JP2011210666A - Resin coated active material for nonaqueous secondary battery electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active material which can improve input/output characteristics and cycle characteristics in a low temperature with a sufficient balance when used as an electrode of a nonaqueous secondary battery.SOLUTION: The resin coated active material for a nonaqueous secondary battery electrode has a resin composition (C) containing a cellulose system polymer or its metal salt (A) and an alkaline metal salt (B)(however, the alkaline metal slat (B) shall not be an alkaline metal salt of a cellulose system polymer) covering at least a part of a surface of the active material. A nonaqueous secondary battery including the active material layer containing the resin coated active material and a nonaqueous secondary battery provided with the electrode as an anode are provided.

Description

  The present invention relates to an active material used for an electrode for a non-aqueous secondary battery. More specifically, the specific resin composition covers at least a part of the surface of the active material. The present invention relates to a resin-coated active material for a secondary battery electrode. Moreover, this invention relates to the electrode for non-aqueous secondary batteries provided with the active material layer containing a resin coating active material, and the non-aqueous secondary battery provided with this electrode as a negative electrode.

  With the recent reduction in weight and size of electrical products, development of non-aqueous secondary batteries having high energy density, in particular lithium ion secondary batteries, is being promoted. As the application field of lithium ion secondary batteries expands, further improvements in battery characteristics are required, and among them, there is a strong demand for improving input / output characteristics and cycle characteristics at low temperatures in a balanced manner.

  Until now, efforts to improve the characteristics of lithium ion secondary batteries have been centered on the development of non-aqueous electrolytes used and the development of active materials. It extends to surface treatment.

  As a surface treatment of the active material, a treatment of covering the active material particles with a porous lithium ion conductive polymer film has been proposed (Patent Document 1). Moreover, the process (patent document 2) which adsorb | sucks or coat | covers surface active effect materials, such as a starch derivative and viscous polysaccharide, to the graphite powder for negative electrodes is proposed.

JP-A-9-219197 WO1999 / 001904

  However, since the method of Patent Document 1 requires an organic solvent for dissolving the polymer during the adhering treatment, it has a large environmental burden and further requires equipment for recovering the organic solvent during drying. Further, when the active material surface is covered with a porous lithium ion conductive polymer film, there is a problem that the cycle characteristics are significantly deteriorated. The method of Patent Document 2 has a problem that the ionic conductivity of starch derivatives and viscous polysaccharides is low and the input / output characteristics are poor. Thus, the present condition is that the further improvement is requested | required with respect to the input / output characteristic and cycling characteristics in the low temperature of a lithium ion secondary battery.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a resin composition (C) containing a cellulosic polymer or a metal salt (A) thereof and an alkali metal salt (B) (however, an alkali metal (B ) Is not an alkali metal salt of a cellulosic polymer), but a resin-coated active material covering at least a part of the surface of the active material is applied to an electrode of a non-aqueous secondary battery, particularly a lithium ion secondary battery. When used, it has been found that the input / output characteristics and cycle characteristics at low temperatures can be improved in a balanced manner, and the present invention has been completed.

The present invention relates to a resin composition (C) comprising a cellulosic polymer or a metal salt (A) thereof and an alkali metal salt (B) (wherein the alkali metal salt (B) is an alkali metal salt of a cellulosic polymer). The present invention relates to a resin-coated active material for a non-aqueous secondary battery electrode, characterized in that at least a part of the surface of the active material is coated.
The present invention relates to the resin-coated active material for a non-aqueous secondary battery electrode, wherein the alkali metal salt (B) is 1% by mass or more with respect to 100% by mass of the resin composition (C).
The present invention provides a resin for a non-aqueous secondary battery electrode according to any one of the above, which is obtained by mixing the resin composition (C) and the active material in an aqueous solvent and then repeating the drying step one or more times. It relates to a coated active material.
The present invention relates to the resin-coated active material for a non-aqueous secondary battery electrode as described above, wherein the alkali metal salt (B) is at least one selected from the group consisting of organic salts, inorganic salts and complex salts.
The present invention further provides the nonaqueous secondary battery electrode according to any one of the above, further comprising a hydrophilic polymer (D) (provided that the polymer is not a cellulosic polymer) on at least a part of the surface of the active material. The present invention relates to a resin-coated active material.
The present invention further relates to any one of the above resin-coated active materials for non-aqueous secondary battery electrodes, which has a rubber-based polymer (E) on at least a part of the surface of the active material.
The present invention further relates to any one of the above resin-coated active materials for non-aqueous secondary battery electrodes, which has a conductive additive (F) on at least a part of the surface of the active material.
The present invention relates to any one of the above resin-coated active materials for non-aqueous secondary battery electrodes using an active material capable of occluding and releasing lithium ions.

  The present invention also relates to a non-aqueous secondary battery electrode, particularly a lithium ion secondary battery electrode, comprising an active material layer containing any of the above resin-coated active materials on a current collector, The present invention relates to a negative electrode for a non-aqueous secondary battery, particularly a negative electrode for a lithium ion secondary battery, in which the active material layer is a negative electrode active material layer and further contains a thickener and a rubber polymer. The present invention relates to a non-aqueous secondary battery including the above-described negative electrode, positive electrode, and electrolyte, and more particularly to a lithium ion secondary battery.

  When the resin-coated active material of the present invention is used for an electrode of a non-aqueous secondary battery, particularly a lithium ion secondary battery, the input / output characteristics and cycle characteristics at low temperatures can be improved in a balanced manner. Since the electrode using the resin-coated active material of the present invention can be prepared using an aqueous solvent, the load on the environment is small and the cost performance is excellent.

The present invention relates to a resin composition (C) comprising a cellulosic polymer or a metal salt (A) thereof and an alkali metal salt (B) (wherein the alkali metal salt (B) is an alkali metal salt of a cellulosic polymer). The present invention relates to a resin-coated active material for a non-aqueous secondary battery electrode, characterized in that at least a part of the surface of the active material is coated.
Here, “covered” refers to a state in which it is adsorbed on at least a part of the surface of the active material, and is different from a mixed state such as when it is simply mixed with the active material. Adsorption may be chemical adsorption by hydrogen bonding or physical adsorption by van der Waals force, but is not limited thereto. Further, the surface of the active material refers to a site where the resin composition (C) can approach and can be adsorbed. That is, it also includes an inner wall surface of an opening that can enter the resin composition (C) inside the active material.

  Cellulosic polymers or metal salts thereof (A) include carboxymethylcellulose (CMC), methylcellulose, ethylcellulose, acetylcellulose, hydroxyethylcellulose, starch, carrageenan, pullulan, guar gum, xanthan gum (xanthan gum), hydroxypropylcellulose, hydroxypropylmethylcellulose And metal salts thereof. Among them, carboxymethyl cellulose or a metal salt thereof is preferable because it is excellent in covering power of the resin composition (C) with respect to the active material and has low swelling property to a non-aqueous electrolyte solution containing ethylene carbonate or the like.

  The carboxymethyl cellulose is not particularly limited, and preferably has a number of ether linkages of carboxymethyl groups to one unit of anhydrous glycol, that is, a degree of etherification of 0.5 to 1.5. Carboxymethyl cellulose has an average degree of polymerization of preferably 100 to 2,000, more preferably 800 to 1,500. When the average degree of polymerization of carboxymethyl cellulose is 800 to 1,500, it is advantageous in terms of coverage with respect to the active material, coatability, electrode strength, and cycle characteristics.

  The cellulose polymer or the metal salt (A) thereof may be used alone or in combination of two or more. Cellulose polymers and metal salts of cellulose polymers can be used in combination.

  The alkali metal salt (B) is not particularly limited as long as it is other than the alkali metal salt of the cellulosic polymer. Examples of the alkali metal in the alkali metal salt (B) include lithium, sodium, potassium, rubidium and cesium, and among them, lithium, sodium and potassium are preferable. When an alkali metal salt of a cellulosic polymer is used as the cellulosic polymer or a metal salt thereof (A), the alkali metal and the alkali metal in the alkali metal salt (B) may be the same or different. Also good.

  The alkali metal salt (B) can be an inorganic alkali metal salt, an organic alkali metal salt, or a complex salt. Specific examples include inorganic alkali metal salts such as sodium chloride, sodium carbonate, and sodium oxide; and organic alkali metal salts such as sodium glycolate, sodium acetate, and sodium citrate. When a ligand that forms a complex is contained in the resin composition (C), a complex salt of an alkali metal may be used.

  An alkali metal salt (B) may be individual, or may use 2 or more types together.

  The content of the cellulosic polymer or the metal salt (A) thereof in the resin composition (C) is not particularly limited, and may be 30% by mass or more with respect to 100% by mass of the resin composition (C). preferable. If it is 30 mass% or more, it is advantageous in terms of coverage with respect to the active material, coatability, electrode strength, and cycle characteristics. The content is more preferably 40% by mass or more, particularly preferably 45% by mass or more, and preferably 99% by mass or less, more preferably 96% by mass or less.

  Content of the alkali metal salt (B) in a resin composition (C) is not specifically limited, It is preferable that it is 1 mass% or more with respect to 100 mass% of resin compositions (C). If it is 1 mass% or more, it is advantageous in terms of ion conductivity and input / output characteristics of the coating. The content is more preferably 2% by mass or more, particularly preferably 4% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less.

  In the resin composition (C), the content of the alkali metal derived from the alkali metal salt (B) is 0.5 to 50% by mass in terms of metal with respect to 100% by mass of the resin composition (C). Is preferred. This range is advantageous in terms of ion conductivity and input / output characteristics of the coating. The content of the alkali metal derived from the alkali metal salt (B) can be measured by fluorescent X-ray analysis (XRF), inductively coupled plasma mass spectrometry (ICP-MS), or the like. Or the method of measuring the density | concentration of a counter anion and calculating | requiring content of an alkali metal from this density | concentration is mentioned. The content of the alkali metal derived from the alkali metal salt (B) is more preferably 1 to 40% by mass, and particularly preferably 5 to 30% by mass in terms of metal.

  The resin composition (C) can be prepared by blending the cellulosic polymer or its metal salt (A) and the alkali metal salt (B), and also the cellulosic polymer or its metal salt (A). The alkali metal salt produced as a by-product during the production of can be obtained by adjusting the degree of purification and leaving any amount, but this is not a limitation.

  The active material is not particularly limited, and a negative electrode active material is preferable, and a carbonaceous material is particularly preferable.

  The carbon material as the negative electrode active material is not particularly limited, and examples thereof include artificial graphite, graphite such as natural graphite (graphite), and thermal decomposition products of organic substances under various thermal decomposition conditions. Organic pyrolysis products include coal-based coke, petroleum-based coke, coal-based pitch carbide, petroleum-based pitch carbide, or carbides obtained by oxidizing these pitches, needle coke, pitch coke, phenolic resin, crystalline cellulose And carbon materials obtained by partially graphitizing these, furnace black, acetylene black, pitch-based carbon fibers, and the like. Of these, graphite is preferable, and artificial graphite, purified natural graphite, or graphite materials containing pitch in these graphites, which are manufactured by subjecting easy-graphite pitches obtained from various raw materials to high-temperature heat treatment, are more preferable. The surface treatment may be performed. These carbon materials may be used alone or in combination of two or more.

  In the case of using a graphite material, the d value (interlayer distance) of the lattice plane (002 plane) obtained by X-ray diffraction by the Gakushin method is preferably 0.335 nm or more, and preferably 0.34 nm or less. Preferably it is 0.337 nm or less.

  The ash content of the graphite material is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less with respect to the mass of the graphite material.

  The crystallite size (Lc) of the graphite material determined by X-ray diffraction by the Gakushin method is preferably 30 nm or more, more preferably 50 nm or more, and particularly preferably 100 nm or more.

  The median diameter of the graphite material obtained by the laser diffraction / scattering method is preferably 1 μm or more, more preferably 3 μm or more, further preferably 5 μm or more, particularly preferably 7 μm or more, and preferably 100 μm or less, more Preferably it is 50 micrometers or less, More preferably, it is 40 micrometers or less, Most preferably, it is 30 micrometers or less.

The BET specific surface area of the graphite material is preferably 0.5 m ² / g or more, more preferably 0.7 m ² / g or more, still more preferably 1.0 m ² / g or more, and particularly preferably 1.5 m ² / g. or more, also preferably 25.0 m ² / g or less, more preferably 20.0 m ² / g or less, more preferably 15.0 m ² / g or less, particularly preferably not more than 10.0 m ² / g .

Graphite material, when subjected to Raman spectrum analysis using an argon laser beam, the intensity _{I A} of the peak _{P A} is detected in the range of 1580～1620Cm ^-1, is detected in the range of 1350 ^-1 intensity ratio _I a / _{I B} of the intensity _{I B} of a peak _{P B} is what is preferably 0 to 0.5. Further, the half width of the peak _{P A} is preferably 26cm ^-1 or less, 25 cm ^-1 or less is more preferable.

  In addition to the carbon material described above, other materials capable of occluding and releasing lithium known as a negative electrode active material can also be used. Examples include metal oxides such as tin oxide and silicon oxide, sulfides and nitrides, lithium alloys such as lithium alone and lithium aluminum alloys, and the like. These materials other than carbon materials may be used alone or in combination of two or more. Moreover, you may use in combination with the above-mentioned carbon material.

  The amount of the resin composition (C) with respect to 100% by mass of the active material before coating is preferably 0.01 to 50% by mass. Within this range, it is easy to ensure good cycle characteristics and input / output characteristics. The amount is more preferably 0.1% by mass or more, and more preferably 30% by mass or less.

  The coating can be performed by coating at least part of the active material surface with the resin composition (C) in an aqueous solvent. Specifically, after the resin composition (C) and the active material are mixed in an aqueous solvent, the step of drying in an inert gas (for example, nitrogen gas) is preferably repeated one or more times to obtain a resin coating active. A substance can be obtained. Examples of the aqueous solvent include water or a mixed solvent of water and alcohol (for example, a lower alcohol such as ethanol).

The resin-coated active material is usually obtained in a state where the resin composition (C) covers at least a part of the active material, and examples of the form include a thin film shape, a spot shape, a lump shape, a shelf shape, and the like. Not done. Moreover, when using 2 or more types of resin compositions (C), each resin composition may coat | cover the active material surface independently, and may laminate | stack alternately or at random. The coating ratio of the resin composition (C) is preferably 0.01% or more, more preferably 0.1% with respect to the entire surface of the active material from the viewpoints of input / output, initial efficiency, electrode strength, and cycle characteristics. That's it. The coating ratio is a numerical value obtained by substituting the specific surface area before and after resin coating measured by the BET method into the following equation.
Covering ratio (%) = [(specific surface area before resin coating−specific surface area after resin coating) / specific surface area before resin coating] × 100

  In addition to the resin composition (C), the resin-coated active material may have a hydrophilic polymer (D) (provided that it is not a cellulosic polymer) on at least a part of the active material surface. Good. As the hydrophilic polymer (D), acrylic polymers (polyacrylic acid, polymethacrylic acid, polyalkyl acrylate, polyalkyl methacrylate, polyacrylamide, polymethacrylamide), ether polymers (polyethylene oxide, polypropylene) Oxide, polyphenylene oxide, polyetherimide), alcohol-based polymers (polyvinyl alcohol, polybutyl alcohol, polyalkylene glycol) and the like. The hydrophilic polymer (D) may be used alone or in combination of two or more. From the viewpoint of input / output and cycle characteristics, the amount of the hydrophilic polymer (D) is preferably 0.01 to 30% by mass, more preferably 0.1 to 10% by mass with respect to the active material before coating. is there.

  In addition to the resin composition (C), the resin-coated active material may have a rubber-based polymer (E) on at least a part of the active material surface. Rubber polymers (E) include natural rubber, styrene / butadiene rubber, isoprene rubber, nitrile rubber, chloroprene rubber, butyl rubber, ethylene / propylene rubber, acrylic rubber, chlorinated polyethylene rubber, fluorine rubber, silicone rubber, urethane rubber. , Polysulfide rubber, styrene / isoprene / styrene rubber, acrylonitrile / butadiene rubber, butadiene rubber, ethylene / propylene / diene copolymer, etc., among which natural rubber, styrene / butadiene rubber, isoprene rubber, ethylene Propylene rubber, styrene / isoprene / styrene rubber and acrylonitrile / butadiene rubber are preferred, and natural rubber, styrene / butadiene rubber and ethylene / propylene rubber are particularly preferred from the viewpoint of viscoelasticity. The rubber polymer (E) may be used alone or in combination of two or more. In terms of input / output, electrode strength, and cycle characteristics, the amount of the rubber-based polymer (E) is preferably 0.01 to 30% by mass, more preferably 0.1 to 10% with respect to the active material before coating. % By mass.

  In addition to the resin composition (C), the resin-coated active material may have a conductive additive (F) on at least a part of the active material surface. As the conductive assistant (F), vapor grown carbon fiber (VGCF), carbon nanotube, carbon nanofiber, graphite, carbon black, Cu, Ni, Si, or an alloy powder thereof (preferably an average particle diameter of 10 μm or less) ) And the like. A conductive support agent (F) may be individual, or may use 2 or more types together. From the viewpoint of cycle characteristics, the amount of the conductive auxiliary agent (F) is preferably 0.01 to 30% by mass, more preferably 0.1 to 10% by mass with respect to the active material before coating.

  A resin-coated active material having at least one of a hydrophilic polymer (D), a rubber-based polymer (E), and a conductive additive (F) on at least a part of the surface of the active material is added to the resin composition (C). After blending the desired components of the above (D) to (F), it can be obtained by repeating the step of mixing with an active material in an aqueous solvent and then drying, one or more times. Moreover, it obtains by repeating the process of mixing the desired component and active material among the resin composition (C) and said (D)-(F), and then drying in an aqueous solvent once or more. You can also. The selection of the desired component may be arbitrarily changed in each step repeatedly performed. For example, after the step of blending the resin composition (C) with the above (D) and coating the active material, the resin composition (C) is blended with the above (F) to coat the active material. You may perform a process and also perform the process coat | covered with the resin composition (C). Alternatively, after the step of coating the active material with the resin composition (C), and then the step of coating the active material with the resin composition (C) blended with the above (F), the resin composition (C) In addition, the step of coating the active material by blending the above (E) may be performed. Then, you may perform the process of mix | blending said (D) with a resin composition (C), and coat | covering an active material.

  For a resin-coated active material having at least one of a hydrophilic polymer (D), a rubber-based polymer (E), and a conductive additive (F) on at least a part of the active material surface, a resin composition ( The coating ratio of a desired component among C) and (D) to (F) is preferably 0.01% or more with respect to the entire surface of the active material from the viewpoint of input / output, electrode strength, and cycle characteristics. More preferably, it is 0.1% or more.

An electrode can be obtained by forming an active material layer on a current collector using the above resin-coated active material. The method for producing the electrode is not particularly limited. For example, a resin-coated active material, if necessary, a conductive additive, a binder or the like are mixed in a dry form to form a sheet, and this is pressure-bonded to a current collector, or a resin-coated active material. Examples include a method of adding a solvent to a substance, and optionally a conductive additive, a thickener, a binder, etc. to form a slurry, which is applied to a substrate of a current collector, and dried. In addition, you may use a resin coating active material and another active material together in the range which does not impair the effect of this invention. Since the resin-coated active material is excellent in dispersibility in water, it is suitable for producing an electrode as a slurry using an aqueous solvent.
Here, using an active material not coated with resin or the like, a binder and a solvent are added and mixed. Further, the alkali metal salt (B) in the present invention (in some cases, a hydrophilic polymer (D), a rubber-based polymer) The active material layer (electrode) produced by the slurry to which the molecule (E) and the conductive auxiliary agent (F) are added differs from the active material layer by the resin-coated active material of the present invention in terms of structure, effect, and adjustment method. . This is because the resin composition (C) of the resin-coated active material of the present invention contains a cellulosic polymer or a metal salt thereof (A), which is usually a gel in water (a jelly that dissolves slowly in water). In order to form a (state), even if it passes through the slurry preparation process stirred and mixed with a binder and arbitrary thickeners, it hardly peels off from the active material surface or dissolves. For this reason, the alkali metal salt (B) (possibly hydrophilic polymer (D), rubber polymer (E), conductive auxiliary agent (F)) of the resin-coated active material is also peeled off in the slurry preparation step. And dissolution is suppressed, and a large amount can be present in the vicinity of the active material surface. Furthermore, in the step of applying the slurry, it does not remain on the surface of the current collector or the binder, and when the battery is produced, it does not diffuse into the electrolytic solution and cause side reactions on the positive electrode. As a result, the resin-coated active material of the present invention can exhibit high input / output characteristics and cycle characteristics. Therefore, it can be said that the present invention is clearly technically different from the usage method in which the resin composition (C) is added in the slurry preparation step.

  Hereinafter, although the case where the negative electrode of a lithium ion secondary battery is prepared will be described as an example, the resin-coated active material of the present invention can also be used for the preparation of a positive electrode.

<Negative electrode>
The material of the negative electrode current collector is not particularly limited, and examples thereof include metal materials such as copper, nickel, stainless steel, and nickel-plated steel, and carbon materials such as carbon cloth and carbon paper. Among these, a metal material is preferable, and copper is more preferable.

  The shape of the negative electrode current collector is not particularly limited, and examples thereof include a thin film shape, a columnar shape, and a plate shape. In the case of a thin film, the thickness is not particularly limited, and is usually 5 to 30 μm. The thickness is preferably 9 μm or more, and preferably 20 μm or less. Among these, a metal thin film is preferable, and copper foil is particularly preferable. The thin film can be appropriately meshed.

  The amount of the negative electrode active material is usually 70 to 99.99% by mass in the negative electrode active material layer. The amount is preferably 75% by mass or more, more preferably 80% by mass or more, and preferably 99.9% by mass or less. Although a resin-coated active material is used as the negative electrode active material, other known negative electrode active materials may be used as long as the effects of the present invention are not impaired.

  The binder is not particularly limited as long as it can bind the negative electrode active material, and is a resin-based polymer such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene Butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, rubber polymer such as ethylene propylene rubber; styrene butadiene styrene block copolymer or hydrogenated product thereof, EPDM (ethylene・ Propylene / diene terpolymers, styrene / ethylene / butadiene / ethylene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; thermoplastic elastomer polymers; syndiotactic Soft resin polymers such as 1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride (PVDF), polytetrafluoroethylene, fluorinated poly Fluorine polymers such as vinylidene fluoride and polytetrafluoroethylene / ethylene copolymer; polymer compositions having ion conductivity of alkali metal ions (especially lithium ions), among which the weight average molecular weight is 10,000- 3 million can be used. The weight average molecular weight is preferably 100,000 or more, and preferably 1,000,000 or less. Here, the weight average molecular weight is a value determined by gel permeation chromatography (polystyrene conversion). A binder may be individual or may use 2 or more types together.

  The amount of the binder is not particularly limited, and is generally 0.05 to 20% by mass with respect to the negative electrode active material, from the viewpoint of securing battery performance such as retention and mechanical strength of the negative electrode active material, and cycle characteristics. Preferably it is 0.1-10 mass%, More preferably, it is 0.5-5 mass%.

  When the negative electrode active material layer is formed using the slurry, the solvent is not particularly limited as long as it can dissolve or disperse the negative electrode active material and the like, and either an aqueous solvent or an organic solvent is used. be able to. Since the resin-coated active material is excellent in dispersibility in water, it is suitable for preparing a negative electrode as a slurry using an aqueous solvent. Aqueous solvents are also preferred from the viewpoint of reducing environmental burden.

  Examples of the aqueous solvent include water, alcohol (for example, lower alcohol such as ethanol), and examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, acrylic acid. Methyl, diethyltriamine, N, N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethylacetamide, hexamethylphosphamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methyl Naphthalene, hexane, etc. are mentioned. A solvent may be individual or may use 2 or more types together.

  In particular, when an aqueous solvent is used, it is preferable to use a thickener together. In particular, it is preferable to use a thickener in combination with a rubber-based polymer such as SBR. The thickener is not particularly limited, and examples thereof include water-soluble cellulose polymers such as carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, and ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and metal salts thereof. Thickeners may be used alone or in combination of two or more.

  When using a thickener, the amount ensures good coatability, keeps the proportion of the active material in the negative electrode active material layer properly, reduces the battery capacity, and reduces the electric resistance between the negative electrode active materials. In order to avoid the problem of increasing, it is usually 0.05 to 20% by mass, preferably 0.1 to 10% by mass, more preferably 0.5 to 5% by mass, based on the negative electrode active material. It is.

  After apply | coating a slurry on a collector, it can dry in dry air or inert atmosphere, a negative electrode active material layer can be formed, and a negative electrode can be obtained. The drying temperature is 60 ° C to 200 ° C, preferably 80 ° C or higher, and preferably 195 ° C or lower.

  The thickness of the negative electrode active material layer is usually 5 to 200 μm in order to ensure practicality as a negative electrode and sufficient lithium occlusion / release function for high-density current values. The thickness is preferably 20 μm or more, more preferably 30 μm or more, and preferably 100 μm or less, more preferably 75 μm or less.

  The present invention also relates to a lithium ion secondary battery including the negative electrode. The basic structure of a lithium ion secondary battery is the same as that of a well-known thing, Usually, the positive electrode and electrolyte which can occlude / release lithium ion other than the said negative electrode are provided.

<Positive electrode>
As the positive electrode, one in which an active material layer containing a positive electrode active material is usually formed on a current collector is used. The method for producing the positive electrode is not particularly limited. For example, a positive electrode active material, a binder, and the like are mixed in a dry form to form a sheet, which is pressure-bonded to the positive electrode current collector, a positive electrode active material, a binder, and the like with a solvent. In addition, a method of forming a slurry, applying this to a substrate of a positive electrode current collector, and drying the slurry can be mentioned.

  The material of the positive electrode current collector is not particularly limited, and examples thereof include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum, and carbon materials such as carbon cloth and carbon paper. Among these, a metal material is preferable, and aluminum is more preferable.

  The shape of the positive electrode current collector is not particularly limited, and examples thereof include a thin film shape, a columnar shape, and a plate shape. In the case of a thin film, the thickness is not particularly limited, and is usually 1 μm to 100 mm from the viewpoint of strength required for a positive electrode current collector and handleability. The thickness is preferably 3 μm or more, more preferably 5 μm or more, and preferably 1 mm or less, more preferably 50 μm or less. Among these, a metal thin film is preferable, and can be appropriately meshed.

The positive electrode active material is not particularly limited as long as it is a material that can occlude and release lithium ions during charge and discharge, and examples thereof include metal chalcogen compounds. Examples of metal chalcogen compounds include vanadium oxide, molybdenum oxide, manganese oxide, chromium oxide, titanium oxide, tungsten oxide and other transition metal oxides, vanadium sulfide, molybdenum sulfide. , Transition metal sulfides such as CuS, transition metal sulfides such as NiPS ₃ and FePS ₃ , selenium compounds of transition metals such as VSe ₂ and NbSe ₃ , Fe _0.25 V _0. Examples thereof include composite oxides of transition metals such as ₇₅ S ₂ and Na _0.1 CrS ₂ and composite sulfides of transition metals such as LiCoS ₂ and LiNiS ₂ . Among them, V ₂ O ₅ , V ₅ O ₁₃ , VO ₂ , Cr ₂ O ₅ , MnO ₂ , TiO, MoV ₂ O ₈ , LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , TiS ₂ , V ₂ S ₅ , Cr _0.25 V _0.75 S ₂ , Cr _0.5 V _0.5 S _{2 and the} like are preferable, and LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , and a part of these transition metals are preferably used as other metals. Lithium transition metal composite oxide substituted with The positive electrode active material may be used alone or in combination of two or more.

  The amount of the positive electrode active material is usually 10 to 99.9% by mass in the positive electrode active material layer. The amount is preferably 30% by mass or more, more preferably 50% by mass or more, and preferably 99% by mass or less.

  The binder is not particularly limited as long as it can bind the positive electrode active material. Resin-based polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose; SBR (styrene Butadiene rubber), NBR (acrylonitrile butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, rubber polymer such as ethylene propylene rubber; styrene butadiene styrene block copolymer or hydrogenated product thereof, EPDM (ethylene・ Propylene / diene terpolymers, styrene / ethylene / butadiene / ethylene copolymers, styrene / isoprene / styrene block copolymers or hydrogenated products thereof; thermoplastic elastomer polymers; syndiotactic Soft resin polymers such as 1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride (PVDF), polytetrafluoroethylene, fluorinated poly Fluorine polymers such as vinylidene fluoride and polytetrafluoroethylene / ethylene copolymer; polymer compositions having ion conductivity of alkali metal ions (especially lithium ions), among which the weight average molecular weight is 10,000- 3 million can be used. The weight average molecular weight is preferably 100,000 or more, and preferably 1,000,000 or less. Here, the weight average molecular weight is a value determined by gel permeation chromatography (polystyrene conversion). A binder may be individual or may use 2 or more types together.

  The amount of the binder is not particularly limited, and is generally 0.1 to 80 mass in the positive electrode active material from the viewpoint of securing the positive electrode active material and mechanical strength, and battery performance such as cycle characteristics, capacity, and conductivity. %. The amount is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 60% by mass or less, more preferably 40% by mass or less, and particularly preferably 10% by mass or less.

  In order to improve the conductivity of the positive electrode, the positive electrode active material layer can contain a conductive material. The conductive material is not particularly limited, and examples thereof include carbon powder such as acetylene black, carbon black, and graphite, metal fiber, metal powder, and metal foil. The conductive material may be used alone or in combination of two or more.

  When the positive electrode active material layer is formed using the slurry, the solvent is not particularly limited as long as the positive electrode active material or the like can be dissolved or dispersed, and either an aqueous solvent or an organic solvent is used. be able to. Aqueous solvents are preferred from the viewpoint of reducing environmental burden.

  Examples of the aqueous solvent include water, alcohol (for example, ethanol), and examples of the organic solvent include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N, N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethylacetamide, hexamethylphosphalamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, etc. Can be mentioned. A solvent may be individual or may use 2 or more types together.

  In particular, when an aqueous solvent is used, it is preferable to use a thickener together. In particular, it is preferable to use a thickener in combination with a rubber-based polymer such as SBR. The thickener is not particularly limited, and examples thereof include water-soluble cellulose polymers such as carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, and ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. Thickeners may be used alone or in combination of two or more.

  When using a thickener, the amount ensures good coatability, keeps the proportion of the active material in the positive electrode active material layer appropriate, reduces the battery capacity, and reduces the resistance between the positive electrode active materials. In order to avoid the problem of increasing, it is usually 0.1 to 5% by mass in the positive electrode active material layer. The amount is preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and preferably 3% by mass or less, more preferably 2% by mass or less.

  The thickness of the positive electrode active material layer is usually 10 to 200 μm. The positive electrode active material layer obtained by applying the slurry to the positive electrode current collector and drying is preferably consolidated by a roller press or the like in order to increase the packing density of the positive electrode active material.

<Electrolyte>
As the electrolyte, a nonaqueous electrolytic solution in which a lithium salt is dissolved in a nonaqueous solvent, a gel electrolyte, a rubber electrolyte, a solid sheet electrolyte, or the like is usually used.

  The non-aqueous solvent used for the non-aqueous electrolyte is not particularly limited, and a non-aqueous solvent known in the art can be used. For example, chain carbonates such as diethyl carbonate, dimethyl carbonate and ethyl methyl carbonate; cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; chain ethers such as 1,2-dimethoxyethane; tetrahydrofuran, 2-methyl Examples include cyclic ethers such as tetrahydrofuran, sulfolane and 1,3-dioxolane; chain esters such as methyl formate, methyl acetate and methyl propionate; cyclic esters such as γ-butyrolactone and γ-valerolactone. These non-aqueous solvents may be used alone or in combination of two or more. Among these, a mixed solvent containing a cyclic carbonate and a chain carbonate is preferable.

The lithium salt used for the non-aqueous electrolyte is not particularly limited, and a lithium salt known in the art can be used. For example, halides such as LiCl and LiBr, perhalogenates such as LiClO ₄ , LiBrO ₄ and LiClO ₄ , inorganic fluoride salts such as LiPF ₆ , LiBF ₄ and LiAsF ₆ , lithium bis (oxalatoborate) LiBC ₄ O Inorganic lithium salts such as ₈ , perfluoroalkanesulfonic acid salts such as LiCF ₃ SO ₃ and LiC ₄ F ₉ SO ₃ , and perfluoroalkanesulfonic acid imides such as lithium trifluorosulfonimide ((CF ₃ SO ₂ ) ₂ NLi) Examples thereof include fluorine-containing organic lithium salts such as salts. Lithium salts may be used alone or in combination of two or more. The concentration of the lithium salt in the non-aqueous electrolyte is usually 0.5M or more and 2.0M or less.

  The non-aqueous electrolyte solution may contain an organic polymer compound to form a gel electrolyte, rubber electrolyte, or solid sheet electrolyte. In this case, examples of the organic polymer compound include polyether polymer compounds such as polyethylene oxide and polypropylene oxide; crosslinked polymers of polyether polymer compounds; vinyl alcohol polymer compounds such as polyvinyl alcohol and polyvinyl butyral; vinyl Insoluble matter of alcohol polymer compound; polyepichlorohydrin; polyphosphazene; polysiloxane; vinyl polymer compound such as polyvinylpyrrolidone, polyvinylidene carbonate, polyacrylonitrile; poly (ω-methoxyoligooxyethylene methacrylate), poly (ω -Methoxyoligooxyethylene methacrylate-co-methyl methacrylate), polymers such as poly (hexafluoropropylene-vinylidene fluoride), and the like.

  The non-aqueous electrolyte can further contain a film forming agent. As the film forming agent, vinylene carbonate, vinyl ethylene carbonate, vinyl ethyl carbonate, methyl phenyl carbonate, fluoroethylene carbonate, difluoroethylene carbonate and other carbonate compounds, ethylene sulfide, propylene sulfide and other alkene sulfides; 1,3-propane sultone, Examples include sultone compounds such as 1,4-butane sultone; acid anhydrides such as maleic anhydride and succinic anhydride.

  When a film forming agent is used, the amount thereof is usually 10% by mass or less, preferably 8% from the viewpoint of securing an appropriate initial irreversible capacity and avoiding deterioration of battery characteristics such as low temperature characteristics and rate characteristics. It is 5% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

  As the electrolyte, a polymer solid electrolyte that is a conductor of an alkali metal cation such as lithium ion can also be used. Examples of the polymer solid electrolyte include those obtained by dissolving a lithium salt in the aforementioned polyether polymer compound, and polymers in which the terminal hydroxyl group of the polyether is substituted with an alkoxide.

<Separator>
Usually, a separator is interposed between the positive electrode and the negative electrode in order to prevent a short circuit. A non-aqueous electrolyte is usually used by impregnating this separator. The material of the separator is not particularly limited, and materials known in the art can be used. Examples thereof include polyolefins such as polyethylene and polypropylene, polyethersulfone, and the like, preferably polyolefin.

  In the present invention, the form of the lithium ion secondary battery is not particularly limited, and may be a form known in the art. For example, a cylinder type in which a sheet electrode and a separator are spirally formed, a cylinder type having an inside-out structure in which a pellet electrode and a separator are combined, a coin type in which a pellet electrode and a separator are stacked, and the like can be given. In addition, by storing batteries of these forms in an optional outer case, the battery can be used in an arbitrary shape such as a coin shape, a cylindrical shape, or a square shape.

  In the present invention, the procedure for assembling the lithium ion secondary battery is not particularly limited, and can be assembled by an appropriate procedure according to the structure of the battery. For example, a negative electrode can be placed on an outer case, an electrolyte and a separator can be provided thereon, and a positive electrode can be placed so as to face the negative electrode, and can be caulked together with a gasket and a sealing plate to form a battery.

  Next, specific embodiments of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

(Manufacture of negative electrode active material)
Naturally produced graphite with a 002 plane spacing (d002) of 3.36 mm by L-ray wide angle diffraction method, Lc of 1000 mm or more, tap density of 0.46 g / cm ³ , and 1580 cm ⁻¹ in an argon ion laser Raman spectrum. The scale-like graphite particles having a Raman R value which is a peak intensity ratio around 1360 cm ^{−1 to} a peak intensity around 0.13, an average particle diameter of 28.7 μm and a true density of 2.27 g / cm ³ are Damage to the graphite particle surface by continuously processing the scaly graphite particles at a processing speed of 20 kg / hr under conditions of a rotor peripheral speed of 60 m / second and 10 minutes using a machine system manufactured by Kikai Seisakusho. The spheroidization treatment was performed while fine powder was removed by further classification treatment. The obtained spheroidized graphitic carbon has an 002 plane spacing (d002) of 3.36 mm, an Lc of 1000 mm or more, a tap density of 0.83 g / cm ³ by an X-ray wide angle diffraction method, and an argon ion laser Raman spectrum. 1580 cm ^-1 Raman R value is the peak intensity ratio in the vicinity of 1360 cm ^-1 to the peak intensity near 0.24, an average particle diameter of 11.6, BET method specific surface area of 7.7 m ² / g, a true density of 2.27 g / cm ³ and the average circularity was 0.909.
Next, 100 parts by mass of this spheroidized graphitic carbon and 9.4 parts by mass of coal-derived pitch are mixed by heating at 160 ° C. in a compounding machine, and then baked to 1000 ° C. over 2 weeks in a non-oxidizing atmosphere. By cooling to room temperature and further performing pulverization and classification, a multi-layer structure spheroidized carbon material was obtained. This multi-layered spheroidized carbon material has a 002 plane spacing (d002) of 3.36 mm, an Lc of 1000 mm or more, a tap density of 0.98 g / cm ³ by an X-ray wide angle diffraction method, and an argon ion laser Raman spectrum of 1580 cm. ^The Raman R value, which is the peak intensity ratio near 1360 cm ^{−1 to} the peak intensity near ⁻¹ , is 0.31, the average particle size is 11.6 μm, the d10 particle size is 7.6 μm, the d90 particle size is 17.5 μm, and the BET specific surface area Is 3.5 m ² / g, the coverage is 5.0%, and the ratio of rhombohedral 3R to hexagonal 2H by the X-ray wide angle diffraction method is 3R / 2H of 0.26, 10 nm to 100,000 nm. Was 0.74 ml / g. In addition, the pitch derived from coal used alone was fired in a nitrogen atmosphere to 1300 ° C., then cooled to room temperature, and pulverized to obtain a 002 surface by an X-ray wide angle diffraction method of an amorphous carbon single material. The surface separation (d002) was 3.45 mm and Lc was 24 mm.

(Production of resin-coated active material)
By adding and mixing 0.05 g of NaCl to 0.95 g of carboxymethyl cellulose (degree of polymerization: 1000, degree of etherification: 0.8, pure content: 99.4 mass%), 95 mass% of carboxymethyl cellulose is contained, and A resin composition containing 5% by mass of NaCl (a ratio of Na derived from NaCl to 4% by mass with respect to 100% by mass of the resin composition: ICP-MS analysis (inductively coupled plasma mass measurement apparatus)) was prepared.
1 g of the obtained resin composition and 99 g of the negative electrode active material were mixed in ultrapure water, and then dried at 110 ° C. in nitrogen gas to obtain a resin-coated negative electrode active material. The coverage of the active material with the resin composition was 10%.

(Preparation of negative electrode)
100 g of the above resin-coated negative electrode active material, 100 g of an aqueous solution (concentration: 1% by mass) of carboxymethyl cellulose as a thickener, an aqueous dispersion of styrene-butadiene rubber (unsaturation: 75%, weight average molecular weight: 120,000) 2 g) (solid content concentration 50% by weight) was mixed using a high speed mixer to form a slurry. This slurry was applied onto a copper foil (current collector) by a doctor blade method and dried at 110 ° C. This was pressed at a linear density of 20 to 300 kg / cm by a roll press to form an active material layer. The mass of the active material layer after drying was 10 mg / cm ² , the density was 1.6 g / cm ³ , and the average electrode thickness was 68 μm. The negative electrode (negative electrode for lithium ion secondary battery) produced by the above procedure was used as the negative electrode of Example 1.

  The negative electrode of Example 2 was prepared in the same manner as in Example 1 except that the resin composition (NaCl 50% by mass) was prepared with 0.5 g of carboxymethyl cellulose and 0.5 g of NaCl at the time of preparing the resin-coated active material. Was made. The coating ratio of the active material with the resin composition was 1%.

  Except that 0.5 g of the resin composition, 99 g of the negative electrode active material, and 0.5 g of polyacrylamide (weight average molecular weight: 5 million) as a hydrophilic polymer were mixed in ultrapure water during the production of the resin-coated active material. In the same manner as in Example 1, a negative electrode of Example 3 was produced. The coating ratio of the active material with the resin composition and polyacrylamide was 12%.

  When preparing the resin-coated active material, 0.5 g of the resin composition, 99 g of the negative electrode active material, and an aqueous dispersion of styrene-butadiene rubber (unsaturation: 75%, weight average molecular weight: 120,000) as a rubber polymer ( A negative electrode of Example 4 was produced in the same manner as in Example 1 except that 1 g of a solid content concentration of 50% by weight was mixed in ultrapure water. The coverage of the active material with the resin composition and styrene-butadiene rubber was 18%.

  In the same manner as in Example 1, except that 0.5 g of the resin composition, 99 g of the negative electrode active material, and 0.5 g of VGCF as a conductive auxiliary agent were mixed in ultrapure water when the resin-coated active material was prepared. 5 negative electrode was produced.

  At the time of preparing the resin-coated active material, after coating with a resin composition containing 95% by mass of carboxymethyl cellulose and 5% by mass of NaCl, polyacrylamide (weight average molecular weight: 5 million) is further added as a hydrophilic polymer. Example 1 except that it was coated with 1 g of an aqueous dispersion (solid content concentration: 50 wt%) of styrene / butadiene rubber (unsaturation degree: 75%, weight average molecular weight: 120,000) as a rubber polymer. Similarly, the negative electrode of Example 6 was produced. The coverage of the active material with the resin composition, polyacrylamide, and styrene-butadiene rubber was 20%.

  A negative electrode of Comparative Example 1 was prepared in the same manner as in Example 1 except that a negative electrode active material not coated with a resin was used instead of the resin-coated active material in the preparation of the slurry for preparing the negative electrode. .

  In the preparation of the slurry for preparing the negative electrode, 99 g of the negative electrode active material not coated with resin, 100 g of an aqueous solution of carboxymethyl cellulose (concentration: 1% by mass), styrene-butadiene rubber (unsaturation: 75%, weight average molecular weight: Comparative Example 2 in the same manner as in Example 1, except that 2 g of 120,000) aqueous dispersion (solid content concentration 50% by weight) and 1 g of the resin composition of Example 1 (NaCl 5% by mass) were used. A negative electrode was prepared.

(Production of battery for performance evaluation)
To 100 parts by mass of LiCoO _2, 10 parts by mass of a 50% by mass aqueous dispersion of polytetrafluoroethylene, 40 parts by mass of a 1% by mass aqueous solution of carboxymethyl cellulose, and 3 parts by mass of carbon black were added and kneaded to obtain a slurry. This slurry was applied to both surfaces of the aluminum foil by a doctor blade method and dried at 110 ° C. Furthermore, it compacted with the roll press so that the density of a layer might be set to 3.5 g / cm < ³ >. Subsequently, it was dried at 140 ° C. to obtain a positive electrode. An electrolyte solution prepared by mixing 1% by mass of vinylene carbonate and 0.8M LiPF ₆ in a 2: 3: 5 (volume ratio) mixture of propylene carbonate: ethylene carbonate: diethylene carbonate was prepared, and polyethylene The separator was impregnated.
The negative electrodes of Examples and Comparative Examples were stacked on both surfaces of the positive electrode via a separator impregnated with an electrolytic solution to obtain an evaluation battery.

(Evaluation of low temperature output characteristics)
The battery for evaluation produced as described above was charged at a constant current of 0.2 C for 150 minutes in a 25 ° C. environment, and then stored in a thermostatic bath at −30 ° C. for 3 hours or more. It was discharged for 2 seconds at .50 C, 0.75 C, 1.00 C, 1.25 C, 1.50 C, 1.75 C, and 2.00 C, and the voltage at the second second was measured. The area of the triangle surrounded by the current-voltage line and the lower limit voltage (3 V) was defined as output (W). The results are shown in Table 1.

(Evaluation of cycle maintenance rate)
The evaluation battery produced as described above was charged to 4.2 V at 0.2 C, charged to 4.2 mA at 4.2 V, and then precharged / discharged to 3.0 V at 0.2 C. It was. Next, the battery was charged to 0.7 V at 0.7 C, charged to 4.2 mA at 4.2 V, and then subjected to 300 cycles of charge / discharge to discharge to 3.0 V at 1 C. The ratio of the 500th discharge capacity to the first discharge capacity was determined, and this was used as the cycle retention rate. The results are shown in Table 1.

From the results in Table 1, the following is clear.
Compared to Comparative Example 1 using a negative electrode active material not coated with resin, the batteries of Examples 1 to 6 using a resin-coated active material have improved low-temperature output characteristics and maintained good cycle characteristics. You can see that
On the other hand, from comparison between Examples 1 to 6 and Comparative Example 2, it is more excellent in low temperature output characteristics and cycle characteristics when the active material is coated than when the resin composition (C) is added and mixed during slurry adjustment. I understand. In particular, it can be seen that Examples 3 to 6 coated with polyacrylamide, styrene-butadiene rubber and VGCF are remarkably improved. Therefore, it can be said that only the resin-coated active material for the non-aqueous secondary battery electrode of the present invention, particularly for the lithium ion secondary battery electrode, achieves both low temperature output and cycle characteristics at a high level.

  When the resin-coated active material of the present invention is used for an electrode of a non-aqueous secondary battery, particularly a lithium ion secondary battery, the input / output characteristics and cycle characteristics at low temperatures can be improved in a balanced manner. The electrode using the resin-coated active material of the present invention can be prepared with an aqueous solvent and has a low environmental load.

Claims (11)

  Cellulosic polymer or resin composition (C) containing metal salt (A) and alkali metal salt (B) (however, alkali metal salt (B) is not an alkali metal salt of cellulosic polymer) ) Covers at least a part of the surface of the active material, a resin-coated active material for a non-aqueous secondary battery electrode.   The resin-coated active material for a non-aqueous secondary battery electrode according to claim 1, wherein the alkali metal salt (B) is 1% by mass or more with respect to 100% by mass of the resin composition (C).   The resin coating for a non-aqueous secondary battery electrode according to claim 1 or 2, which is obtained by repeating the step of drying after mixing the resin composition (C) and the active material in an aqueous solvent one or more times. Active material.   The resin coating for a nonaqueous secondary battery electrode according to any one of claims 1 to 3, wherein the alkali metal salt (B) is at least one selected from the group consisting of an organic salt, an inorganic salt, and a complex salt. Active material.   The nonaqueous system according to any one of claims 1 to 4, further comprising a hydrophilic polymer (D) (provided that it is not a cellulosic polymer) on at least a part of the surface of the active material. Resin-coated active material for secondary battery electrodes.   Furthermore, the resin coating active material for non-aqueous secondary battery electrodes of any one of Claims 1-5 which has a rubber-type polymer (E) in at least one part of the surface of an active material.   Furthermore, the resin coating active material for non-aqueous secondary battery electrodes of any one of Claims 1-6 which has a conductive support agent (F) in at least one part of the surface of an active material.   The resin-coated active material for a non-aqueous secondary battery electrode according to any one of claims 1 to 7, wherein an active material capable of inserting and extracting lithium ions is used.   The electrode for non-aqueous secondary batteries provided with the active material layer containing the resin coating active material of any one of Claims 1-8 on a collector.   The negative electrode for a non-aqueous secondary battery according to claim 9, wherein the active material layer is a negative electrode active material layer and further contains a thickener and a rubber polymer.   A nonaqueous secondary battery comprising the negative electrode according to claim 10, a positive electrode, and an electrolyte.