CN104584288A - Binder for nonaqueous electrolyte secondary cell, binder solution for nonaqueous electrolyte secondary cell, anode mixture for nonaqueous electrolyte secondary cell, and uses thereof - Google Patents

Binder for nonaqueous electrolyte secondary cell, binder solution for nonaqueous electrolyte secondary cell, anode mixture for nonaqueous electrolyte secondary cell, and uses thereof Download PDF

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Publication number
CN104584288A
CN104584288A CN201380043612.2A CN201380043612A CN104584288A CN 104584288 A CN104584288 A CN 104584288A CN 201380043612 A CN201380043612 A CN 201380043612A CN 104584288 A CN104584288 A CN 104584288A
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electrolyte secondary
nonaqueous electrolyte
vinylidene fluoride
polyvinyl alcohol
functional group
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CN201380043612.2A
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CN104584288B (en
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冈田佳余子
小林正太
多田靖浩
园部直弘
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Kureha Corp
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Kureha Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H01M4/623—Binders being polymers fluorinated polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The present invention relates to a binder for a nonaqueous electrolyte secondary cell, a binder solution for the nonaqueous electrolyte secondary cell, and an anode mixture for the nonaqueous electrolyte secondary cell having excellent adhesiveness, allowing reduction of initial irreversible capacity of the nonaqueous electrolyte secondary cell when manufacturing the cell, having an excellent capacity retention rate during fast discharge, and allowing improvement of charge cycle characteristics, this binder for a nonaqueous electrolyte secondary cell including at least a functional-group-containing vinylidene fluoride polymer and a polyvinyl alcohol having saponification of 35-90 mol percent, the polyvinyl alcohol being 5-93 mass percent per the total 100 mass percent of the functional-group-containing vinylidene fluoride polymer and the polyvinyl alcohol.

Description

Rechargeable nonaqueous electrolytic battery adhesive, rechargeable nonaqueous electrolytic battery binder solution, anode for nonaqueous electrolyte secondary battery mixture and uses thereof
Technical field
The present invention relates to a kind of rechargeable nonaqueous electrolytic battery adhesive, rechargeable nonaqueous electrolytic battery binder solution, anode for nonaqueous electrolyte secondary battery mixture and uses thereof.
Background technology
Electronic technology development is in recent years advanced by leaps and bounds, and the multifunction of small portable apparatus is developed, and needs the power supply of these equipment use to realize miniaturized and lightweight (high-energy-density).As the battery with high-energy-density, with lithium rechargeable battery etc. for the rechargeable nonaqueous electrolytic battery of representative is widely used.In recent years along with the development of small portable apparatus multifunction, the lifting etc. of the further high-energy-density of rechargeable nonaqueous electrolytic battery and durability enjoys expectation.
On the other hand, from the view point of global environmental problems and energy-conservation, the hybrid vehicle that secondary cell and engine combine, to be developed using secondary cell as the electric automobile etc. of power supply, and it is practically developed.
As the power supply of hybrid vehicle and electric automobile etc. and the vehicle-mounted power supply used, compared with the secondary cell used as small portable apparatus power supply, large-scale and expensive, and as the main parts size of automobile, therefore be difficult in use change battery, it needs to have high-durability.In addition, area and the season of use automobile are varied, therefore need to have durability under high/low temperature and maintain performance.And, in order to reduce oil consumption in these automobiles, and braking energy during brake being stored in battery most important, therefore needing that there is excellent charging rapidly.The acceleration promoting automobile needs to have the ability released energy at short notice, namely needs high output density.In sum, vehicle-mounted rechargeable nonaqueous electrolytic battery, except the performance that small portable apparatus secondary cell needs, also needs to improve the various performances comprising fail safe.
For obtaining the rechargeable nonaqueous electrolytic battery with this characteristic, carry out various research and development for each component forming this battery.Rechargeable nonaqueous electrolytic battery is formed primarily of positive pole, negative pole, the barrier film separated by both positive and negative polarity and electrolyte.Positive pole and negative pole are formed respectively by being bonded on collector plate by powdered active agent, for the performance playing active material is used as battery performance, must improve the binder performance as these active material adhesives.
Past, as the adhesive resin of bonding non-aqueous electrolyte secondary cell negative electrode active material, owing to having excellent electrochemically stability, mechanical properties and pulp property etc., therefore uses polyvinylidene fluoride (PVDF) more.
After rechargeable nonaqueous electrolytic battery repeated charge, charge/discharge capacity reduces more few more preferred, and therefore the structure of active material still keeps stable after needing repeated charge.And it is most important that active material and active material or active material and collector plate still can bond after Long-Time Service by adhesive in the electrodes.Vehicle-mounted large secondary battery, compared with small portable apparatus secondary cell, needs to have high-durability, also needs to improve the adhesiveness of adhesive for improving durability.
For improving adhesiveness, use a large amount of adhesive, but adhesive use amount increases, and can reduce the active matter quality in rechargeable nonaqueous electrolytic battery, cause the charge/discharge capacity of rechargeable nonaqueous electrolytic battery to reduce, therefore not preferred.
And, after the amount of binder used increases, a large amount of adhesive can cover the surface of active material, and in the vehicle-mounted secondary cell needing high input-output characteristic, the adhesive phase of active material surface becomes resistance components, become the reason causing input-output characteristic to reduce, therefore not preferred.
On the other hand, known to utilizing the reduction decomposition of electrolyte to form the surface coating being called as SEI (Solid Electrolyte Interface) film on negative electrode active material surface, the electrolyte decomposition on negative electrode active material surface can be suppressed, but there is following problem, if namely overlay film is thickening because of electrolyte excessive decomposition, then SEI overlay film becomes resistance components, causes capacity to reduce and input-output characteristic reduction.
Expect to there is a kind of adhesive resin, it does not increase amount of binder just can improve adhesiveness, and the epithelium of electrolyte excessive decomposition can be suppressed efficiently to cover negative terminal surface.
Past as all excellent adhesive resin composition of the adhesiveness of the adhesiveness of positive active material or negative electrode active material and collector body, active material and active material, its using (B) fluorinated resins such as (A) water-soluble resin and vinylidene fluoride resinoid such as polyvinyl alcohol derivatives as the adhesive resin composition of essential component by motion (such as referenced patent document 1).But the adhesiveness of the adhesive resin composition that patent documentation 1 is recorded is still insufficient.
In addition, as the lithium ion secondary battery anode that the uniformity of positive electrode material mixture layer, durability and productivity are all excellent, proposed a kind of lithium ion secondary battery anode, its positive electrode material mixture layer contains positive active material, electric conducting material and main binder i.e. the 1st macromolecule and the 2nd macromolecule (such as referenced patent document 2) that comprise lithium composite xoide.In patent documentation 2, polyvinylidene fluoride, vinylidene fluoride-chlorotrifluoroethylcopolymer copolymer, the maleic acid modified body of polyvinylidene fluoride and polytetrafluoroethylene can be exemplified out as the 1st macromolecule, polyvinyl alcohol, polyvinylpyrrolidone can be exemplified out as the 2nd macromolecule.Patent documentation 2 has been disclosed as to be guaranteed for the formation of the mobility of the anode mixture slurry of positive electrode material mixture layer and uses the 2nd macromolecule, and by using the 2nd macromolecule, in anode mixture slurry, the use amount of decentralized medium can not excessively increase.In addition, disclose the 2nd high molecular use amount and be preferably 0.01 ~ 3% relative to whole solid content, if more than 3%, then the rigidity of gained positive pole excessively increases, and may break when being wound around.
And, as long-life lithium secondary battery, proposed for suppress with charge and discharge cycles produce capacity and export reduce, and in adhesive principal component and thermosetting plasticization polyvinyl alcohol resin composition polyvinylidene fluoride used in combination (such as referenced patent document 3).But, only used with the polyvinyl alcohol of principal component and utilize succinyl oxide etc. to the thermosetting polyvinyl alcohol (first composition) of polyvinyl alcohol resin through modification.In addition, the synthetic reaction of this first composition is the esterification of polyvinyl alcohol, but for suppressing high viscosity and the gelation of reaction system, need to use a large amount of organic solvent, the moisture be difficult to existing in solvent manages, and therefore there is acid anhydrides and residual moisture reacts problems such as causing esterification yield reduction.And, also there is the problem that the unreacted reactant of ring-type anhydride and catalysts cause the aspect of performances such as degradation of cell performance.Further, also there is the problem because the reasons such as complex process cause manufacturing cost to become very high.
And in embodiment, the unexposed thermosetting polyvinyl alcohol resin that only relies on plays high performance example, and only exemplify out the embodiment of use crylic acid resin plasticizer as the second resinous principle, expression must add the second composition.In sum, also there is following problem points, namely the adhesive of manufacture principal component needs, through complicated operation, also to need the additives such as plasticizer, and implements these measures and need a large amount of operation.Further, on capacity dimension holdup and D.C. resistance (patent documentation 3, table 2), embodiment does not obtain effect excellent especially compared with comparative example, and more deep improvement becomes problem.
In addition, as the electrode binding agent that the confining force of the adhesion to electrode collector, active material is all excellent, motion goes out the agent of a kind of rechargeable nonaqueous electrolytic battery electrode binding, its contain with in polymer chain 30 ~ 95 % by weight ratio there is use-(CH 2-CHOH)-the vinyl alcohol polymer (such as referenced patent document 4) of construction unit that represents.As the agent of described rechargeable nonaqueous electrolytic battery electrode binding, openly can be used alone described vinyl alcohol polymer, also can use other electrode binding agent simultaneously, as the example of the adhesive that can use simultaneously, the openly fluorine resin such as polyvinylidene fluoride, polytetrafluoroethylene.
But vinyl alcohol polymer disclosed in patent documentation 4, as with-(CH 2-CHOH)-represent construction unit beyond construction unit, allow adopt various structure, use-(CH 2-CHOH)-represent construction unit beyond construction unit can on the physical property of rechargeable nonaqueous electrolytic battery cause which kind of impact not yet fully study.
In addition, the rechargeable nonaqueous electrolytic battery electrode binding agent using patent documentation 4 to record manufactures rechargeable nonaqueous electrolytic battery, capability retention sufficient battery when also not obtaining sudden discharge.
Prior art document
Patent documentation
Patent documentation 1: Japanese Patent Laid-Open 2004-95332 publication
Patent documentation 2: Japanese Patent Laid-Open 2009-123463 publication
Patent documentation 3: Japanese Patent Laid-Open 2004-134367 publication
Patent documentation 4: Japanese Patent Laid-Open 11-250915 publication
Brief summary of the invention
The problem that invention quasi-solution is determined
The problem exploitation existed in view of above-mentioned conventional art forms, the present invention relates to and a kind of rechargeable nonaqueous electrolytic battery adhesive, rechargeable nonaqueous electrolytic battery binder solution and anode for nonaqueous electrolyte secondary battery mixture are provided, it is when manufacturing rechargeable nonaqueous electrolytic battery, the initial irreversible capacity of this battery can be reduced, during sudden discharge, capability retention is excellent, charge/discharge cycle characteristics can be improved, and adhesiveness is excellent.
The means of dealing with problems
Present inventors etc. are the above-mentioned problem of solution, find after constantly studying with keen determination, by using the vinylidene fluoride polymer and specific polyvinyl alcohol that contain functional group with special ratios, can solve above-mentioned problem, and complete the present invention.
That is, it is at least the polyvinyl alcohol of 35 ~ 90mol% containing the vinylidene fluoride polymer of functional group and saponification degree that rechargeable nonaqueous electrolytic battery adhesive of the present invention comprises, and described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
The average degree of polymerization of described polyvinyl alcohol is preferably 100 ~ 4000.
Rechargeable nonaqueous electrolytic battery binder solution of the present invention is by described rechargeable nonaqueous electrolytic battery adhesive and solvent composition.
It is at least the polyvinyl alcohol of 35 ~ 90mol%, negative electrode active material and solvent containing the vinylidene fluoride polymer of functional group, saponification degree that anode for nonaqueous electrolyte secondary battery mixture of the present invention comprises, and described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
Described negative electrode active material is preferably made up of carbonaceous material.
Anode for nonaqueous electrolyte secondary battery of the present invention is coated with on the current collector by described anode for nonaqueous electrolyte secondary battery mixture, obtains after drying.
Rechargeable nonaqueous electrolytic battery of the present invention has described anode for nonaqueous electrolyte secondary battery.
Invention effect
The adhesiveness of rechargeable nonaqueous electrolytic battery adhesive of the present invention, rechargeable nonaqueous electrolytic battery binder solution, anode for nonaqueous electrolyte secondary battery mixture is excellent, if produce the rechargeable nonaqueous electrolytic battery with the anode for nonaqueous electrolyte secondary battery using these materials to be formed, then can reduce the initial irreversible capacity of this battery, during sudden discharge, capability retention is excellent, can improve charge/discharge cycle characteristics.
Embodiment
Below the present invention is specifically described.
Rechargeable nonaqueous electrolytic battery adhesive of the present invention, it is characterized in that, comprise is at least the polyvinyl alcohol of 35 ~ 90mol% containing the vinylidene fluoride polymer of functional group and saponification degree, and described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
Rechargeable nonaqueous electrolytic battery binder solution of the present invention is by described rechargeable nonaqueous electrolytic battery adhesive and solvent composition.
In addition, anode for nonaqueous electrolyte secondary battery mixture of the present invention, it is characterized in that, comprise is at least the polyvinyl alcohol of 35 ~ 90mol%, negative electrode active material and solvent containing the vinylidene fluoride polymer of functional group, saponification degree, and described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
In addition, in this specification, anode for nonaqueous electrolyte secondary battery mixture is only designated as cathode agent or mixture.
The vinylidene fluoride polymer containing functional group is used in the present invention.In the present invention, the vinylidene fluoride polymer containing functional group refers to, containing functional group in polymer, and the polymer being at least used as the vinylidene fluoride of monomer and obtaining.In addition, the vinylidene fluoride polymer containing functional group is the polymer by obtaining after common vinylidene fluoride, the monomer containing functional group and other monomers are as required carried out copolymerization.In addition, in the present invention, the monomer containing functional group in its molecule is denoted as the monomer containing functional group.
In addition, in the present invention, functional group refers to reactive high group, as the functional group in the present invention, is usually preferably polar group.In addition, the polar group in the present invention represents the atomic group containing atom beyond the carbon such as nitrogen, oxygen, sulphur, phosphorus and hydrogen.That is, the atom that fluorine, chlorine etc. are simple the polar group related in non-invention.
As the functional group contained by the vinylidene fluoride polymer containing functional group used in the present invention, carboxyl, epoxy radicals, carbonyl oxygen base, sulfo group, phosphonate group, acid anhydride and amino etc. can be exemplified.As functional group, from the viewpoint of the defluorinate acid reaction of the vinylidene fluoride polymer suppressed containing functional group, preferred acidic functional group.As acid functional groups, include, for example carboxyl (-CO 2h), sulfo group (-SO 3and phosphonate group (-PO H) 3h 2).As functional group, be preferably carboxyl, acid anhydride.The vinylidene fluoride polymer containing functional group used in the present invention contains at least a kind of these functional group, or also can contain two or more.As the vinylidene fluoride polymer containing functional group, from the viewpoint of bond properties and acquired, the vinylidene fluoride polymer preferably containing at least a kind of functional group selected in the group of free carboxyl group and acid anhydride's composition.
In addition, the vinylidene fluoride polymer containing functional group used in the present invention can be used alone a kind, also can use two or more.
The described vinylidene fluoride polymer containing functional group, in this polymer 100 mass parts, has more than construction unit 80 mass parts being derived from vinylidene fluoride usually, preferably more than 85 mass parts, below usual 99.9 mass parts, preferably below 99.7 mass parts.
The vinylidene fluoride polymer containing functional group used in the present invention usually by the following method in any one method make, namely vinylidene fluoride and the monomer containing functional group, other monomers are as required carried out the method (being also denoted as method (1) below) of copolymerization by (1); (2) vinylidene fluoride carried out be polymerized or obtain vinylidene fluoride polymer after vinylidene fluoride and other monomers are carried out copolymerization, monomer containing functional group carried out be polymerized or obtain the polymer containing functional group after the monomer containing functional group and other monomers are carried out copolymerization, this being contained the method (be below also denoted as method (2)) of polymer graft to this vinylidene fluoride polymer of functional group; And vinylidene fluoride carries out being polymerized or vinylidene fluoride and other monomers being carried out copolymerization by (3), and after obtaining vinylidene fluoride polymer, use the monomer containing functional group such as maleic acid or maleic anhydride this vinylidene fluoride polymer to be carried out the method (being denoted as method (3) below) of sex change.
Because the vinylidene fluoride polymer containing functional group used in the present invention has functional group, so compared with not having the polyvinylidene fluoride of functional group, be improved with the adhesiveness of collector body.
As the manufacture method of the vinylidene fluoride polymer containing functional group, in described method (1) ~ (3), from the viewpoint of process number and production cost, method (1) is preferably adopted to manufacture.
The vinylidene fluoride copolymer that the vinylidene fluoride polymer containing functional group used in the present invention obtains after being generally and vinylidene fluoride 80 ~ 99.9 mass parts and monomer 0.1 ~ 20 mass parts containing functional group (wherein the total of vinylidene fluoride and the monomer containing functional group being set to 100 mass parts) being carried out copolymerization.In addition, as the described vinylidene fluoride polymer containing functional group, can also be except described vinylidene fluoride and containing except the monomer of functional group, the polymer obtained after further other monomers being carried out copolymerization.In addition, when using other monomers, when described vinylidene fluoride and the total of monomer containing functional group are set to 100 mass parts, use other monomers common of 0.1 ~ 20 mass parts.
In addition, when manufacturing the vinylidene fluoride polymer containing at least a kind of functional group selected in the group of free carboxyl group and acid anhydride's composition, as the monomer containing functional group, the monomer of usual use containing at least a kind of functional group in the group selecting free carboxyl group and acid anhydride to form, preferably uses at least a kind of monomer in the group being selected from and being made up of the monomer containing carboxyl and the monomer containing acid anhydride.
When using at least a kind of monomer in the group being selected from and being made up of the monomer containing carboxyl and the monomer containing acid anhydride, vinylidene fluoride polymer containing functional group is preferably vinylidene fluoride 90 ~ 99.9 mass parts, be selected from least a kind of monomer 0.1 ~ 10 mass parts in the group that monomer containing carboxyl and the monomer containing acid anhydride form (but, wherein by vinylidene fluoride and be selected from be set to 100 mass parts by the total of the monomer containing carboxyl and at least a kind of monomer in containing group that the monomer of acid anhydride forms) carry out copolymerization after the vinylidene fluoride copolymer that obtains, be more preferably vinylidene fluoride 95 ~ 99.9 mass parts, be selected from by the monomer containing carboxyl and the group that forms containing the monomer of acid anhydride at least a kind of monomer 0.1 ~ 5 mass parts (but, wherein by vinylidene fluoride and be selected from be set to 100 mass parts by the total of the monomer containing carboxyl and at least a kind of monomer in containing group that the monomer of acid anhydride forms) carry out copolymerization after the vinylidene fluoride copolymer that obtains.
As the described monomer containing carboxyl, be preferably the monoesters etc. of unsaturated monoacid, unsaturated dibasic acid and unsaturated dibasic acid, be more preferably the monoesters of unsaturated dibasic acid, unsaturated dibasic acid.
As described unsaturated monoacid, acrylic acid etc. can be enumerated.As described unsaturated dibasic acid, maleic acid, citraconic acid etc. can be enumerated.In addition, as the monoesters of described unsaturated dibasic acid, being preferably carbon number is the material of 5 ~ 8, include, for example monomethyl maleate, ethyl maleate, citraconic acid mono-methyl and citraconic acid mono ethyl ester etc.
Wherein, as the monomer containing carboxyl, be preferably maleic acid, citraconic acid, monomethyl maleate and citraconic acid mono-methyl.
As the described monomer containing acid anhydride, the acid anhydrides of unsaturated dibasic acid can be enumerated, as the anhydride group of unsaturated dibasic acid, can maleic anhydride, anhydrous citraconic acid etc. be enumerated.
Vinylidene fluoride polymer containing functional group of the present invention is generally the polymer of the functional group with the monomer be derived from containing functional group.Such as, when using monomer containing carboxyl as monomer containing functional group, usually used as the vinylidene fluoride polymer containing functional group, the vinylidene fluoride polymer containing carboxyl can be obtained.In addition, when using monomer containing acid anhydride as monomer containing functional group, as the vinylidene fluoride polymer containing functional group, the carboxyl after by acid anhydride's hydrolysis can be had, also can have acid anhydride.
Other monomers used in the present invention refer to vinylidene fluoride and containing the monomer beyond the monomer of functional group, as other monomers, include, for example and can carry out fluorine class monomer and the hydrocarbon monomer of copolymerization with vinylidene fluoride.As carrying out the fluorine class monomer of copolymerization with vinylidene fluoride, can enumerate with perfluoro methyl vinyl ether is the perfluoroalkyl vinyl ether of representative, ethylene fluoride, trifluoro-ethylene, tetrafluoroethene and hexafluoropropylene etc.In addition, as hydrocarbon monomer, ethene, propylene and butylene etc. can be enumerated.
In addition, other monomers above-mentioned can be used alone a kind, also can use two or more.
In addition, as method (1), the methods such as suspension polymerisation, emulsion polymerisation and polymerisation in solution can be adopted, but consider from viewpoints such as the difficulties of reprocessing, be preferably the suspension polymerisation of water class, emulsion polymerisation, be particularly preferably the suspension polymerisation of water class.
In the suspension polymerisation taking water as decentralized medium, all monomers of using relative to copolymerization (other monomers of vinylidene fluoride, monomer containing functional group and copolymerization as required) 100 mass parts, in 0.005 ~ 1.0 mass parts, preferably add in the scope of 0.01 ~ 0.4 mass parts, use the suspending agents such as methylcellulose, methoxylation methylcellulose, propoxylated methyl cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, polyvinyl alcohol, polyethylene glycol oxide and gelatin.
As polymerization initiator, the positive seven fluorine propyl ester of di-isopropyl peroxydicarbonate, peroxy dicarbonate di-n-propyl ester, peroxy dicarbonate two, di-isopropyl peroxydicarbonate, isobutyryl peroxide base, two (chlorine fluorine acyl group) peroxide and two (perfluoro acidyl) peroxide etc. can be used.When all monomers used in copolymerization (other monomers of vinylidene fluoride, monomer containing functional group and copolymerization as required) are set to 100 mass parts, its use amount is 0.1 ~ 5 mass parts, is preferably 0.3 ~ 2 mass parts.
In addition, also can add chain-transferring agent to regulate the degree of polymerization of the obtained vinylidene fluoride polymer containing functional group, described chain-transferring agent comprises ethyl acetate, methyl acetate, diethyl carbonate, acetone, ethanol, normal propyl alcohol, acetaldehyde, propionic aldehyde and ethyl propionate etc.When all monomers used in copolymerization (other monomers of vinylidene fluoride, monomer containing functional group and copolymerization as required) are set to 100 mass parts, its use amount is generally 0.1 ~ 5 mass parts, is preferably 0.5 ~ 3 mass parts.
In addition, the input amount of whole monomers of using about copolymerization (other monomers of vinylidene fluoride, monomer containing functional group and copolymerization as required), add up to according to monomer: the mass ratio of water calculates, be generally 1: 1 ~ 1: 10, be preferably 1: 2 ~ 1: 5, polymerization temperature is 10 ~ 80 DEG C, and polymerization time is 10 ~ 100 hours, pressure during polymerization carries out usually adding pressure, is preferably 2.0 ~ 8.0MPa-G.
By carrying out the suspension polymerisation of water-based under these conditions, just can carry out copolymerization to other monomers of vinylidene fluoride, monomer containing functional group and copolymerization as required like a cork, and the vinylidene fluoride polymer containing functional group used in the present invention can be obtained.
In addition, when manufacturing the vinylidene fluoride polymer containing functional group by described method (2), such as following methods can be adopted.
When manufacturing the vinylidene fluoride polymer containing functional group by method (2), first vinylidene fluoride is carried out being polymerized or by vinylidene fluoride and other monomers are carried out copolymerization, obtaining vinylidene fluoride polymer.This polymerization or copolymerization are undertaken by suspension polymerisation or emulsion polymerisation usually.In addition, different from described vinylidene fluoride polymer, by being carried out by the monomer containing functional group being polymerized or the monomer containing functional group and other monomers being carried out copolymerization, obtain the polymer containing functional group.Should usually be obtained by emulsion polymerisation or suspension polymerisation by the polymer containing functional group.By further using above-mentioned vinylidene fluoride polymer and the polymer containing functional group, by the polymer graft containing functional group to vinylidene fluoride polymer, the vinylidene fluoride polymer containing functional group can be obtained.This grafting can use peroxide, also can use radiation, but preferably by under the existence of peroxide, the mixture of vinylidene fluoride polymer and the polymer containing functional group is carried out heat treated to carry out.
The logarithmic viscosity number of the vinylidene fluoride polymer containing functional group used in the present invention (by 4g resin dissolves in the DMF gained solution of 1 liter at 30 DEG C time logarithmic viscosity number.Identical below) be preferably numerical value within the scope of 0.5 ~ 10.0dl/g, be more preferably the numerical value within the scope of 1.0 ~ 8.0dl/g.If viscosity is in above-mentioned scope, be then applicable to anode for nonaqueous electrolyte secondary battery mixture.
In addition, the weight average molecular weight utilizing GPC (gel permeation chromatography) to measure to try to achieve of the vinylidene fluoride polymer containing functional group, usually in the scope of 50,000 ~ 2,000,000, is preferably in the scope of 200,000 ~ 1,500,000.
In addition, when the described vinylidene fluoride polymer containing functional group is the described vinylidene fluoride polymer containing carboxyl, the dulling luminosity ratio (A represented with following formula (1) when measuring the infrared absorption spectrum of the described vinylidene fluoride polymer containing carboxyl r) preferably in the scope of 0.1 ~ 2.0, more preferably in the scope of 0.3 ~ 1.7.A rwhen being less than 0.1, the adhesiveness of itself and collector body is likely insufficient.On the other hand, if A rmore than 2.0, then the electrolyte-resistant of obtained polymer has reduction trend.In addition, the mensuration of the infrared absorption spectrum of this polymer, being implement hot pressing to this polymer and manufacture film, being undertaken by measuring the infrared absorption spectrum of this film.
A R＝A 1650-1800/A 3000-3100(1)
In above-mentioned formula (1), A 1650-1800for at 1650 ~ 1800cm -1scope in the absorbance being derived from the absorption band of carbonyl that detects, A 3000-3100for at 3000 ~ 3100cm -1scope in the absorbance being derived from the absorption band of CH structure that detects.A rthe yardstick of the amount representing carbonyl in the vinylidene fluoride polymer containing carboxyl, the final yardstick for representing carboxyl amount.
In addition, as the vinylidene fluoride polymer containing functional group, also commercially available product can be used.
In the present invention, saponification degree is used to be the polyvinyl alcohol of 35 ~ 90mol%.
The polyvinyl alcohol that uses in the present invention need relative to the good solvent of the vinylidene fluoride polymer containing functional group and METHYLPYRROLIDONE (following omission is designated as NMP) solvable, and lower to the dissolubility of the electrolyte solvent of formation rechargeable nonaqueous electrolytic battery.Saponification degree can be used as expression polyvinyl alcohol relative to the deliquescent index of solvent, if saponification degree is too low, then higher relative to the solubility of electrolyte solvent, therefore not preferred, if saponification degree is too high, the solubility then containing the good solvent of the vinylidene fluoride polymer of functional group relative to NMP etc. reduces, therefore not preferred.The saponification degree of polyvinyl alcohol is 35 ~ 90mol%, is more preferably 50 ~ 90mol%, is particularly preferably 70 ~ 90mol%.
In addition, from the viewpoint of the capability retention of rechargeable nonaqueous electrolytic battery when sudden discharge, the saponification degree of polyvinyl alcohol is preferably 80 ~ 90mol%, is more preferably 85 ~ 90mol%.
The average degree of polymerization of described polyvinyl alcohol is preferably 100 ~ 4000, and more preferably 150 ~ 3800, be particularly preferably 200 ~ 3600.
In addition, the saponification degree of polyvinyl alcohol and average degree of polymerization can according to JIS K 6726: the test method of polyvinyl alcohol measures.
Described polyvinyl alcohol is the one of thermoplastic resin, usually by polyvinyl acetate saponification being obtained.Therefore, described polyvinyl alcohol is except with-(CH 2-CHOH)-represent construction unit beyond, also there is the construction unit being derived from vinylacetate.Described polyvinyl alcohol can have the use-(CH of about 0 ~ 8 % by mole 2-CHOH)-the construction unit that represents and be derived from vinylacetate construction unit beyond construction unit (other construction units), but preferably not there are other construction units.
In addition, even if containing other construction units, from the deliquescent viewpoint guaranteed organic solvent, preferably not there is the construction unit being derived from ethene.
In addition, as other construction units that can contain, include, for example out propionate, vinyl butyrate, vinyl monochloroacetate etc.
One large feature of rechargeable nonaqueous electrolytic battery adhesive of the present invention is, at least contain the vinylidene fluoride polymer of functional group and described polyvinyl alcohol containing described, adhesiveness is excellent, can reduce the initial irreversible capacity of rechargeable nonaqueous electrolytic battery of the present invention, and during sudden discharge, capability retention is also excellent.Its reason is not yet clear and definite, but the present inventor infers this is because described polyvinyl alcohol efficiently covers negative electrode active material.More specifically, the present inventor infers that therefore adhesiveness is excellent because described polyvinyl alcohol efficiently covers negative electrode active material, reduces owing to covering the electrolyte decomposition reaction causing negative electrode active material surface, therefore can reduce initial irreversible capacity, and then during sudden discharge, capability retention is excellent.
Rechargeable nonaqueous electrolytic battery adhesive of the present invention can containing the resin (other resins) beyond described vinylidene fluoride polymer containing functional group and described polyvinyl alcohol.The ratio of whole adhesive resin is accounted for containing the vinylidene fluoride polymer of functional group and the total ratio of described polyvinyl alcohol more large more preferred described in rechargeable nonaqueous electrolytic battery adhesive of the present invention, in whole adhesive resin 100 quality %, describedly be preferably more than 60 quality % containing the vinylidene fluoride polymer of functional group and the total of described polyvinyl alcohol, be more preferably more than 80 quality %, be particularly preferably more than 90 quality %.
In addition, for playing the function of rechargeable nonaqueous electrolytic battery adhesive of the present invention, the described polyvinyl alcohol adding proper proportion to the described vinylidene fluoride polymer containing functional group is most important.Rechargeable nonaqueous electrolytic battery adhesive of the present invention, described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.If the containing ratio of described polyvinyl alcohol is too small, then the effect of the electrolyte decomposition reaction of inhibit activities material surface reduces, therefore not preferred.The content of described polyvinyl alcohol is more than 5 quality %, is preferably more than 6 quality %.On the other hand, if the containing ratio of described polyvinyl alcohol is excessive, then the overlay film of active material surface formation is blocked up, and the resistance of active material and electrolyte interface increases, and input-output characteristic reduces, therefore not preferred.The content of described polyvinyl alcohol is below 93 quality %, is preferably below 85 quality %, is more preferably below 80 quality %, more preferably below 50 quality %, most preferably is below 30 quality %.The input-output characteristic of rechargeable nonaqueous electrolytic battery and the adhesiveness excellence of adhesive in described scope, therefore preferably.
Rechargeable nonaqueous electrolytic battery binder solution of the present invention is by described rechargeable nonaqueous electrolytic battery adhesive and solvent composition.
Solvent usually with an organic solvent.Described solvent usually uses to have and dissolves the described solvent containing the vinylidene fluoride polymer of functional group, the effect of polyvinyl alcohol, preferably uses the solvent with polarity.As the concrete example of described solvent, METHYLPYRROLIDONE, N can be listed, dinethylformamide, N, N-dimethylacetylamide, dimethyl sulfoxide (DMSO), hexamethyl phosphoramide, dioxane, oxolane, tetramethylurea, triethyl phosphate, trimethyl phosphate etc., be preferably METHYLPYRROLIDONE, N, dinethylformamide, DMA, dimethyl sulfoxide (DMSO).In addition, organic solvent can be used alone a kind, also can be mixed with two or more.
As the manufacture method of rechargeable nonaqueous electrolytic battery binder solution of the present invention, as long as by the dissolving at least partially of described vinylidene fluoride polymer containing functional group and polyvinyl alcohol in a solvent, be not particularly limited.As the manufacture method of described rechargeable nonaqueous electrolytic battery binder solution, include, for example out following method: by described vinylidene fluoride polymer containing functional group and polyvinyl alcohol simultaneously and solvent, manufacture the method for rechargeable nonaqueous electrolytic battery binder solution thus; By the described vinylidene fluoride polymer and the solvent that contain functional group, then gained mixed liquor is mixed with described polyvinyl alcohol, manufacture the method for rechargeable nonaqueous electrolytic battery binder solution thus; By described polyvinyl alcohol and solvent, then gained mixed liquor is mixed with the described vinylidene fluoride polymer containing functional group, manufacture the method for rechargeable nonaqueous electrolytic battery binder solution thus; And preparation is described containing the vinylidene fluoride polymer of functional group and the mixed liquor of the mixed liquor of solvent, described polyvinyl alcohol and solvent respectively, then by these two kinds of mixed liquor mixing, manufacture the method etc. of rechargeable nonaqueous electrolytic battery binder solution thus.
In addition, if in advance by polyvinyl alcohol and solvent, re-used after then filtering gained mixed liquor, then by the coating of anode for nonaqueous electrolyte secondary battery mixture on the current collector, dry, the mixture layer of formation then evenly, therefore preferably.
Described rechargeable nonaqueous electrolytic battery binder solution contains the vinylidene fluoride polymer of functional group and total 100 mass parts of described polyvinyl alcohol relative to described, usually the solvent containing 100 ~ 9000 mass parts, preferably containing 150 ~ 4900 mass parts, more preferably containing 250 ~ 3500 mass parts.The stability of described scope inner binder solution is excellent with workability when making electrode, therefore preferably.
Anode for nonaqueous electrolyte secondary battery mixture of the present invention is at least containing described vinylidene fluoride polymer, described polyvinyl alcohol (rechargeable nonaqueous electrolytic battery adhesive), solvent and negative electrode active material containing functional group.In addition, described anode for nonaqueous electrolyte secondary battery mixture also can contain conductive auxiliary agent as required.In addition, as solvent, the solvent forming aforementioned rechargeable nonaqueous electrolytic battery binder solution can be used as and the solvent recorded.
Described anode for nonaqueous electrolyte secondary battery mixture contains in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol described, the described polyvinyl alcohol containing 5 ~ 93 quality %.The content of described polyvinyl alcohol is preferably more than 6 quality %.In addition, the content of described polyvinyl alcohol is preferably below 85 quality %, is more preferably below 80 quality %, more preferably below 50 quality %, most preferably is below 30 quality %.
As long as the material that described negative electrode active material can insert release lithium is then not particularly limited, the negative electrode active material be made up of carbon class material, metal or alloy material, metal oxide etc. can be used.Negative electrode active material preferably uses the negative electrode active material be made up of carbonaceous material, i.e. carbon class negative electrode active material.
About the ratio of the active material related in described anode for nonaqueous electrolyte secondary battery mixture, in total 100 mass parts of described vinylidene fluoride polymer, polyvinyl alcohol and negative electrode active material containing functional group, negative electrode active material is preferably 70 ~ 99.9 mass parts, be more preferably 75 ~ 99.5 mass parts, be particularly preferably 80 ~ 99 mass parts.In addition, can containing dispersants such as conductive auxiliary agent and polyvinylpyrrolidone etc. such as carbon blacks as additive.
About the ratio of the solvent related in described anode for nonaqueous electrolyte secondary battery mixture, relative to total 100 mass parts of described vinylidene fluoride polymer, described polyvinyl alcohol and negative electrode active material containing functional group, usually the solvent containing 3 ~ 300 mass parts, preferably containing 4 ~ 200 mass parts.In described scope the stability of mixture and screening characteristics excellent, therefore preferably.The viscosity of anode for nonaqueous electrolyte secondary battery mixture of the present invention is preferably 2000 ~ 50000mPas, more preferably 5000 ~ 30000mPas.
As long as the manufacture method of anode for nonaqueous electrolyte secondary battery mixture of the present invention, by described vinylidene fluoride polymer, polyvinyl alcohol, negative electrode active material and solvent uniformly slurry containing functional group, is not particularly limited.As the manufacture method of anode for nonaqueous electrolyte secondary battery mixture, include, for example out following method: add negative electrode active material to described rechargeable nonaqueous electrolytic battery binder solution and mix, manufacture the method for anode for nonaqueous electrolyte secondary battery mixture thus; By contained by anode for nonaqueous electrolyte secondary battery mixture all composition mix simultaneously, manufacture the method for anode for nonaqueous electrolyte secondary battery mixture thus; Add described negative electrode active material to described rechargeable nonaqueous electrolytic battery adhesive and solvent mixes, manufacture the method for anode for nonaqueous electrolyte secondary battery mixture thus; And, the described solution containing the vinylidene fluoride polymer of functional group and the solution of described solvent and described polyvinyl alcohol and solvent of preparation, by these 2 kinds of solution, negative electrode active material and solvent, manufacture the method etc. of anode for nonaqueous electrolyte secondary battery mixture thus.
In addition, if in advance by polyvinyl alcohol and solvent, re-used after then filtering gained solution, then by the coating of anode for nonaqueous electrolyte secondary battery mixture on the current collector, the mixture layer formed after dry evenly, therefore preferably.
As described carbon class negative electrode active material, graphite material can be listed and there is the carbonaceous material (being also designated as Turbostratic carbon below) of the Turbostratic such as difficult graphitized carbon or easy graphitized carbon.If use the negative electrode active material be made up of this carbon class material, then can manufacture the secondary cell with high-durability and high-energy-density, therefore preferably.
As graphite material, there is the native graphite that commute graphitized carbon carries out the Delanium that high temperature (such as more than 2000 DEG C) heat treatment obtains, natural formation.The feature of graphite material is different from the carbonaceous material with Turbostratic, and carbon hexagonal gridding plane has three-dimensional regularity, and has layer structure.This structure, by the diffracted ray utilizing powder X-ray diffractometry to measure, is carried out observing after being separated respectively by 100 diffracted rays just can learn with 101 diffracted rays and 110 diffracted rays with 112 diffracted ray.In addition, learnt that the average aspect interval of the hexagonal gridding plane of carbonaceous material is reduced along with close to graphite-structure, and close to the average aspect interval 0.3354nm of ideal graphite structure, this value can utilize powder X-ray diffractometry to measure.Graphite material just can hold more lithiums because crystal structure reaches all the more, and the preferred value therefore as the average aspect interval of its index is below 0.345nm, more preferably below 0.340nm.The real density of graphite material is large compared with the real density of difficult graphitized carbon, can store macro-energy in small size, therefore improves volume energy density and preferably uses graphite material as negative electrode active material.
In addition, the real density with the graphite material of ideal structure is 2.26g/cm 3, exist real density along with crystal structure turmoil the trend of step-down.The real density of graphite material is preferably 1.9g/cm 3above, 2.0g/cm is more preferably 3above, more preferably 2.1g/cm 3above.
The carbonaceous material with Turbostratic is roughly divided into easy graphitized carbon and difficult graphitized carbon, it is characterized in that, in the mensuration of powder x-ray diffraction, do not observe the diffracted ray that can embody three-dimensional regularity, and observe the diffracted ray of the two dimension such as 10 diffracted rays or 11 diffracted rays reflection.
Easy graphitized carbon is changing into the character of graphite material after having high temperature (such as more than 2000 DEG C) heat treatment.The feature of the negative electrode active material of easy graphitized carbon is, demonstrate the charging and discharging curve that voltage is smooth change relative to the charge volume similar to difficult graphitized carbon, in the battery of negative electrode active material using easy graphitized carbon, easily detect charged state according to terminal voltage.And comparatively large with the potential difference of charge cutoff current potential, therefore there is features such as being beneficial to charging rapidly.With dilation during easy graphitized carbon discharge and recharge, therefore compared with difficult graphitized carbon, the charging capacity of unit mass and poor durability, but easily the real density of graphitized carbon is large, therefore easily obtains the capacity of unit volume.In addition, compared with difficult graphitized carbon, specific area is little, and water absorption is low, and the irreversible capacity that when therefore also having a preservation, oxidative degradation causes increases less preferred property.Easy graphitized carbon has this point of Turbostratic can utilize powder X-ray diffractometry investigation, but easily the electrochemically character of graphitized carbon is different because of the condition of raw material carburizing reagent.The structure of easy graphitized carbon changes because of these manufacturing conditions, and can learn its feature according to real density, if real density is low, then degree of carbonisation is insufficient, and irreversible capacity increases, therefore not preferred.In addition, if real density is too high, then discharge capacity reduces, therefore not preferred.Preferably easily the real density of graphitized carbon is 1.8g/cm 3above, 2.1g/cm 3below.
As described easy graphitized carbon, the average layer interval (d in (002) face preferably utilizing X-ray diffraction method to obtain 002) be the easy graphitized carbon of 0.335 ~ 0.360nm.In addition, as described easy graphitized carbon, the crystallite size (Lc in c-axis direction is preferably (002)) be the easy graphitized carbon of more than 10nm.In addition, if negative electrode active material uses d 002be in the easy graphitized carbon of described scope, then can reduce the irreversible capacity of rechargeable nonaqueous electrolytic battery, therefore preferably.
On the other hand, the feature of difficult graphitized carbon is, to compare real density little with graphite material and easy graphitized carbon, but but can hold a large amount of lithium in trickle sheaf space, even if repeated charge changes in crystal structure is also less, therefore has high-durability.In addition, even if adopt the electrolyte that propene carbonate etc. can use at low temperature, the decomposition of electrolyte is also less, and therefore low-temperature characteristics is excellent.And, identical with easy graphitized carbon, owing to having the stable charging and discharging curve of terminal voltage according to charge rate, therefore in the battery using difficult graphitized carbon, easily charged state is detected according to terminal voltage, and then comparatively large with the potential difference of charge cutoff current potential, therefore there is features such as being beneficial to charging rapidly.
The real density of described difficult graphitized carbon is preferably 1.4g/cm 3above and lower than 1.8g/cm 3.In addition, the average layer interval (d in described difficult graphitized carbon (002) face of preferably utilizing X-ray diffraction method to obtain 002) be 0.365 ~ 0.400nm.
The real density of described difficult graphitized carbon is more preferably 1.4 ~ 1.7g/cm 3, be particularly preferably 1.4 ~ 1.6g/cm 3.
If real density exceeds described scope, then charging capacity, discharge capacity may reduce, therefore not preferred.
Centre plane interval (the d of described difficult graphitized carbon 002) be more preferably 0.370 ~ 0.395nm, be particularly preferably 0.375 ~ 0.390nm.
The Lc of described difficult graphitized carbon (002)be preferably below 10nm, be more preferably below 5nm, more preferably below 3nm.In addition, if Lc (002)lower than 1.0nm, then carbon skeleton is formed insufficient, therefore not preferred.Thus, preferred Lc (002)for more than 1.0nm below 10nm, more preferably more than 1.0nm below 5nm, is particularly preferably more than 1.0nm below 3nm.
In the example of described carbon class negative electrode active material, Delanium, native graphite are classified into graphite material, and easy graphitized carbon and difficult graphitized carbon are classified into Turbostratic carbon.In addition, described negative electrode active material, owing to having various different feature, therefore can be used alone a kind according to object, also can use two or more.As described negative electrode active material, for realizing excellent input-output characteristic and the durability of rechargeable nonaqueous electrolytic battery, more preferably difficult graphitized carbon.In addition, when using difficult graphitized carbon, there is the technical matters point that the initial irreversible capacity of rechargeable nonaqueous electrolytic battery is relatively large, but the present invention is by using described vinylidene fluoride polymer containing functional group and polyvinyl alcohol as adhesive, can reduce initial irreversible capacity.
If the average grain diameter of described negative electrode active material is too small, then specific area becomes large, and irreversible capacity increases, if particle diameter is little, then mean free path shortens, fail safe step-down during short circuit, therefore not preferred.On the other hand, if average grain diameter is excessive, then electrode active material layer is uneven, and in particle, the diffusion free travel of lithium increases, and is thus difficult to discharge and recharge rapidly, therefore not preferred.In addition, for improving input-output characteristic, being necessary to expand electrode area, in order to expand electrode area in limited volume, being necessary to make electrode active material layer thinning, therefore needing particle diameter less.From this point of view, the average grain diameter of negative electrode active material is preferably 1 ~ 40 μm, is more preferably 2 ~ 30 μm, is particularly preferably 3 ~ 15 μm.
If the specific area of described negative electrode active material is too small, then binding agent is difficult to incorporate in active material, can guarantee sufficient adhesiveness, therefore not preferred.And the response area for discharge and recharge tails off, be difficult to discharge and recharge rapidly, therefore not preferred.On the other hand, if specific area is excessive, then electrolytical decomposition amount increases, and the irreversible capacity at initial stage increases, therefore not preferred.
The specific area of described negative electrode active material is preferably 0.3 ~ 25m 2/ g, more preferably 0.5 ~ 20m 2/ g, is particularly preferably 2 ~ 10m 2/ g.
As the negative electrode active material be made up of metal oxide, such as, lithium titanate, lithium vanadate etc. can be used.
The manufacture method of described carbon class negative electrode active material there is no particular determination, such as, by by delimings such as coconut husk charcoals, then calcines gained deliming charcoal, thus manufactures.
In addition, described negative electrode active material can use commercially available prod, and the commercially available prod of carbon class negative electrode active material can use Carbotron P S (F) (Co., Ltd. KUREHA system, difficult graphitized carbon), BTR (registered trade mark) 918 (BTR NEW ENERGY MATERIALS INC Inc., native graphite), MCMB6-28 (Osaka Gas Chemical Co., Ltd. system, Delanium) etc.In addition, as the negative electrode active material be made up of metal oxide, ENERMIGHT (registered trade mark) LT series LT106 (Ishihara Sangyo Kaisha, Ltd.'s system, lithium titanate) etc. can be used.
Anode for nonaqueous electrolyte secondary battery of the present invention, by by described anode for nonaqueous electrolyte secondary battery mixture coating on the current collector, obtains after drying.
In addition, in the present invention by the coating of anode for nonaqueous electrolyte secondary battery mixture on the current collector, the layer formed by anode for nonaqueous electrolyte secondary battery mixture formed after dry is designated as mixture layer.
The collector body of anode for nonaqueous electrolyte secondary battery of the present invention and the peel strength excellence of mixture layer.In described anode for nonaqueous electrolyte secondary battery, to use anode for nonaqueous electrolyte secondary battery mixture of the present invention for feature, the peel strength of collector body and mixture layer is excellent.
Although the reason of the peel strength excellence of the collector body of anode for nonaqueous electrolyte secondary battery of the present invention and mixture layer is not yet clear and definite, infer it is because mixture contains described polyvinyl alcohol, therefore the peel strength of collector body and mixture layer is excellent.
As the collector body that the present invention uses, include, for example copper, nickel etc., as its shape, include, for example out metal forming or wire netting etc.As collector body, be preferably Copper Foil.
The thickness of collector body is preferably 5 ~ 100 μm, more preferably 5 ~ 20 μm.
In addition, the thickness of mixture layer (one side) is preferably 10 ~ 250 μm, is more preferably 20 ~ 150 μm.
When manufacturing anode for nonaqueous electrolyte secondary battery of the present invention, described anode for nonaqueous electrolyte secondary battery mixture is coated at least one side of described collector body, is preferably coated on two sides.Method during coating is not particularly limited, and can list and carry out the method such as being coated with metering bar coater, die applicator, comma coater.In addition, as the drying carried out after coating, usually 1 ~ 300 minute is carried out with the temperature of 50 ~ 150 DEG C.In addition, pressure time dry is not particularly limited, but usually under atmospheric pressure or under decompression carries out.And, after carrying out drying, can heat-treat.When heat-treating, at the temperature of 100 ~ 160 DEG C, carry out 1 ~ 300 minute.In addition, heat treatment temperature and described drying repeat, and these operations can be independent process, also can for the operation of carrying out continuously.
In addition, also punching press process can be carried out further.When carrying out punching press process, stamping pressure is not particularly limited, but is preferably 1.0MPa (0.2t/cm 2) ~ 52.0MPa (10t/cm 2), be more preferably 1.6MPa (0.3t/cm 2) ~ 41.6MPa (8t/cm 2).Carry out punching press process and then can improve electrode density, therefore preferably.
Anode for nonaqueous electrolyte secondary battery of the present invention can be manufactured in order to top method.In addition, as the Rotating fields of anode for nonaqueous electrolyte secondary battery, when anode for nonaqueous electrolyte secondary battery mixture is coated on the one side of collector body, for the double-decker of mixture layer/collector body, when anode for nonaqueous electrolyte secondary battery mixture is coated on the two sides of collector body, it is the three-decker of mixture layer/collector body/mixture layer.
Anode for nonaqueous electrolyte secondary battery of the present invention is by using described anode for nonaqueous electrolyte secondary battery mixture, the peel strength of its collector body and mixture layer is excellent, therefore in punching press, crack, electrode not easily produces crack or stripping in the operation such as winding, contribute to improving productivity, therefore preferably.
The peel strength of anode for nonaqueous electrolyte secondary battery of the present invention as aforementioned shown collector body and mixture layer is excellent, specifically, when utilizing 180 ° of disbonded tests to measure according to JIS K6854, the peel strength of collector body and mixture layer is generally 0.5 ~ 20gf/mm, is preferably 1 ~ 15gf/mm.
The collector body of anode for nonaqueous electrolyte secondary battery of the present invention and the peel strength excellence of mixture layer.
The feature of rechargeable nonaqueous electrolytic battery of the present invention is, has described anode for nonaqueous electrolyte secondary battery.
As rechargeable nonaqueous electrolytic battery of the present invention, except there is described anode for nonaqueous electrolyte secondary battery, be not particularly limited.As rechargeable nonaqueous electrolytic battery, have described electrode for nonaqueous electrolyte secondary battery as negative pole, the position beyond negative pole such as positive pole, barrier film etc. can use well-known product.
As described positive pole, as long as have the positive active material of mainly serving as positive pole reaction, and there is current-collecting function, then be not particularly limited, in most cases by the positive electrode material mixture layer containing positive active material and play function as collector body and play and keep the positive electrode collector of positive electrode material mixture layer effect to form.
When rechargeable nonaqueous electrolytic battery is lithium rechargeable battery, the positive active material forming positive electrode material mixture layer is preferably the lithium class positive active material at least containing lithium.
As lithium class positive active material, include, for example out and use LiCoO 2, LiNi xco 1-xo 2general formula LiMY such as (0≤x≤1) 2(M is at least one of the transition metal such as Co, Ni, Fe, Mn, Cr, V; Y is the chalcogens such as O, S) the composition metal chalcogen compound, the LiMn that represent 2o 4deng the composite metal oxide and the LiFePO that adopt spinel structure 4deng olivine-type lithium compound etc.In addition, as described positive active material, commercially available prod can be used.
The specific area of described positive active material is preferably 0.05 ~ 50m 2/ g.
Be not particularly limited as the adhesive resin used when forming positive electrode material mixture layer, widely used adhesive resin in well-known lithium rechargeable battery can be preferably used in, such as, can use fluorine resin, acrylonitrile-butadiene copolymer and hydride and the ethylene-methyl acrylate copolymers etc. such as polytetrafluoroethylene, polyvinylidene fluoride, fluorubber.In addition, as described fluorine resin, also vinylidene fluoride analog copolymer can be used.As vinylidene fluoride analog copolymer, vinylidene fluoride-monomethyl maleate copolymer etc. can be used.
When rechargeable nonaqueous electrolytic battery is lithium rechargeable battery, be preferably by aluminium or its alloy composition as positive electrode collector, be wherein preferably aluminium foil.The thickness of collector body is generally 5 ~ 100 μm.
As described barrier film, it is the barrier film forming rechargeable nonaqueous electrolytic battery, by positive pole and negative pole electric insulation, plays and keeps electrolyte effect.Be not particularly limited as barrier film, include, for example out the perforated membrane of individual layer and multilayer, nonwoven fabrics etc., the perforated membrane, nonwoven fabrics etc. of this individual layer and multilayer are made up of polyimides family macromolecule, polyether sulfone, polysulfones, polyether-ketone, polystyrene, polyethylene glycol oxide, Merlon, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, the potteries etc. such as the polyesters macromolecules such as the TPO such as polyethylene, polypropylene macromolecule, PETG, aromatic polyamide family macromolecule, Polyetherimide and these mixture.Particularly preferably use the perforated membrane of TPO macromolecule (polyethylene, polypropylene).As the high-molecular porous film of TPO, include, for example out by Polypore Co., Ltd. with commercially available single-layer polypropylene barrier film, monolayer polyethylene barrier film and the polypropylene, polyethylene/polypropylene 3 layers of barrier film etc. of Celgard (registered trade mark).
Rechargeable nonaqueous electrolytic battery of the present invention, compared with conventional non-aqueous solution electrolitc secondary cell, can reduce initial irreversible capacity, and during sudden discharge, capability retention is excellent, can improve charge/discharge cycle characteristics.
In addition, in this specification, the analytical method of adhesive is recorded as follows.
(the logarithmic viscosity number assay method of the vinylidene fluoride polymer containing functional group)
Described logarithmic viscosity number is by 4g resin dissolves gained solution log viscosities at 30 DEG C after 1 liter of DMF.Logarithmic viscosity number η ican calculate in the following way: vinylidene fluoride polymer 80mg being contained functional group is dissolved in the DMF of 20ml, in the thermostat of 30 DEG C, use Ubbelohde viscometer, calculate according to following formula.
η i＝(1/C)·ln(η/η 0)
η is the viscosity of polymer solution herein, η 0for the viscosity that solvent DMF is independent, C is 0.4g/dl.
(the saponification degree assay method of polyvinyl alcohol)
The saponification degree of polyvinyl alcohol and average degree of polymerization can according to JIS K 6726: the test method of polyvinyl alcohol measures.
(viscosity measurement of cathode agent)
The detailed content of assay method illustrates as follows.On the detection head of E type viscosimeter (Toki Sangyo Co., Ltd. RE550R), 3 ° × R14 (angle of taper 3 °, radius 14mm) conical rotor is installed after being screwed into armature spindle before measuring.In addition the sample cup of band temp regulating function is adjusted to 25 DEG C in advance.
Be determined as follows and carry out.Sample cup is removed from detection head, uses syringe that homogeneous mixture is injected the middle body of 0.55mL sample cup.After injecting sample, again sample cup is arranged on detection head.1 minute is left standstill, after sample temperature being adjusted to 25 DEG C, with 2s after injecting sample -1shear rate carry out the mensuration of 5 minutes.Measure the viscosity after measuring beginning 5 points, as the viscosity of mixture.
Embodiment
Show embodiment for the present invention below and further describe, but the present invention is not limited to following explanation.
The physical property of the negative electrode active material used in embodiment, comparative example as shown in the following Table 1.In addition, with the active material related in following table 1 all for carbon class negative electrode active material.
Table 1
Each physical property of described table 1 measures by the method for following record.
(1) average grain diameter (Dv50 (μm))
In about 0.1g negative electrode active material, add 3 dispersants (cationic based surfactants " SN WET 366 " (SAN NOPCO Inc.)), dispersant is fused in negative electrode active material.Then, add 30ml pure water, by ultrasonic cleaning and dispersion after about 2 minutes, obtain the domain size distribution of particle diameter 0.5 ~ 3000 μm of scope with particle size distribution measuring device (Shimadzu Seisakusho Ltd. " SALD-3000J ").
According to described domain size distribution, be that the particle diameter of 50% is set to average grain diameter (Dv50 (μm)) by cumulative volume.
(2) the average aspect interval (d of carbon class negative electrode active material 002) and the crystallite size (Lc in c-axis direction (002))
Carbon class negative electrode active material powder is filled into test portion frame, uses PANalytical Inc. X ' PertPRO, utilize symmetric reflective method to measure.Under electric current/applying voltage is the condition of 40mA/45kV in applying, using utilizing Ni filter through the CuK α line (wavelength X=0.15418nm) of monochromatization process as line source, obtain X-ray diffraction figure.When revising diffraction pattern, do not carry out the relevant corrections such as lorentz polarization factor, absorption factor and atomic scattering factor, and utilize Rachinger method only to carry out K α 1, K α 2doublet correction.(002) angle of diffraction uses (111) diffracted ray of standard substance high-purity silicon powder to revise, and the wavelength of CuK α line is set to 0.15418nm, calculates d by following Bragg formula 002.In addition, the half breadth of the half breadth obtained according to utilization (002) diffracted ray integration method and (111) diffracted ray of standard substance high-purity silicon powder, uses Alexander curve to obtain β 1/2, the crystallite thickness Lc in c-axis direction is calculated according to following Scherrer formula (002).Herein, form factor K gets 0.9.
Numerical expression 1
d 002 = λ 2 sin θ (Bragg formula)
L C ( 002 ) = K · λ β 1 / 2 · cos θ (Scherrer formula)
(3) butanols method real density (JIS R7212) (ρ b)
The method specified with JIS R7212 is benchmark, measures real density according to carbon class negative electrode active material butanols method.Summary is as described below.
Quality (the m of the band side pipe specific gravity bottle of correct weighing internal volume 40ml 1).Then, smoothly put into test portion, bottom it, form about 10mm thickness, then correctly weigh its quality (m 2).Wherein slowly add n-butyl alcohol, form 20mm left and right thickness in bottom.Then, gently shake specific gravity bottle, after confirming no longer to occur air pocket, put into vacuum desiccator, be slowly vented, furnishing 2.0 ~ 2.7kPa.Keep more than 20 minutes at this pressure, taken out after no longer producing bubble, then fill with n-butyl alcohol, immerse constant temperature water tank (being adjusted to 30 ± 0.03 DEG C) more than 15 minutes after being stoppered lid, the liquid level of n-butyl alcohol is adjusted to graticule.Then, to be taken out and by outside wiped clean, cool to room temperature, then correctly weighs quality (m 4).
Then, only fill same specific gravity bottle with n-butyl alcohol, similarly immerse in constant temperature water tank as previously mentioned, after adjustment graticule, weigh quality (m 3).
In addition, before being about to use, make it seethe with excitement, after removing dissolved gases, distilled water is put into specific gravity bottle, similarly immerse in constant temperature water tank as previously mentioned, after adjustment graticule, weigh quality (m 5).
ρ bcalculated by following formula.ρ B＝(m 2-m 1)(m 3-m 1)d/[{m 2-m 1-(m 4-m 3)}(m 5-m 1)]
D is the proportion (0.9946 (g/cm of water 30 DEG C time herein 3)).
(4) specific area (SSA)
Use the approximate expression vm=1/ (v (1-x)) derived by BET formula, utilize the single-point method of the N2 adsorption under liquid nitrogen temperature (relative pressure x=0.3) to obtain vm, and calculate the specific area of test portion (negative electrode active material) according to following formula.
Specific area=4.35 × vm (m 2/ g)
In the approximate expression derived by described BET formula, vm is for forming the adsorbance (cm needed for monolayer on test portion surface 3/ g), v is the adsorbance (cm of actual measurement 3/ g), x is relative pressure.
Specifically, use MICROMERITICS Inc. " Flow Sorb II2300 ", under following mensuration liquid nitrogen temperature, nitrogen is to the adsorbance of carbonaceous material.
The negative electrode active material pulverized into about 5 ~ 50 μm of particle diameters is filled in test portion pipe, flows into the helium containing 30 % by mole of nitrogen concentration, test portion pipe is cooled to-196 DEG C, and makes N2 adsorption on negative electrode active material.Then, developmental tube is returned to room temperature.Now, utilize thermal conductivity detector (TCD) to measure the nitrogen quantity departed from from test portion, it can be used as adsorbed gas scale of construction v.
The following method manufacture recorded of negative electrode active material of the carbon class negative electrode active material being derived from coconut husk charcoal is recited as in described table 1.
[Production Example 1]
(being derived from the manufacture of the carbon class negative electrode active material of coconut husk charcoal)
Load 30g and be ground into the coconut husk charcoal (Philippine's product) of below 1mm average grain diameter and 35% hydrochloric acid of 100g, stir after 2 hours at 150 DEG C, filter, use the ion exchange water of 100 DEG C by filtration residue again, abundant washing, at 120 DEG C, drying 2 hours, obtains deliming charcoal.
The deliming charcoal obtained thus is pulverized and classification, after making the carbon matrix precursor particulate of average grain diameter about 10 μm, at 1250 DEG C, carries out formally calcining in 1 hour, obtain the carbon class negative electrode active material being derived from coconut husk charcoal.In addition, the difficult graphitized carbon of carbon class negative electrode active material of coconut husk charcoal is derived from.
As the negative electrode active material beyond the carbon class negative electrode active material being derived from coconut husk charcoal described in described table 1, it is use commercially available prod as follows.
In table 1, the negative electrode active material being denoted as Carbotron P is Carbotron P S (F) (Co., Ltd. KUREHA system) (difficult graphitized carbon), and the negative electrode active material being denoted as MCMB6-28 is MCMB6-28 (Osaka Gas Chemical Co., Ltd. system) (Delanium).
[Production Example 2]
(manufacture of the vinylidene fluoride polymer containing functional group)
Be drop into ion exchange water 1040g, methylcellulose 0.8g, ethyl acetate 2.5g, di-isopropyl peroxydicarbonate 4g, vinylidene fluoride 396g and monomethyl maleate 4g in the autoclave of 2 liters in inner capacities, at 29 DEG C, implement suspension polymerisation 30 hours.Maximum pressure during this reaches 4.2MPa.After after being polymerized, polymer paste being carried out dewater, washing, at 80 DEG C dry 20 hours, obtain containing the pulverous vinylidene fluoride polymer containing functional group of carboxyl as functional group.
In addition, polymerization yield is 90 quality %, and the logarithmic viscosity number of the vinylidene fluoride polymer containing functional group obtained is 1.1dl/g.
(embodiment 1)
(preparation of mixture)
The vinylidene fluoride polymer containing functional group obtained in described Production Example 2 is made to be dissolved in nmp solution 39.2 mass parts containing the vinylidene fluoride polymer content 13 quality % of functional group of METHYLPYRROLIDONE (being also denoted as NMP below) and acquisition, polyvinyl alcohol (being also denoted as PVA below) (Co., Ltd. kuraray kuraray POVALPVA-217) is made to be dissolved in NMP and nmp solution 9 mass parts of the PVA content 10 quality % obtained, active material (being derived from the carbon class negative electrode active material of coconut husk charcoal) 94 mass parts, add NMP again to stir, make the electrode composition that solid concentration is 56 quality %.The mass fraction of active material, vinylidene fluoride polymer containing functional group and PVA is 94: 5.1: 0.9.
(mensuration of peel strength)
(making of peel strength measuring electrode)
Metering bar coater is used to be uniformly coated on by described electrode composition on the one side of thickness 10 μm of Copper Foils, dry rear aggregate thickness is made to become 100 μm with pad, by it in a nitrogen environment 110 DEG C of heat dryings 30 minutes, produce electrode assembly (peel strength measuring electrode).
The mensuration of the peel strength of electrode composition layer (in the electrode assembly)
Coating electrode mixture is gone up and heat drying at collector body (Copper Foil), using electrode assembly described in gained as test portion, the peel strength utilizing 180 ° of disbonded tests to determine electrode composition layer to peel off from collector body according to JIS K6854 (mensuration of peel strength).
Specifically, use chopper that described electrode assembly is cut into wide 2cm × long 5cm, at electrode structure face (electrode composition layer surface) adhesive tape (NITTO TAPE), with 7mPas punching press 20 seconds, after making adhesive tape and electrode structure face fully bond, as test portion.
After the Copper Foil of described test portion being peeled 2.7cm with the angle of 90 °, at the upper fixing test portion of compression test (ORIENTEC Inc. STA-1150), be stretched to 180 ° with 200mm/min, the value obtained divided by structure width (20mm) by the load mean value between displacement 7mm ~ 23mm is as peel strength.
(assessment of battery performance, the mensuration of irreversible capacity)
(making of discharge and recharge test electrode)
Described electrode composition is uniformly coated on the one side of thickness 18 μm of Copper Foils, at 120 DEG C to its heating, dry 25 minutes.Stamping-out becomes that diameter 15mm's is discoid, carries out punching press, produce negative electrode (in addition, also this negative electrode being designated as discharge and recharge test electrode, carbon electrode) to it.In addition, the active material quality adjustment in electrode is become 10mg.
(discharge and recharge test method)
Described active material (being derived from the carbon class negative electrode active material of coconut husk charcoal) is used as the negative electrode active material forming non-aqueous matchmaker secondary battery negative pole, but in order to when not affecting by counter electrode performance inconsistency high accuracy assess effect of the present invention, the i.e. reduction effect of irreversible capacity, described irreversible capacity is that not implementing in cell active materials of producing by adding adhesive (vinylidene fluoride polymer containing functional group or PVA) is adulterated and residual capacity, and the stable lithium metal of operating characteristic is as counter electrode (negative pole), form the lithium rechargeable battery of electrode obtained above as positive pole, and assess its characteristic.
Namely, invention is anode for nonaqueous electrolyte secondary battery mixture or anode for nonaqueous electrolyte secondary battery etc., but when assessing capability retention when irreversible capacity and aftermentioned sudden discharge, use electrode as positive pole exceptionally, instead of negative pole.
(making of discharge and recharge testing battery)
By punching press, described discharge and recharge test electrode is pressurizeed, be crimped in 2016 sizes (diameter 20mm, thickness 1.6mm) button cell tank and cover on the stainless (steel) wire disk of the diameter 17mm of institute's spot welding, make electrode.
Lithium electrode is prepared in the glove box of Ar environment.The stainless (steel) wire disk of spot welding diameter 17mm is covered in advance outside the button cell tank of 2016 sizes, then the lithium metal thin plate stamping-out of thickness 0.5mm is become that diameter 15mm's is discoid, be crimped on stainless (steel) wire disk, made electrode (counter electrode).
Use the electrode pair that manufactures thus, by ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate according to 1: 2: 2 Capacity Ratio be mixed to form mixed solvent, in this mixed solvent, add LiPF according to the ratio of 1.5mol/L 6as electrolyte, use the barrier film of the fine pore film of the borosilicate fiberglass that the pad of polyethylene is 19mm as diameter, in Ar glove box, assemble the button type nonaqueous electrolyte class lithium secondary battery of 2016 sizes.
(measurement of battery capacity)
Use charge/discharge testing device (Japan's system system " TOSCAT "), discharge and recharge test is carried out to the lithium secondary battery of said structure.Utilize constant current and the doping reaction of constant voltage process enforcement to the lithium of discharge and recharge test electrode, recycling low current method is implemented to remove doping reaction.Herein, positive pole uses in the battery of lithium chalcogen compound, lithium is " charging " to the doping reaction of carbon electrode, as test cell of the present invention, counter electrode uses in the battery of lithium metal, be called " electric discharge " the doping reaction of carbon electrode, according to used counter electrode, the address mode of lithium to the doping reaction of identical carbon electrode is not identical.Therefore, herein for sake of convenience, the doping reaction of lithium to carbon electrode is designated as " charging ".
Otherwise " electric discharge " refers to the charging reaction in test cell, but it is also lithium from removing doping reaction negative electrode active material, therefore for sake of convenience, is designated as " electric discharge ".The charging method herein adopted is constant current and constant voltage process, specifically, before terminal voltage becomes 0mV, with 0.5mA/cm 2carry out constant current charge, after terminal voltage reaches 0mV, carry out constant-potential charge with terminal voltage 0mV, continue to current value and reach 20 μ A.Now, by the material with carbon element quality of supplied electricity divided by electrode, and income value is defined as the charging capacity (mAh/g) of the unit mass of material with carbon element.
After charging terminates, open cell circuit 30 minutes, then discharge.Electric discharge is with 0.5mA/cm 2carry out constant current electric discharge, final voltage is 1.5V.Now, by the material with carbon element quality of the electricity discharged divided by electrode, and income value is defined as the discharge capacity (mAh/g) of material with carbon element unit mass.Irreversible capacity charging capacity-discharge capacity calculates.
The measured value of the test cell (adding up to 3) using identical test portion to make is averaged, determines charge/discharge capacity and irreversible capacity.
The mensuration of capability retention (when the assessment of battery performance, sudden discharge)
(sudden discharge test)
As shown in above-mentioned (measurement of battery capacity), after discharge and recharge is carried out to the lithium secondary battery (discharge and recharge testing battery) of said structure, again carry out discharge and recharge in the same way.
Then, before terminal voltage becomes 0V, with 0.5mA/cm 2after carrying out the charging of constant current, carry out the charging of constant voltage with terminal voltage 0mV, before current value decays to 20 μ A, charge.After charging terminates, open cell circuit 30 minutes, then discharge.Before cell voltage arrives 1.5V, with fixing current density 12.5mA/cm 2(being equivalent to 5C) and 25mA/cm 2(being equivalent to 10C) discharges, and obtains respective discharge capacity.By each discharge capacity divided by 0.5mA/cm 2time discharge capacity, and capability retention (%) when income value being defined as sudden discharge.
The measured value of the test cell (adding up to 3) using identical test portion to make is averaged.
Result is as shown in table 3.
(embodiment 2 ~ 5, comparative example 1,2)
Except described containing the nmp solution of vinylidene fluoride polymer content 13 quality % of functional group and the use amount of the nmp solution of PVA content 10 quality % by changing, as shown change containing beyond the vinylidene fluoride polymer of functional group and the mass ratio of PVA recorded by table 2, carry out similarly to Example 1.
Result is as shown in table 3.
(embodiment 6 ~ 9, comparative example 3,4)
As shown in table 2, except polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-217) is altered to polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-105), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-706), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-205), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-235), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-505), or beyond polyvinyl alcohol (kuraray LM polymer LM10HD), carry out similarly to Example 1.
Result is as shown in table 3.
(embodiment 10,11, comparative example 5,6)
As shown in table 2, except passing through that described active material (being derived from the carbon class negative electrode active material of coconut husk charcoal) is changed to active material (Carbotron P), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-217) is changed to polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-205), and change described containing the nmp solution of vinylidene fluoride polymer content 13 quality % of functional group and the use amount of the nmp solution of PVA content 10 quality %, thus change containing beyond the vinylidene fluoride polymer of functional group and the mass ratio of PVA, carry out similarly to Example 1.
Result is as shown in table 3.
(embodiment 12,13, comparative example 7,8)
As shown in table 2, except passing through that described active material (being derived from the carbon class negative electrode active material of coconut husk charcoal) is changed to active material (Osaka Gas Chemical Co., Ltd. MCMB6-28), polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-217) is changed to polyvinyl alcohol (Co., Ltd. kuraray kuraray POVAL PVA-205), and change described containing the nmp solution of vinylidene fluoride polymer content 13 quality % of functional group and the use amount of the nmp solution of PVA content 10 quality %, thus change containing beyond the vinylidene fluoride polymer of functional group and the mass ratio of PVA, carry out similarly to Example 1.
Result is as shown in table 3.
In addition, during actual use rechargeable nonaqueous electrolytic battery, not only to the characteristic as battery, also the various condition such as productivity, price is studied, then determine to use which kind of rechargeable nonaqueous electrolytic battery.In addition, in the composition that anode for nonaqueous electrolyte secondary battery mixture contains, the composition of tremendous influence is caused to be negative electrode active material to rechargeable nonaqueous electrolytic battery as the characteristic (electrical characteristic) of battery.Therefore, in embodiments of the invention, comparative example, in the embodiment, comparative example of the identical active material of use, effect of the present invention is studied.
In addition, judge when reality uses, to there is sufficient performance using under type: use when being derived from the carbon class negative electrode active material of coconut husk charcoal or Carbotron P as active material, be more than 3.5gf/mm by peel strength, irreversible capacity when being below 75mAh/g, sudden discharge capability retention being more than 90% when being equivalent to 5C, being the mode of more than 60% when being equivalent to 10C; And when using MCMB6-28 as active material, be more than 3.5gf/mm by peel strength, irreversible capacity when being below 20mAh/g, sudden discharge capability retention being more than 90% when being equivalent to 5C, being the mode of more than 70% when being equivalent to 10C.
Table 3
* 1: the carbon class negative electrode active material being derived from coconut husk charcoal
*2：CarbotronP
*3：MCMB6-28
(embodiment 14)
(cyclic test)
(making of negative electrode)
The electrode composition of embodiment 1 is uniformly coated on the one side that thickness is the Copper Foil of 18 μm, 120 DEG C of heating, dry 25 minutes.After drying, stamping-out becomes that diameter 15mm's is discoid, and is carried out punching press, makes negative electrode.In addition, the Mass adjust-ment of the active material had by discoid negative electrode becomes 10mg.
(making of anode electrode)
In cobalt acid lithium (Japan Chemical Industry system " Cellseed C-5 ") 94 mass parts, carbon black 3 mass parts, polyvinylidene fluoride (Co., Ltd. KUREHA KF#1300) 3 mass parts, carbon black 3 mass parts, add NMP mix, make positive pole mixture.Gained mixture is uniformly coated on thickness 50 μm of aluminium foils.After drying, coated electrode stamping-out is become diameter 14mm's is discoid, make anode electrode.In addition, the cobalt acid lithium amount in adjustment anode electrode, makes the charging capacity of active unit quality in the embodiment 7 measured by the method described in aforementioned (measurement of battery capacity) become 95%.With cobalt acid lithium capacity for 150mAh/g calculates.
Use the electrode pair that manufactures thus, by ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate according to 1: 2: 2 Capacity Ratio be mixed to form mixed solvent, in this mixed solvent, add LiPF according to the ratio of 1.5mol/L 6as electrolyte, use the pad of polyethylene as the barrier film of the fine pore film of the borosilicate fiberglass of diameter 19mm, in Ar glove box, assemble the button type nonaqueous electrolyte class lithium secondary battery of 2032 sizes.
Herein, after first repeated charge carries out burin-in process 3 times, start cyclic test.The constant current adopted in cyclic test and constant voltage condition are, with fixing current density 2.5mA/cm before cell voltage becomes 4.2V 2charge, then make current value consecutive variations voltage be remained on 4.2V (simultaneously remaining constant voltage), before current value arrives 50 μ A, continue charging.After charging terminates, open cell circuit 10 minutes, then discharge.Before cell voltage reaches 3.0V, with fixed current density 2.5mA/cm 2discharge.Repeatedly carry out this charging and electric discharge 250 times at 50 DEG C, by after 30 times with 250 times after discharge capacity divided by discharge capacity first, obtain capacity dimension holdup (%).
Result is as shown in table 4.
(comparative example 9)
The electrode composition of described embodiment 1 is replaced to the electrode composition of comparative example 1, the charging capacity of the unit mass of the active material that the charging capacity of the unit mass of the active material related in embodiment 1 is related in comparative example 1, carry out similarly to Example 14 in addition, obtain capacity dimension holdup (%).
Result is as shown in table 4.
In the composition that anode for nonaqueous electrolyte secondary battery mixture contains, the composition of tremendous influence is caused to be negative electrode active material to the capacity dimension holdup of rechargeable nonaqueous electrolytic battery.Judge, using under type, there is when reality uses sufficient capacity dimension holdup: use the carbon class negative electrode active material being derived from coconut husk charcoal in the embodiment 14 and comparative example 9 of active material, capacity dimension holdup after 30 times is more than 91%, and the mode of capacity dimension holdup more than 50% after 250 times.
Table 4
* 1: the carbon class negative electrode active material being derived from coconut husk charcoal

Claims (10)

1. a rechargeable nonaqueous electrolytic battery adhesive, is characterized in that, at least comprises vinylidene fluoride polymer containing functional group and saponification degree is the polyvinyl alcohol of 35 ~ 90mol%,
Described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
2. rechargeable nonaqueous electrolytic battery adhesive as claimed in claim 1, wherein, the average degree of polymerization of described polyvinyl alcohol is 100 ~ 4000.
3. a rechargeable nonaqueous electrolytic battery binder solution, it is by the rechargeable nonaqueous electrolytic battery adhesive described in claim 1 or 2 and solvent composition.
4. an anode for nonaqueous electrolyte secondary battery mixture, is characterized in that, at least comprises the vinylidene fluoride polymer containing functional group, polyvinyl alcohol, negative electrode active material and solvent that saponification degree is 35 ~ 90mol%,
Described containing in the vinylidene fluoride polymer of functional group and the total 100 quality % of described polyvinyl alcohol, the described polyvinyl alcohol containing 5 ~ 93 quality %.
5. anode for nonaqueous electrolyte secondary battery mixture as claimed in claim 4, wherein, the average degree of polymerization of described polyvinyl alcohol is 100 ~ 4000.
6. the anode for nonaqueous electrolyte secondary battery mixture as described in claim 4 or 5, wherein, described negative electrode active material is made up of carbonaceous material.
7. the anode for nonaqueous electrolyte secondary battery mixture as described in claim 4 or 5, wherein, the difficult graphitized carbon of described negative electrode active material.
8. the anode for nonaqueous electrolyte secondary battery mixture as described in claim 4 or 5, wherein, described negative electrode active material is easy graphitized carbon.
9. an anode for nonaqueous electrolyte secondary battery, it by the anode for nonaqueous electrolyte secondary battery mixture coating according to any one of claim 4 ~ 8 on the current collector, obtains after dry.
10. a rechargeable nonaqueous electrolytic battery, it has anode for nonaqueous electrolyte secondary battery as claimed in claim 9.
CN201380043612.2A 2012-09-18 2013-09-17 Rechargeable nonaqueous electrolytic battery binding agent, rechargeable nonaqueous electrolytic battery binder solution, anode for nonaqueous electrolyte secondary battery mixture and application thereof Expired - Fee Related CN104584288B (en)

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