous electrolyte secondary battery of Example 14 was produced in the same manner as in Example 4, except that vinylene carbonate was dissolved in the mixed solvent at a concentration of 0.5% by mass.

<Example 15>
Further, a coin-type non-aqueous electrolyte secondary battery of Example 15 was produced in the same manner as in Example 7, except that vinylene carbonate was dissolved in the mixed solvent at a concentration of 0.5% by mass.

<Example 16>
(Preparation of negative electrode B)
As the negative electrode active material, 9.0 parts by mass of carbon-coated SiO _x (x = 1.0, D50 = 5.4 μm) (5.6 parts by mass as silicon atom weight) and artificial graphite (D50 = 21.3 μm) were used. 0 parts by mass, 5.0 parts by mass of acetylene black (manufactured by Denka) as a conductive aid, 3.0 parts by mass of styrene-butadiene rubber (40 mass% aqueous dispersion, manufactured by Zeon Corporation) as a binder, and carboxymethyl cellulose Using 2.0 parts by mass of sodium (CMCNa: manufactured by Daicel Finechem) and 100 parts by mass of water as a solvent, the mixture was mixed by a rotation / revolution mixer to obtain an electrode mixture paste. The electrode mixture paste was applied to a current collector made of copper foil (thickness: 10 μm) by a doctor blade method, and allowed to stand at 90 ° C. for 3 hours and dried. Further, press molding was performed. Thereafter, this electrode was cut into a predetermined size, and further dried immediately before use at 150 ° C. for 2 hours under vacuum to prepare a negative electrode B.

コイン A coin-type non-aqueous electrolyte secondary battery of Example 16 was produced in the same manner as in Example 2, except that the negative electrode B was used instead of the negative electrode A.

<Example 17>
A coin-type non-aqueous electrolyte secondary battery of Example 17 was produced in the same manner as in Example 5, except that the negative electrode B was used instead of the negative electrode A.

<Example 18>
A coin-type nonaqueous electrolyte secondary battery of Example 18 was produced in the same manner as in Example 8, except that the negative electrode B was used instead of the negative electrode A.

<Example 19>
(Preparation of negative electrode C)
80.0 parts by mass of Si (D50 = 2.8 μm) as a negative electrode active material, 5.0 parts by mass of acetylene black (manufactured by Denka) as a conductive aid, and a polyimide resin (Dream Bond, IST) as a binder 15.0 parts by mass) and 100 parts by mass of N-methylpyrrolidone as a solvent were mixed by a rotation / revolution mixer to obtain an electrode mixture paste. The electrode mixture paste was applied to a current collector made of copper foil (thickness: 10 μm) by a doctor blade method, and allowed to stand at 90 ° C. for 3 hours and dried. Thereafter, the electrode was cut into a predetermined size, and further dried immediately before use at 150 ° C. for 2 hours under vacuum to produce a negative electrode C.

コイン A coin-type nonaqueous electrolyte secondary battery of Example 19 was produced in the same manner as in Example 1, except that the negative electrode C was used instead of the negative electrode A.

<Example 20>
A coin-type non-aqueous electrolyte secondary battery of Example 20 was produced in the same manner as in Example 2, except that the negative electrode C was used instead of the negative electrode A.

<Example 21>
A coin-type nonaqueous electrolyte secondary battery of Example 21 was produced in the same manner as in Example 3, except that the negative electrode C was used instead of the negative electrode A.

<Example 22>
A coin-type nonaqueous electrolyte secondary battery of Example 22 was produced in the same manner as in Example 4, except that the negative electrode C was used instead of the negative electrode A.

<Example 23>
A coin-type nonaqueous electrolyte secondary battery of Example 23 was made in the same manner as in Example 5, except that the negative electrode C was used instead of the negative electrode A.

<Example 24>
A coin-type nonaqueous electrolyte secondary battery of Example 24 was made in the same manner as in Example 6, except that the negative electrode C was used instead of the negative electrode A.

<Example 25>
A coin-type nonaqueous electrolyte secondary battery of Example 25 was made in the same manner as in Example 7, except that the negative electrode C was used instead of the negative electrode A.

<Example 26>
A coin-type nonaqueous electrolyte secondary battery of Example 26 was made in the same manner as in Example 8, except that the negative electrode A was used instead of the negative electrode A.

<Example 27>
A coin-type nonaqueous electrolyte secondary battery of Example 27 was made in the same manner as Example 9 except that the negative electrode C was used instead of the negative electrode A.

<Example 28>
A coin-type nonaqueous electrolyte secondary battery of Example 28 was produced in the same manner as in Example 10, except that the negative electrode C was used instead of the negative electrode A.

<Example 29>
A coin-type non-aqueous electrolyte secondary battery of Example 29 was produced in the same manner as in Example 11, except that the negative electrode C was used instead of the negative electrode A.

<Example 30>
A coin-type non-aqueous electrolyte secondary battery of Example 30 was produced in the same manner as in Example 12, except that the negative electrode C was used instead of the negative electrode A.

<Example 31>
A coin-type nonaqueous electrolyte secondary battery of Example 31 was produced in the same manner as in Example 13, except that the negative electrode C was used instead of the negative electrode A.

<Example 32>
A coin-type nonaqueous electrolyte secondary battery of Example 32 was produced in the same manner as in Example 14, except that the negative electrode C was used instead of the negative electrode A.

<Example 33>
A coin-type nonaqueous electrolyte secondary battery of Example 33 was made in the same manner as Example 15 except that the negative electrode C was used instead of the negative electrode A.

<Example 34>
(Preparation of negative electrode D)
9.0 parts by mass of Si (D50 = 2.8 μm) and 81.0 parts by mass of artificial graphite (D50 = 21.3 μm) as a negative electrode active material, and 5.0 of acetylene black (manufactured by Denka) as a conductive aid. Parts by mass, 3.0 parts by mass of a styrene-butadiene rubber (40 mass% aqueous dispersion, manufactured by Zeon Corporation) as a binder, 2.0 parts by mass of sodium carboxymethyl cellulose (CMCNa: manufactured by Daicel Finechem), and water as a solvent. Was mixed with a rotation / revolution mixer to obtain an electrode mixture paste. The electrode mixture paste was applied to a current collector made of copper foil (thickness: 10 μm) by a doctor blade method, and allowed to stand at 90 ° C. for 3 hours and dried. Further, press molding was performed. Thereafter, this electrode was cut into a predetermined size, and further vacuum-dried at 150 ° C. for 2 hours immediately before use to prepare a negative electrode D.

コイン A coin-type nonaqueous electrolyte secondary battery of Example 34 was produced in the same manner as in Example 2, except that the negative electrode A was used instead of the negative electrode A.

<Example 35>
A coin-type nonaqueous electrolyte secondary battery of Example 35 was produced in the same manner as in Example 5, except that the negative electrode D was used instead of the negative electrode A.

<Example 36>
A coin-type nonaqueous electrolyte secondary battery of Example 36 was made in the same manner as in Example 8, except that the negative electrode A was used instead of the negative electrode A.

<Comparative Example 1>
Compound No. A coin-type non-aqueous electrolyte secondary battery of Comparative Example 1 was produced in the same manner as in Example 1 except that a non-aqueous electrolyte was prepared without using 1-1.

<Comparative Example 2>
Compound No. A coin-type nonaqueous electrolyte secondary battery of Comparative Example 2 was produced in the same manner as in Example 1, except that vinylene carbonate was dissolved at a concentration of 1.0% by mass instead of 1-1.

<Comparative Example 3>
Compound No. A coin-type nonaqueous electrolyte secondary battery of Comparative Example 3 was produced in the same manner as in Example 1, except that fluoroethylene carbonate was dissolved at a concentration of 1.0% by mass instead of 1-1.

<Comparative Example 4>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 4 was produced in the same manner as in Comparative Example 1 except that the negative electrode B was used instead of the negative electrode A.

<Comparative Example 5>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 5 was produced in the same manner as in Comparative Example 2 except that the negative electrode B was used instead of the negative electrode A.

<Comparative Example 6>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 6 was produced in the same manner as Comparative Example 3 except that the negative electrode B was used instead of the negative electrode A.

<Comparative Example 7>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 7 was produced in the same manner as in Comparative Example 1, except that the negative electrode C was used instead of the negative electrode A.

<Comparative Example 8>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 8 was produced in the same manner as in Comparative Example 2 except that the negative electrode C was used instead of the negative electrode A.

<Comparative Example 9>
A coin-type non-aqueous electrolyte secondary battery of Comparative Example 9 was produced in the same manner as Comparative Example 3 except that the negative electrode C was used instead of the negative electrode A.

<Comparative Example 10>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 10 was produced in the same manner as in Comparative Example 1 except that the negative electrode A was used instead of the negative electrode A.

<Comparative Example 11>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 11 was produced in the same manner as in Comparative Example 2 except that the negative electrode D was used instead of the negative electrode A.

<Comparative Example 12>
A coin-type nonaqueous electrolyte secondary battery of Comparative Example 12 was produced in the same manner as in Comparative Example 3 except that the negative electrode D was used instead of the negative electrode A.

<Charge / discharge evaluation>
The coin-type non-aqueous electrolyte secondary batteries of Examples 1 to 36 and Comparative Examples 1 to 12 were placed in a thermostat at 30 ° C., the charge end voltage was set to 4.3 V, the discharge end voltage was set to 2.5 V, and the charge rate was set to 0. 10 cycles of a charge / discharge test at 0.2 C and a discharge rate of 0.2 C were performed. Thereafter, 100 cycles of a charge / discharge test at a charge rate of 1.0 C and a discharge rate of 1.0 C, 100 cycles of a charge / discharge test at a charge rate of 2.0 C and a discharge rate of 2.0 C, and a charge rate of 3.0 C and a discharge rate of 3 A 100 C charge / discharge test was performed for 100 cycles, for a total of 310 cycles. Tables 1 and 2 show the ratio (capacity retention) of the discharge capacity at the 110th, 160th, and 260th cycles to the discharge capacity at the 20th cycle. Capacity retention rate 1 = discharge capacity of 110 cycles / discharge capacity of 20 cycles, capacity retention rate 2 = discharge capacity of 160 cycles / discharge capacity of 20 cycles, capacity retention rate 3 = discharge capacity of 260 cycles / discharge capacity of 20 cycles It is.

As shown in Table 1, the nonaqueous electrolyte secondary batteries of Examples 1 to 36 have higher capacity retention ratios and superior cycle characteristics than the nonaqueous electrolyte secondary batteries of Comparative Examples 1 to 12. Thus, the non-aqueous electrolyte secondary battery had a high capacity retention rate even when the charge / discharge rate was high and had excellent rate characteristics.

REFERENCE SIGNS LIST 1 positive electrode 1 a positive electrode current collector 2 negative electrode 2 a negative electrode current collector 3 nonaqueous electrolyte 4 positive electrode case 5 negative electrode case 6 gasket 7 separator 10 coin-type nonaqueous electrolyte secondary battery 10 ′ cylindrical nonaqueous electrolyte secondary battery 11 negative electrode 12 Negative electrode current collector 13 Positive electrode 14 Positive electrode current collector 15 Nonaqueous electrolyte 16 Separator 17 Positive terminal 18 Negative terminal 19 Negative plate 20 Negative lead 21 Positive plate 22 Positive lead 23 Case 24 Insulating plate 25 Gasket 26 Safety valve 27 PTC element

Claims

A positive electrode,
A negative electrode containing a silicon atom,
A non-aqueous electrolyte containing the compound represented by the general formula (1) and a lithium salt;
Non-aqueous electrolyte secondary battery containing.

(Wherein, R 1 to R 3 each independently represent a hydrocarbon group having 1 to 10 carbon atoms, R 4 is an n-valent hydrocarbon group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms) An n-valent group in which 10 hydrocarbon groups are linked by an oxygen atom or a sulfur atom, or an n-valent heterocyclic group having 3 to 6 carbon atoms containing an oxygen atom or a sulfur atom, wherein n is 1 to 6 Represents an integer.)
R 4 of the compound represented by the general formula (1) is an n-valent aliphatic hydrocarbon group having 2 to 10 carbon atoms, or an n-valent hydrocarbon group having 1 to 10 carbon atoms connected by a sulfur atom. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein n represents 2 or a n-valent heterocyclic group having 3 to 6 carbon atoms including a sulfur atom.
The non-aqueous electrolyte secondary battery according to claim 1, wherein the content of the compound represented by the general formula (1) is 0.01% by mass to 20% by mass in the non-aqueous electrolyte.
The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the non-aqueous electrolyte further contains a compound represented by the general formula (2).

(Wherein, R 5 to R 9 each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a heterocyclic group having 4 to 6 carbon atoms, and at least one hydrogen atom Represents a hydrocarbon group having 1 to 6 carbon atoms substituted by a fluorine atom, or a heterocyclic group having 4 to 6 carbon atoms substituted by one or more hydrogen atoms by a fluorine atom, and R 10 to R 12 are Each independently represents a halogen atom, a hydrocarbon group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.)
R 5 to R 9 of the compound represented by the general formula (2) are each independently a hydrogen atom or an aliphatic hydrocarbon group having 1 to 6 carbon atoms, and R 10 to R 12 are each independently a carbon atom. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the non-aqueous electrolyte secondary battery is an aliphatic hydrocarbon group having 1 to 6 atoms.
The negative electrode according to any one of claims 1 to 5, wherein the negative electrode contains SiO x (x = 0.5 to 1.6) that may have a carbon coat or elemental silicon that may have a carbon coat. Non-aqueous electrolyte secondary battery.
The non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, wherein the average particle diameter of the SiO x or the elemental silicon is 0.01 to 50 μm.
(8) The nonaqueous electrolyte secondary battery according to any one of (1) to (7), wherein the content of silicon atoms in the electrode mixture layer of the negative electrode is 1% by mass to 98% by mass.
In the compound represented by the general formula (1), R 4 is an n-valent aliphatic hydrocarbon group having 2 to 6 carbon atoms, and an aliphatic hydrocarbon group having 1 to 6 carbon atoms connected by a sulfur atom. represents an n-valent group or an n-valent heterocyclic group having 1 to 6 carbon atoms containing a sulfur atom, wherein n is 2 and R 1 to R 3 each independently represent a carbon atom having 1 to 6 carbon atoms; Represents a hydrogen group,
9. The negative electrode according to claim 1, wherein the negative electrode contains SiO x (x = 0.5 to 1.6) that may have a carbon coat or elemental silicon that may have a carbon coat. Non-aqueous electrolyte secondary battery.
(10) The nonaqueous electrolyte secondary battery according to any one of (1) to (9), wherein the negative electrode further contains a carbon material.