Classifications

• • 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
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
  • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
  • C08F220/281—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing only one oxygen, e.g. furfuryl (meth)acrylate or 2-methoxyethyl (meth)acrylate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/26—Esters containing oxygen in addition to the carboxy oxygen
  • C08F220/28—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety
  • C08F220/282—Esters containing oxygen in addition to the carboxy oxygen containing no aromatic rings in the alcohol moiety and containing two or more oxygen atoms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
  • H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
  • H01B1/12—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances organic substances
  • H01B1/122—Ionic conductors
• • 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
  • H01M2300/00—Electrolytes
  • H01M2300/0085—Immobilising or gelification of electrolyte
• • 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

Definitions

• the present invention relates to a gel electrolyte forming agent, a gel electrolyte forming composition containing the gel electrolyte forming agent and a liquid medium, a gel electrolyte formed from the gel electrolyte forming composition, and an electricity storage provided with the gel electrolyte Regarding devices.
• a power storage device having a high voltage and a high energy density has been required as a power source for driving electronic equipment.
• the electrolyte ion conductor
• a liquid state substance has high ionic conductivity. Therefore, in a power storage device such as a lithium ion secondary battery or a lithium ion capacitor, a liquid electrolyte in which a lithium electrolyte salt is dissolved in a solvent mainly composed of propylene carbonate, ethylene carbonate, or the like is usually used.
• a physical gel electrolyte or a chemical gel electrolyte is generally known.
• the former is a solidification technique using non-covalent bonds such as hydrogen bonds and van der Waals forces, while the latter is a gelation method by a chemical reaction utilizing the formation of a polymer compound.
• the electrolyte when the electrolyte is gelled, the ionic conductivity decreases. That is, in the gel electrolyte, the interface resistance between the active material surface and the electrolyte is inevitably increased as compared with a normal electrolytic solution. As a result, even a slight deterioration of the surface of the active material significantly increases the electrode resistance, which in turn may cause a significant deterioration of the charge / discharge characteristics of the electricity storage device.
• a solution containing a gel electrolyte forming agent and an electrolyte is placed in a housing in which electrodes and separators are arranged, as in the conventional manufacturing process of a nonaqueous electrolyte type electricity storage device.
• the chemical gel electrolyte is usually produced by an irreversible chemical reaction by heating and / or irradiating light with a gel electrolyte forming agent containing a gel electrolyte prepolymer.
• a gel electrolyte forming agent containing a gel electrolyte prepolymer since the reactivity of the gel electrolyte prepolymer is very high, gelation may have already progressed when an attempt was made to produce the gel electrolyte. Therefore, it has been an issue to suppress the reaction of the gel electrolyte prepolymer and ensure the storage stability of the gel electrolyte forming agent.
• the present invention provides a gel electrolyte forming agent capable of producing a gel electrolyte with improved electrolyte retention.
• some embodiments according to the present invention provide a gel electrolyte forming agent that further improves storage stability.
• the present invention has been made to solve at least a part of the above-described problems, and can be realized as the following aspects or application examples.
• One aspect of the gel electrolyte forming agent according to the present invention is: A repeating unit (A1) derived from (meth) acrylate having a cyclic ether structure and a repeating unit (A2) derived from (meth) acrylate having a chain ether structure,
• a repeating unit (A1) derived from (meth) acrylate having a cyclic ether structure and a repeating unit (A2) derived from (meth) acrylate having a chain ether structure When the total amount of the repeating unit (A1) and the repeating unit (A2) is 100 [mol%], the amount of the repeating unit (A2) relative to the amount of the repeating unit (A1) (M1 [mol%])
• the polymer (A) contains a ratio (M2 / M1) of the amount (M2 [mol%]) in the range of 1 to 10.
• the (meth) acrylate having the cyclic ether structure may be a compound represented by the following general formula (1).
• R 1 represents a hydrogen atom or a methyl group
• R 2 represents a divalent linking group
• R 3 represents a hydrogen atom or a monovalent organic group
• a plurality of R 4 s are present.
• Independently represents a hydrogen atom or a monovalent organic group
• m and n are integers of 0 or more, and m + n ⁇ 1.
• the (meth) acrylate having a chain ether structure may be a compound represented by the following general formula (2).
• R 5 represents a hydrogen atom or a methyl group
• R 6 represents a single bond or a divalent organic group
• a plurality of R 7 s may be independently a divalent hydrocarbon group
• R 8 represents a hydrogen atom or a monovalent organic group
• x is an integer of 1 or more.
• the M1 [mol%] may be in the range of 10 to 40 mol%.
• the number average molecular weight of the polymer (A) may be 1,000 or more and 100,000 or less.
• the gel electrolyte forming agent according to any one of Application Examples 1 to 5 may further contain an ester compound (B) having at least one carbon-carbon unsaturated bond.
• the component (B) may be at least one selected from the group consisting of cyclic carbonates and (meth) acrylates.
• the cyclic ester carbonate may be a compound represented by the following general formula (3).
• R 12 and R 13 are each independently a hydrogen atom, a halogen atom, an alkyl or alkenyl group having 1 to 6 carbon atoms, or a phenyl group.
• the M A parts by mass content of the component (A), the content of the component (B) is taken as M B parts by weight,
• the ratio (M A / M B ) can be in the range of 1-100.
• the gel electrolyte forming agent of any one of Application Examples 1 to 5 may further contain a compound (C) having a phenolic hydroxyl group.
• the component (C) may be a compound represented by the following general formula (4).
• R 14 represents a substituted or unsubstituted alkyl group or alkoxy group.
• N is an integer of 0 or more and 5 or less.
• the component (C) may be a compound represented by the following general formula (5).
• R 15 represents a substituted or unsubstituted alkyl group or alkoxy group.
• M is an integer of 0 or more and 3 or less.
• the component (C) may be a compound having at least one group represented by the following general formula (6).
• R 16 and R 17 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.
• the ratio (M A / M C ) can be in the range of 10 to 1000.
• composition for forming a gel electrolyte according to the present invention contains the gel electrolyte forming agent of any one of Application Examples 1 to 14, and the liquid medium (D).
• the gel electrolyte forming composition of Application Example 15 may further contain a cyclic ether compound.
• the cyclic ether compound may have a cyclic ether group having a number of members different from that of the cyclic ether group contained in the (meth) acrylate having the cyclic ether structure.
• One aspect of the gel electrolyte according to the present invention is characterized by being produced by heating the gel electrolyte forming composition of any one of Application Examples 15 to 17.
• One aspect of the electricity storage device according to the present invention is characterized by including the gel electrolyte of Application Example 18.
• a gel electrolyte having sufficient ionic conductivity for developing good charge / discharge characteristics and having improved liquid retention compared to a conventional gel electrolyte Obtainable.
• storage stability becomes very favorable further.
• the gel electrolyte according to the present invention has good liquid retention, separation between the gel electrolyte matrix and the liquid medium can be suppressed. Further, since gelation can be performed under mild conditions, it is possible to suppress deterioration of the electrode and the gel electrolyte itself, and as a result, it is possible to suppress deterioration of charge / discharge characteristics of the electricity storage device. Furthermore, according to the electricity storage device including the gel electrolyte according to the present invention, the electricity storage device characteristics such as discharge rate characteristics, low temperature characteristics, DC-IR characteristics, and cycle characteristics are improved.
• (meth) acryl is a concept encompassing both “acryl” and “methacryl”.
• ⁇ (meth) acrylate is a concept encompassing both “ ⁇ acrylate” and “ ⁇ methacrylate”.
• the gel electrolyte forming agent includes a repeating unit (A1) derived from (meth) acrylate having a cyclic ether structure and a repeating unit derived from (meth) acrylate having a chain ether structure. (A2), and when the total amount of the repeating unit (A1) and the repeating unit (A2) is 100 [mol%], the amount of the repeating unit (A1) (M1 [mol%])
• the polymer (A) has a ratio (M2 / M1) of the amount (M2 [mol%]) of the repeating unit (A2) to 1) in the range of 1 to 10.
• the gel electrolyte forming agent according to the present embodiment is obtained by heating a gel electrolyte forming composition obtained by mixing with a liquid medium (D) and other additives described below under mild conditions. Can be produced.
• “heating under mild conditions” means heating at a temperature of about 70 to 100 ° C. at which the electrode and gel electrolyte do not deteriorate.
• the gel electrolyte is a highly flexible gel and has no thermoreversibility. Therefore, abnormal expansion of the battery due to heating or overcharging can be prevented, and workability such as thin film processing is improved.
• each component that may be included in the gel electrolyte forming agent according to the present embodiment will be described in detail.
• the polymer (A) contained in the gel electrolyte forming agent according to the present embodiment includes a repeating unit (A1) derived from a (meth) acrylate having a cyclic ether structure and a (meth) acrylate having a chain ether structure. Derived repeating unit (A2).
• the repeating unit (A1) is derived from (meth) acrylate having a cyclic ether structure.
• the repeating unit (A1) can construct a crosslinked structure by opening the cyclic ether structure when producing a gel electrolyte.
• the (meth) acrylate having a cyclic ether structure is not particularly limited as long as the cyclic ether structure can be opened and crosslinked, and is preferably a compound represented by the following general formula (1).
• R 1 represents a hydrogen atom or a methyl group
• R 2 represents a divalent linking group
• R 3 represents a hydrogen atom or a monovalent organic group
• a plurality of R 4 s are present.
• m and n are integers of 0 or more, and m + n ⁇ 1.
• R 1 represents a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoint of the oxidation resistance of the polymer (A).
• R 2 represents a divalent linking group, for example, a single bond, a divalent chain hydrocarbon group having 1 to 20 carbon atoms, a divalent cyclic saturated group having 3 to 20 carbon atoms, or An unsaturated hydrocarbon group, or a divalent group obtained by combining these with an ether group, an ester group, or a carbonyl group can be given.
• a divalent linking group may have a substituent. Is preferably a single bond or an alkylene group having 1 to 4 carbon atoms.
• R 3 represents a hydrogen atom or a monovalent organic group, and the monovalent organic group is preferably a linear or branched alkyl group having 1 to 8 carbon atoms.
• the linear or branched alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a 2-methylpropyl group, and a 1-methylpropyl group.
• R 3 is preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms so that it can be easily crosslinked.
• a plurality of R 4 each independently represents a hydrogen atom or a monovalent organic group, and the monovalent organic group is a linear or branched alkyl group having 1 to 4 carbon atoms.
• the linear or branched alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, and 1-methylpropyl group. And t-butyl group.
• each R 4 is independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms so that it can be easily crosslinked.
• M and n are integers of 0 or more, and m + n ⁇ 1, but they can be easily reacted, and the stability of the polymer is good. Therefore, in the above formula (1), m + n is 2 or more. And m + n is more preferably 2.
• the (meth) acrylate having the cyclic ether structure is more preferably a compound represented by the following general formula (1-1).
• the repeating unit derived from the compound represented by the following general formula (1-1) can be easily ring-opened and cross-linked with lithium ions in a non-aqueous solvent. Therefore, for example, when a gel electrolyte is prepared using the gel electrolyte forming composition containing the gel electrolyte forming agent of the present invention, lithium ions are contained as the liquid medium (D) contained in the gel electrolyte forming composition. By using such a liquid medium, the gel electrolyte forming agent can be easily cross-linked, and a gel electrolyte excellent in ion conductivity can be produced.
• the heat treatment of the gel electrolyte forming composition is not essential for producing the gel electrolyte, but from the viewpoint of producing a gel electrolyte with good gel strength, the heat treatment should be performed at a low temperature that does not deteriorate the active material. Is preferred.
• R 1 represents a hydrogen atom or a methyl group
• R 9 represents a single bond or a divalent organic group
• R 3 represents a hydrogen atom or a monovalent organic group
• each R 4 independently represents a hydrogen atom or a monovalent organic group.
• R 1 , R 3 and R 4 have the same meaning as in the above formula (1).
• R 9 represents a single bond or a divalent organic group, and examples of the divalent organic group include an alkylene group having 1 to 10 carbon atoms. Among these, R 9 is preferably a methylene group.
• the gel electrolyte produced by using the gel electrolyte-forming composition produced by mixing the gel electrolyte-forming agent according to the present embodiment and the liquid medium (D) described later is a cyclic unit of the repeating unit (A1). Since the ether structure is ring-opened and crosslinked, a strong polymer network structure can be constructed and a gel electrolyte having excellent gel strength can be obtained.
• the (meth) acrylate having a cyclic ether structure examples include glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate, (3-oxetanyl) methyl (meth) acrylate, (3-Methyl-3-oxetanyl) methyl (meth) acrylate, (3-ethyl-3-oxetanyl) methyl (meth) acrylate, (3-butyl-3-oxetanyl) methyl (meth) acrylate, (3-hexyl- 3-Oxetanyl) methyl (meth) acrylate, (3-ethyl-oxetane-3-yloxy) ethyl (meth) acrylate, (3-ethyl-oxetane-3-yloxy) butyl (meth) acryl
• the content of the repeating unit (A1) in the polymer (A) is such that when the total amount of the repeating unit (A1) and the repeating unit (A2) is 100 mol%, the repeating unit (A1) is 10 to 40 mol%. It is preferably 15 to 35 mol%.
• the content ratio of the repeating unit (A1) in the polymer (A) is in the above range, it is easy to heat under mild conditions using a metal ion such as lithium ion contained in the liquid medium (D) as a catalyst.
• a gel electrolyte can be produced without causing a deterioration of the coexisting electrode or liquid medium by causing a crosslinking reaction (cationic polymerization). Moreover, since it can also fully bridge
• the gel electrolyte forming agent according to the present embodiment does not require such an additive and can be gelled only by heating, it is possible to suppress the deterioration over time of the charge / discharge characteristics as described above. Is excellent.
• the repeating unit (A2) is derived from (meth) acrylate having a chain ether structure. Since the repeating unit (A2) has a (poly) ether-type chain ether structure moiety, the affinity with the liquid medium used for the electricity storage device can be improved. Thereby, liquid retention property can be provided to a polymer (A).
• the presence of a (poly) ether-type chain ether structure site degrades due to degradation due to a change in oxidation-reduction potential that accompanies charge / discharge of the electricity storage device. It is difficult to do.
• the polymer (A) having the repeating unit (A1) and the repeating unit (A2) it is possible to suppress deterioration due to a change in oxidation-reduction potential accompanying charging / discharging of the electricity storage device, and to maintain the gel electrolyte. Liquid deterioration can also be suppressed.
• the (meth) acrylate having a chain ether structure is preferably a compound represented by the following general formula (2).
• R 5 represents a hydrogen atom or a methyl group
• R 6 represents a single bond or a divalent organic group
• a plurality of R 7 s may be independently a divalent hydrocarbon group
• R 8 represents a hydrogen atom or a monovalent organic group
• x is an integer of 1 or more.
• R 5 represents a hydrogen atom or a methyl group, and is preferably a hydrogen atom from the viewpoint of synthesizing a polymer with good yield.
• R 6 represents a single bond or a divalent organic group, and the divalent organic group is preferably an alkylene group having 1 to 10 carbon atoms.
• a plurality of R 7 which may be present each independently represent a divalent hydrocarbon group, and the divalent hydrocarbon group includes a linear or branched 2 having 1 to 10 carbon atoms. Valent hydrocarbon group. Among these, it is preferable that each R 7 is independently an alkylene group having 1 to 3 carbon atoms because of high affinity with a liquid medium.
• R 8 represents a hydrogen atom or a monovalent organic group, and the monovalent organic group is a linear or branched alkyl group having 1 to 4 carbon atoms, or a group having 6 to 12 carbon atoms.
• An aryl group is preferred. Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include those exemplified in the description of R 4 above. Examples of the aryl group include a phenyl group and a naphthyl group.
• R 8 is preferably an alkyl group having 1 to 3 carbon atoms because of high affinity with the liquid medium.
• x is an integer of 1 or more, preferably 1 to 30, more preferably 1 to 20, and particularly preferably 1 to 10.
• the (meth) acrylate having a chain ether structure is more preferably a compound represented by the following general formula (2-1).
• the repeating unit derived from the compound represented by the following general formula (2-1) has a high affinity with a carbonate-based solvent or a lactone-based polymer generally used in non-aqueous electrolytes, and is crosslinked to form a polymer.
• a strong network is formed, the nonaqueous electrolyte solution can be absorbed and sufficiently swelled, and movement of lithium ions between the nonaqueous electrolyte solution and the active material is not hindered.
• a gel electrolyte that exhibits good ionic conductivity can be produced.
• R 5 represents a hydrogen atom or a methyl group
• R 10 represents a single bond or a divalent organic group
• a plurality of R 11 are each independently a hydrogen atom or a monovalent organic group.
• R 8 represents a hydrogen atom or a monovalent organic group.
• R 5 has the same meaning as R 5 in the general formula (2).
• R 8 has the same meaning as R 8 in the general formula (2).
• R 10 represents a single bond or a divalent organic group, and examples of the divalent organic group include an alkylene group having 1 to 10 carbon atoms. Among these, R 10 is preferably a single bond.
• a plurality of R 11 each independently represent a hydrogen atom or a monovalent organic group, and the monovalent organic group is preferably a linear or branched alkyl group having 1 to 4 carbon atoms.
• the linear or branched alkyl group having 1 to 4 carbon atoms include those exemplified in the description of R 4 above.
• each of R 11 is preferably a hydrogen atom since affinity with the liquid medium (D) is increased.
• x is an integer of 1 or more, preferably 1 to 30, more preferably 1 to 20, and particularly preferably 1 to 10.
• Specific examples of the compound represented by the general formula (2) include 2-methoxyethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, and 2-ethylhexyloxydiethylene glycol (meth).
• the content of the repeating unit (A2) in the polymer (A) is such that when the total amount of the repeating unit (A1) and the repeating unit (A2) is 100 mol%, the repeating unit (A2) is 60 to 90 mol%. It is preferably some 65 to 85 mol%.
• the content ratio of the repeating unit (A2) in the polymer (A) is in the above range, a gel electrolyte having excellent oxidation-reduction resistance and excellent liquid retention can be produced.
• the polymer (A) contained in the gel electrolyte forming agent according to this embodiment has a total amount of 100 mol of the repeating unit (A1) and the repeating unit (A2). %,
• the ratio (M2 / M1) of the amount (M2 [mol%]) of the repeating unit (A2) to the amount (M1 [mol%]) of the repeating unit (A1) is in the range of 1 to 10 It is preferably in the range of 1.5 to 8, more preferably in the range of 2 to 6.
• Polymer (A) contained in the gel electrolyte forming agent according to the present embodiment starts radical polymerization of (meth) acrylate having a cyclic ether structure and (meth) acrylate having a chain ether structure. It can be easily prepared by radical (co) polymerization in a reaction solvent in the presence of an agent and optionally a molecular weight regulator.
• the polymer (A) thus obtained is a copolymer, it may have any structure of a random copolymer, an alternating copolymer, a periodic copolymer, and a block copolymer.
• reaction solvent water, alcohol, ester, carbonate, ketone, lactone, ether, sulfoxide, amide etc.
• examples of the alcohol include methanol, ethanol, isopropanol and the like
• examples of the ester include ethyl acetate, methyl propionate, and butyl acetate
• Examples of the carbonate include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate
• the ketone include methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and diethyl ketone
• Examples of the lactone include ⁇ -butyl lactone
• Examples of the ether include trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofur
• the reaction solvent is preferably at least one solvent that can be contained in the liquid medium (D) exemplified later, and more preferably the same solvent as the solvent actually used in the gel electrolyte forming composition. .
• the gel electrolyte-forming agent solution after polymerization can be directly used for the preparation of the gel electrolyte-forming composition, thus simplifying the process. be able to. In this case, it is possible to produce a gel electrolyte having better liquid retention by radical polymerization using a solvent that can be contained in the liquid medium (D) as a reaction solvent.
• the affinity between the resulting polymer and the liquid medium (D) becomes very good. Preparation of the composition for use is facilitated, and liquid retention of the resulting gel electrolyte is very good.
• the liquid medium (D) will be described later.
• the reaction solvent it is preferable to use one or more selected from carbonates, lactones, ethers and sulfoxides. Among these, the liquid medium actually used or a mixture thereof is used. Most preferably it is used. Surprisingly, it has been revealed that the effect of improving the liquid retention is maintained even when the solvent is replaced after the polymerization in the reaction solvent.
• the ratio of the solvent used in the production of the polymer (A) is preferably 100 to 1,000 parts by mass, and preferably 200 to 500 parts by mass with respect to 100 parts by mass of the total amount of monomers. More preferred.
• radical polymerization initiator In the radical (co) polymerization, a radical polymerization initiator is usually used.
• the radical polymerization initiator include azo initiators such as N, N′-azobisisobutyronitrile and dimethyl N, N′-azobis (2-methylpropionate); benzoyl peroxide, lauroyl peroxide And organic peroxide initiators such as
• the radical polymerization initiator is preferably added in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of all monomers.
• the molecular weight regulator examples include halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptan compounds such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dotezyl mercaptan, and thioglycolic acid; dimethyl
• halogenated hydrocarbons such as chloroform and carbon tetrachloride
• mercaptan compounds such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dotezyl mercaptan, and thioglycolic acid
• dimethyl examples thereof include xanthogen compounds such as xanthogen disulfide and diisopropylxanthogen disulfide; and other molecular weight regulators
• the polymer (A) is a radical (co) polymerization using a monomer other than the compound represented by the general formula (1) or (2) (hereinafter also referred to as “other monomer”).
• the content of other monomers in 100 mol% of all monomers is preferably less than 10 mol%, and more preferably 0 mol%.
• the number average molecular weight (Mn) of the polymer (A) obtained as described above is preferably 1,000 to 1,000,000, more preferably 1,000 to 100,000, and 10,000 to 100,000. Is particularly preferred.
• the number average molecular weight (Mn) of the polymer (A) is 100,000 or less, the impregnation property to the electrode plate is improved, so that the electrical characteristics (charge rate characteristics, DC-IR characteristics, cycle characteristics) of the obtained electricity storage device are obtained. ) Tend to be better.
• the number average molecular weight (Mn) of the polymer (A) is 1000 or more and 100,000 or less, the cycle characteristics of the obtained electricity storage device tend to be particularly good.
• the number average molecular weight (Mn) of a polymer (A) can be calculated
• the gel electrolyte forming agent according to the present embodiment may contain an ester compound (B) having at least one carbon-carbon unsaturated bond (hereinafter also referred to as “component (B)”).
• component (B) is also contained in the gel electrolyte produced using this gel electrolyte forming agent.
• an electrode including a gel electrolyte containing such a component (B) it is considered that when a charge / discharge is started, the component (B) undergoes electropolymerization to form a protective film on the surface of the active material layer.
• Such a protective film is a stable film that does not crack during the charge / discharge cycle of the battery, and the active material surface is covered with the protective film, so that the liquid medium is decomposed and gas is generated by repeated charge / discharge. Therefore, it is considered that the charge / discharge characteristics of the electricity storage device can be improved.
• dendrites due to metal ions are likely to occur on the electrode surface by repeated charge and discharge. Since such dendrites are usually precipitated as needle-like crystals, when the crystals grow, they are short-circuited with the counter electrode and lose the charge / discharge function.
• the protective film described above also has an effect of suppressing the growth of dendrites on the electrode surface, and as a result, the charge / discharge characteristics of the electricity storage device can be improved.
• the content of component (B) in the gel electrolyte-forming agent according to the present embodiment M A parts by weight and the content of the polymer (A), the content of the component (B) was M B parts by weight
• the ratio (M A / M B ) is preferably in the range of 1-100.
• the gelation is not inhibited when the gel electrolyte is produced from the gel electrolyte forming agent, and the surface of the active material layer is appropriately protected as described above. Since a film can be formed, deterioration of the active material layer surface can be suppressed. This improves the cycle characteristics of the electricity storage device.
• the interface resistance between the gel electrolyte and the active material layer surface can be reduced by an appropriate protective film formed on the surface of the active material layer, an electricity storage device having good charge / discharge characteristics is manufactured. Can do.
• the component (B) is not limited as long as it is an ester having at least one carbon-carbon unsaturated bond, but it does not have solubility in the liquid medium (D) described later or phase separation from the polymer (A). From the viewpoint of producing a uniform gel electrolyte, it is preferably at least one selected from the group consisting of cyclic carbonates and (meth) acrylates. Hereinafter, the cyclic carbonate and (meth) acrylate will be described in this order.
• Cyclic carbonate examples include compounds represented by the following general formula (3).
• R 12 and R 13 are each independently a hydrogen atom, a halogen atom, an alkyl or alkenyl group having 1 to 6 carbon atoms, or a phenyl group. Note that when R 12 or R 13 is an alkyl group, an alkenyl group, or a phenyl group, part of the hydrogen atoms may be substituted with a halogen atom (preferably a fluorine atom).
• cyclic carbonate examples include vinylene carbonate (VC), 3-methyl vinylene carbonate, 3,4-dimethyl vinylene carbonate, 3-ethyl vinylene carbonate, 3,4-diethyl vinylene carbonate, 3-propyl vinylene carbonate, 3 , 4-dipropyl vinylene carbonate, 3-phenyl vinylene carbonate, 3,4-diphenyl vinylene carbonate, vinyl ethylene carbonate (VEC), divinyl ethylene carbonate (DVEC), fluorinated vinylene carbonate, and the like.
• VC vinylene carbonate
• VEC vinyl ethylene carbonate
• DVEC divinyl ethylene carbonate
• fluorinated vinylene carbonate and the like.
• At least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, and divinyl ethylene carbonate is preferable, and vinylene carbonate is particularly preferable from the viewpoint of efficiently forming a protective film on the surface of the active material layer.
• the content ratio of the component (B) in the gel electrolyte forming agent is such that the concentration of the cyclic carbonate in the gel electrolyte forming composition described later is 0.5 to 5.
• the content is preferably 0% by mass, more preferably 0.5 to 4.0% by mass, and particularly preferably 0.5 to 3.0% by mass.
• (meth) acrylate (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, n-amyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) Alkyl (meth) acrylates such as acrylate and decyl (meth) acrylate; 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, ethylene glycol di (meth) acrylate;
• the content ratio of component (B) in the gel electrolyte forming agent is such that the concentration of (meth) acrylate in the gel electrolyte forming composition described later is 0.01 to
• the content is preferably 5.0% by mass, more preferably 0.01 to 4.0% by mass, and particularly preferably 0.05 to 2.0% by mass.
• (meth) acrylates as exemplified above are likely to volatilize when heated, when preparing a gel electrolyte by heating a composition for forming a gel electrolyte containing (meth) acrylate, (meth) In some cases, the acrylate is vaporized to generate gas, and the housing of the electricity storage device is deformed. However, it is preferable that the concentration of (meth) acrylate is within the above-mentioned range because the generation of such gas can be effectively suppressed.
• the gel electrolyte forming agent according to the present embodiment may contain a compound (C) having a phenolic hydroxyl group (hereinafter also referred to as “component (C)”).
• component (C) a compound having a phenolic hydroxyl group
• the “phenolic hydroxyl group” means a hydroxyl group directly bonded to an aromatic ring such as a benzene ring, a condensed benzene ring, a non-benzene aromatic ring or a heteroaromatic ring.
• the crosslinking reaction may proceed at a cyclic ether structure contained in the polymer (A) or a different site. .
• a part of gel electrolyte formation agent gelatinizes and the storage stability of a gel electrolyte formation agent falls.
• the storage stability is improved because the crosslinking reaction by the polymerization initiator of the gel electrolyte forming composition produced using the gel electrolyte forming agent can be suppressed. To do. Therefore, in an actual production line, since it can supply stably, without changing the characteristic of the composition for gel electrolyte formation, the gel electrolyte with stable quality can be supplied.
• component (C) does not deteriorate the charge / discharge characteristics of the electricity storage device.
• the reason for this is not fully elucidated and is not preferred to be bound by theory, but in an electrode equipped with such a gel electrolyte, when charge / discharge is first performed, the component (C) undergoes electropolymerization, It is thought that a protective film is formed on the surface of the active material layer. By forming such a protective film, it is considered that decomposition of the liquid medium can be suppressed.
• Such a protective film is a stable film that does not crack during the charge / discharge cycle of the battery, and the surface of the active material layer is covered with the protective film, so that the liquid medium is decomposed or the gas is removed by repeated charge / discharge. Since generation
• the protective film described above also has an effect of suppressing the growth of dendrites on the electrode surface, and as a result, the charge / discharge characteristics of the electricity storage device can be improved.
• the content ratio of the component (C) is within the above range, not only can the storage stability of the gel electrolyte forming agent be ensured, but also the solubility in the liquid medium (D) described later, This is preferable in that a more uniform gel electrolyte can be produced without phase separation with the coalescence (A).
• the component (C) is preferably a compound represented by the following general formula (4).
• R 14 represents a substituted or unsubstituted alkyl group or alkoxy group.
• N is an integer of 0 or more and 5 or less.
• a plurality of R 14 which may be present each represents a substituted or unsubstituted alkyl group or alkoxy group.
• the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms).
• Such alkyl groups may be linear, branched or cyclic, such as methyl, ethyl, propyl, isopropyl, butyl, secondary butyl, tertiary butyl, isobutyl.
• R 14 is an alkyl group, it is preferable that an alkyl group is substituted at the 2-position and / or the 6-position of the phenol group because the effect of improving the storage stability of the gel electrolyte forming agent is high.
• an alkoxy group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms) is preferable.
• alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentoxy, hexyloxy, heptyloxy, octyloxy, isooctyloxy, nonyloxy, decyloxy, and the like.
• R 14 is an alkoxy group, it is preferable that an alkoxy group is substituted at the 4-position of the phenol group because the effect of improving the storage stability of the gel electrolyte forming agent is high.
• the compound represented by the following general formula (5) is more effective in improving the storage stability of the gel electrolyte forming agent. It is more preferable that (In Formula (5), R 15 represents a substituted or unsubstituted alkyl group or alkoxy group. M represents an integer of 0 or more and 3 or less.)
• a plurality of R 15 which may be present each represent a substituted or unsubstituted alkyl group or alkoxy group.
• the alkyl group is preferably an alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), and examples thereof include the same alkyl group as R 14 in the above formula (4).
• the alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), and examples thereof include the same alkoxy groups as R 14 in the above formula (4).
• Specific examples of the compound represented by the general formula (4) include 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, 2,4 , 6-tri-t-butylphenol, 2,6-di-t-butyl-4-s-butylphenol, 2,6-di-t-butyl-4-methoxyphenol, 2,6-di-t-butyl- 4-hydroxymethylphenol, 2,6-di-t-butyl-4- (methoxycarbonyl) phenol, 2,6-di-t-butyl-4-nonylphenol, 4-methoxyphenol, 4-ethoxyphenol, 4- Examples include propoxyphenol, 4-isopropoxyphenol, 4-butoxyphenol, 4-t-butoxyphenol and the like.
• component (C) a compound having at least one group represented by the following general formula (6) (hydroxyphenylpropionate compound), hydroxybenzyl compound, thiobisphenol compound, thiomethylphenol compound An alkanediylphenol compound is also preferred.
• R 16 and R 17 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, but an alkyl having 1 to 6 carbon atoms (more preferably 1 to 4 carbon atoms). It is preferably a group.
• the alkyl group may be any of linear, branched and cyclic, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, secondary butyl group, tertiary butyl group, isobutyl group, amyl Group, tertiary amyl group, cyclopentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, isooctyl group, tertiary octyl group, 2-ethylhexyl group, nonyl group, decyl group and the like.
• hydroxyphenylpropionate compounds include 3,9-bis [2- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethoxy. ] -2,4,8,10-terolaoxaspiro [5.5] undecane, pentaerythrityltetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol- Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadec -[3- (3,5-di-tert-butyl-4-hydroxyphen
• hydroxybenzyl compounds include 1,3,5, -trimethyl-2,4,6, -tris (3 ′, 5′-di-t-butyl-4-hydroxybenzyl) benzene, 1,3 , 5-tris (4-hydroxybenzyl) benzene, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, 1,3,5-tris (4-tert-butyl-3) -Hydroxy-2,6-dimethylbenzyl) -isocyanurate and the like.
• thiobisphenol compound examples include 4,4′-thiobis (6-tert-butyl-3-methylphenol).
• thiomethylphenol compound examples include 2,4-bis [(octylthio) methyl] -o-cresol.
• alkanediylphenol compounds include N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), 2,2′-methylenebis (4-methyl).
• -6-tert-butylphenol 4,4'-butylidene-bis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) ) Butane and the like.
• the component (C) contained in the gel electrolyte forming agent according to the present embodiment preferably has a standard boiling point of 100 to 250 ° C.
• the standard boiling point is within the above range, vaporization of the component (C) can be suppressed in the step of heating when producing the gel electrolyte. That is, even if gelation is performed by heating in a state where the casing is sealed in the power storage device manufacturing process, deformation due to an increase in the casing internal pressure due to gas generation can be suppressed.
• composition for gel electrolyte formation according to the present embodiment (hereinafter also simply referred to as “composition”) contains the above-described gel electrolyte formation agent and the liquid medium (D). .
• composition contains the above-described gel electrolyte formation agent and the liquid medium (D). .
• the above-mentioned gel electrolyte forming agent and other additives as necessary are added to the liquid medium (D) and heated to about 40 to 60 ° C. It is sufficient to stir well. Thereby, the polymer (A) contained in the gel electrolyte forming agent can be completely dissolved in the liquid medium (D). Note that if the heating temperature is raised to 70 to 100 ° C., a gel electrolyte may be formed.
• the composition according to the present embodiment is stable around room temperature and does not gel. For this reason, since it can be set as a gel electrolyte by inject
• omitted the storage stability and the freedom degree of an electrical storage device preparation process.
• Liquid medium (D) The liquid medium (D) contained in the composition according to the present embodiment further contains an electrolyte, a solvent for dissolving the electrolyte, and, if necessary, an additive.
• any conventionally known lithium salts can also be used, and specific examples LiClO 4, LiBF 4, LiPF 6 , LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, LiCF 3 SO 3, LiCH 3 SO 3, LiC 4 F 9 SO 3, Li (CF 3 SO 2) 2 N, a lower fatty acid Lithium etc. can be illustrated.
• These electrolytes may be used alone or in combination of two or more.
• an electrolyte other than Li examples include (FSO 2 ) 2 N ⁇ , BF 4 ⁇ , PF 6 ⁇ , SbF 6 ⁇ , NO 3 ⁇ , CF 3 SO 3 ⁇ , (CF 3 SO 2 ) 2 N ⁇ , ( Anions such as C 2 F 5 SO 2 ) 2 N ⁇ , (CF 3 SO 2 ) 3 C ⁇ , CF 3 CO 2 ⁇ , C 3 F 7 CO 2 ⁇ , CH 3 CO 2 ⁇ , (CN) 2 N ⁇ And a salt composed of a combination of cation and cation.
• any one of N, P, S, O, C, and Si or two or more kinds of elements are included in the structure, and a chain structure or a cyclic structure such as a 5-membered ring or a 6-membered ring is included in the skeleton.
• Compounds. Examples of the compound having a chain structure in the skeleton include alkyl ammonium.
• Examples of compounds having a cyclic structure in the skeleton include furan, thiophene, pyrrole, pyridine, oxazole, isoxazole, thiazol, isothiazol, furazane, imidazole, pyrazole, pyrazine, pyrimidine, pyridazine, pyrrolidine, Heterocyclic compounds such as piperidine; and condensed heterocyclic compounds such as benzofuran, isobenzofuran, indole, isoindole, isodridine, and carbazole.
• lithium ions act as a cationic polymerization initiator, which is preferable in that it is not necessary to use another cationic polymerization initiator.
• LiPF 6 it is particularly preferable in that the discharge capacity retention rate at a low temperature of the obtained electricity storage device is good.
• Solvents for dissolving the electrolyte include ethylene carbonate (EC), dimethyl carbonate (DMC), propylene carbonate (PC), methyl ethyl carbonate (MEC), methyl propyl carbonate (PMC), butylene carbonate (BC), diethyl Carbonates such as carbonate (DEC); cyclic carboxylic acid esters such as ⁇ -butyrolactone (GBL) and ⁇ -valerolactone; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, methyl Cyclic ethers such as tetrahydrofuran and methyltetrahydrofuran; sulfolane and the like can be used. These solvents may be used alone or in combination of two or more.
• Such a liquid medium (D) usually has an electrolyte concentration of 0.1 to 5 mol / L, particularly preferably 0.5 to 2 mol / L.
• additives examples include additives conventionally used in electrolyte solutions, and specifically, components for improving ionic conductivity can be used.
• nitrogen-containing or sulfur-containing compounds such as azaindole, benzimidazole, benzodithiol, benzofuran, benzothiazole, 1-benzothiophene, 1H-benzotriazole, benzylcapton, 1-bromo-3-fluorobenzene; sucrose fatty acid
• ester examples include 10 mass% or less, preferably 3 mass% or less.
• these additives may be used individually by 1 type, and may be used in combination of 2 or more types.
• the composition for forming a gel electrolyte according to the present embodiment may be further added with a cyclic ether compound from the viewpoint of improving the liquid retention of the resulting gel electrolyte and increasing the crosslink density to improve the mechanical strength.
• a cyclic ether compound those having an alkyl group having 6 to 28 carbon atoms are preferable, an alkyl glycidyl ether having an alkyl group having 6 to 28 carbon atoms, and a fatty acid glycidyl ether having an alkyl group having 6 to 28 carbon atoms. More preferred are alkylphenol glycidyl ethers having an alkyl group having 6 to 28 carbon atoms.
• alkyl glycidyl ethers having an alkyl group having 6 to 28 carbon atoms are particularly preferable.
• these cyclic ether compounds may be used individually by 1 type, and 2 or more types may be mixed and used for them.
• the cyclic ether compound preferably has two or more cyclic ether groups in the molecule.
• the crosslink density can be further increased, so that the mechanical strength of the gel electrolyte can be further improved.
• cyclic ether compounds include vinylcyclohexene dioxide, dicyclopentadiene dioxide, alicyclic diepoxy-adipade, 1,6-bis (2,3-epoxypropoxy) naphthalene, ethylene glycol diglycidyl ether.
• the cyclic ether compound When a cyclic ether compound is added to the gel electrolyte forming composition according to the present embodiment, the cyclic ether compound has a different number of members from the cyclic ether group contained in the repeating unit (A1) in the polymer (A). It preferably has a cyclic ether group.
• the cyclic ether group contained in the repeating unit (A1) is an oxiranyl group
• the cyclic ether compound to be added preferably has an oxetanyl group.
• the cyclic ether compound to be added when the cyclic ether group contained in the repeating unit (A1) is an oxetanyl group, the cyclic ether compound to be added preferably has an oxiranyl group.
• the cyclic ether compound added in this way has a different number of cyclic ether groups from the cyclic ether group contained in the repeating unit (A1), it can be more effectively cross-linked, and the gel electrolyte can be produced.
• the heating temperature can be further reduced. Thereby, the deterioration of the electrode and gel electrolyte itself accompanying heating can be suppressed.
• a crosslinking density can be improved, the gel electrolyte excellent in mechanical strength can be produced.
• the content of the cyclic ether compound is in the range of 0 to 50 parts by mass with respect to 100 parts by mass of the polymer (A). It is preferred that
• gel electrolyte The gel electrolyte which concerns on this Embodiment is produced by heating the above-mentioned composition for gel electrolyte formation. Since the gel electrolyte according to the present embodiment can be prepared simply by heating the above-described composition for forming a gel electrolyte, unlike a general gel electrolyte, a thermal acid generator or a light used for gel electrolyte preparation is used. An additive such as an acid generator may not be contained. For this reason, with the charge / discharge of the electricity storage device, it is possible to suppress the deterioration over time of the charge / discharge characteristics that may be caused by the decomposition of the thermal acid generator or the photoacid generator.
• the heating temperature in the preparation of the gel electrolyte can be set to 70 to 100 ° C. (preferably 75 to 95 ° C., more preferably 80 to 90 ° C.), the deterioration of the active material layer of the electricity storage device can be suppressed. Can do. Further, since the ring-opening and crosslinking are performed, the change in the volume of the polymer is small, and damage to the structure of the electricity storage device such as peeling of the active material layer can be suppressed even if the polymer is gelled in a sealed state.
• the gel electrolyte according to the present embodiment is a highly flexible gel and has no thermoreversibility. Therefore, abnormal expansion of the battery due to heating or overcharging can be prevented, and workability such as thin film processing is improved.
• Electric storage device The electric storage device according to the present embodiment may include a known configuration and material in addition to the gel electrolyte described above.
• the electrode material is not particularly limited as long as it can insert and desorb lithium ions.
• the electrode for example, an electrode in which a positive electrode / negative electrode active material layer is formed on the surface of a current collector can be used.
• the positive electrode active material examples include metal oxides such as CuO, Cu 2 O, MnO 2 , V 2 O 5 , CrO 3 , MoO 3 , Fe 2 O 3 , Ni 2 O 3 , and CuO 3 , and Li x CO 2. , Li x NiO 2 , Li x Mn 2 O 4 , LiFePO 4 and other complex oxides of lithium and transition metals, TiS 2 , MoS 2 , NbSe 3 and other metal chalcogenides, polyacene, polyparaphenylene, polypyrrole, Examples thereof include conductive compounds such as polyaniline.
• a composite oxide of lithium and one or more kinds selected from transition metals such as cobalt, nickel, manganese, and iron is preferable.
• transition metals such as cobalt, nickel, manganese, and iron
• These lithium composite oxides may be doped with a small amount of elements such as fluorine, boron, aluminum, chromium, zirconium, molybdenum, and iron.
• lithium storage metals such as metallic lithium, Al, Mg, Pt, Sn, Si, Zn, and Bi
• Al-based lithium alloys such as Al—Ni, Al—Ag, and Al—Mn
• SbSn Antimony type lithium alloys such as InSb, CoSb 3 , Mi 2 MnSb
• Sn 2 M (M Fe, Co, Mn, V, Ti)
• Sn-based lithium alloys such as 4 ; Sn oxides such as SnO 2 , Sn 2 P 2 O 7 , SnPBO 6 , SnPO 4 Cl; Si-based such as Si—C composite, Si—Ti composite, and Si—M thin film Lithium alloys; Nanocomposite materials such as Sn and Si; Amorphous alloy materials such as Sn, Co and Carbon; Sn-based plating alloys such as Sn-Ag and Sn-Cu; Si-based amorphous thin films
• carbon materials include amorphous carbon, mesocarbon microbeads, graphite, natural graphite, non-graphitizable carbon, and the like, and surface modified products of these carbon materials are preferable materials.
• a conductive agent may be used for the electrode material. Any conductive material that does not adversely affect battery performance can be used as the conductive agent. Normally, carbon black such as acetylene black and kettin black is used, but carbon fibers such as natural graphite, artificial graphite, carbon whisker, vapor grown carbon, carbon nanotubes, fullerene, conductive ceramic materials, etc. may be used. Often, these can be included as a mixture of two or more.
• the current collector is not particularly limited as long as it is an electronic conductor that does not adversely affect the constructed power storage device.
• Examples of the positive electrode current collector include aluminum, titanium, stainless steel copper, nickel, baked carbon, conductive polymer, conductive glass, etc., and aluminum and copper for the purpose of improving adhesion, conductivity, and oxidation resistance. Or the like can be used which have been treated with carbon, nickel, titanium, silver or the like.
• Examples of the negative electrode current collector include copper, stainless steel, nickel, aluminum, titanium, calcined carbon, conductive polymer, conductive glass, Al—Cd alloy, etc.
• a surface of copper or the like treated with carbon, nickel, titanium, silver or the like can be used.
• the surface of these current collector materials can be oxidized.
• As for these shapes in addition to a foil shape, a film shape, a sheet shape, a net shape, a punched or expanded material, a glass body, a porous body, a foamed body and the like are also used.
• a binder for binding the positive electrode / negative electrode active material to the current collector a copolymer of polyvinylidene fluoride and hexafluoropropylene (HFP), perfluoromethyl vinyl ether (PFMV) or tetrafluoroethylene (TFE)
• HFP polyvinylidene fluoride and hexafluoropropylene
• PFMV perfluoromethyl vinyl ether
• TFE tetrafluoroethylene
• Polyvinylidene fluoride copolymer resins such as polytetrafluoroethylene (PTFE), fluorine resins such as fluorine rubber; styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPDM), styrene-acrylonitrile copolymer, etc.
• polysaccharides such as carboxymethylcellulose (CMC) and thermoplastic resins such as polyimide resin, but are not limited thereto. Moreover, you may use these in mixture of 2 or more types.
• the addition amount is preferably 0.2 to 30 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the active material.
• the positive electrode active material whose surface is coated with carbon such as LiFePO 4
• a carboxylic acid-modified polyvinylidene fluoride or SBR aqueous binder can be mentioned as a preferable material.
• a porous membrane is used, and usually a porous polymer film or a nonwoven fabric is preferably used.
• a porous polymer film or a nonwoven fabric is preferably used.
• those composed of a non-conductive porous material and electrically insulating particles are particularly suitable.
• the non-conductive porous material is selected from polyacrylonitrile, polyester (PET), polyimide, polyamide, polytetrafluoroethylene, polyolefin, glass, ceramic and the like.
• PET polyester
• polyamide polytetrafluoroethylene
• polyolefin polyolefin
• glass glass
• ceramic ceramic
• a nonwoven fabric having an electrically insulating inorganic film on a flat flexible substrate is suitable, and polyester (PET) and polyamide are particularly preferred.
• the insulating particles used for the separator include at least one kind of inorganic oxide such as alumina, titania, silicon and / or zirconia as the inorganic material, and polymers such as fluororesin, polystyrene resin and acrylic resin as the organic material. Particles are used.
• the separator can further have a shutdown mechanism because the separator or the separator has an extremely thin wax particle layer or polymer particle layer that melts at a desired cutoff temperature.
• Materials that are advantageous for forming the barrier particles include low melting polymers such as natural or artificial waxes and polyolefins, which melt at the desired barrier temperature and close the pores of the separator. Further current during the abnormal operation of the battery can be suppressed.
• the electricity storage device can be formed in a cylindrical shape, a coin shape, a square shape, a laminate shape, or any other shape, and the basic configuration of the electricity storage device is the same regardless of the shape, depending on the purpose.
• the design can be changed.
• the above-mentioned composition for gel electrolyte formation You may heat-process, after injecting
• Example 1 5.1.1. Preparation of Gel Electrolyte Forming Agent
• 52 g of methoxyethyl acrylate (monomer content ratio: 74% by mass, equivalent to 80 mol%), 18 g of (3-ethyl-3-oxetanyl) methyl methacrylate (monomer content ratio) 26 mass%, corresponding to 20 mol%), 211 g of ethylene carbonate (EC): diethyl carbonate (DEC) 3: 7 (volume ratio) as a reaction solvent, and 0.2% of N, N′-azobisisobutyronitrile. 71 g (1 part by mass with respect to 100 parts by mass of monomer) was added, heated to 60 ° C.
• a gel electrolyte was prepared by filling 10 g of the obtained gel electrolyte forming composition into a 50 mL vial tube and heating in an oven at 80 ° C. for 30 minutes. The obtained gel electrolyte was allowed to stand at 25 ° C. for 1 day, and the appearance of the gel electrolyte was visually observed. Table 3 shows the evaluation results. In Tables 3 to 10, if the gel electrolyte matrix and the liquid medium are not separated, it is judged that the liquid retaining property is good and “ ⁇ ”, and if they are separated, the liquid retaining property is judged to be poor. ⁇ ”.
• Biaxial planetary mixer product name “TK Hibismix 2P-03” manufactured by PRIMIX Co., Ltd.
• binder for electrochemical device electrode product name “KF polymer # 1120” manufactured by Kureha Co., Ltd.
• conductive assistant manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “Denka Black 50% press product”
• LiCoO 2 having a particle diameter of 5 ⁇ m as a positive electrode active material (manufactured by Hayashi Kasei Co., Ltd.) ) 100 parts by mass (in terms of solid content) and 36 parts by mass of N-methylpyrrolidone (NMP) were added and stirred at 60 rpm for 2 hours.
• SBR binder composition manufactured by JSR Corporation, trade name “TRD2001”
• TRD2001 2 parts by mass of the SBR binder composition
• the mixture was further stirred at 60 rpm for 1 hour to obtain a paste.
• the mixture was stirred at 200 rpm for 2 minutes at 200 rpm using a stirring defoamer (trade name “Awatori Nertaro” manufactured by Shinky Co., Ltd.).
• a negative electrode slurry was prepared by stirring at 1,800 rpm for 5 minutes and further stirring at 1,800 rpm for 1.5 minutes under a reduced pressure of 25 kPa, followed by mixing.
• the negative electrode slurry prepared above was uniformly applied to the surface of a current collector made of copper foil having a thickness of 20 ⁇ m by a doctor blade method so that the film thickness after drying was 150 ⁇ m, and dried at 120 ° C. for 20 minutes. . Then, the negative electrode was obtained by pressing using a roll-press machine so that the density of a film
• a negative electrode terminal was attached to and mounted on the negative electrode cut out to 50 mm ⁇ 25 mm on a film-like exterior aluminum seal made of aluminum.
• a separator made of a polypropylene porous film cut out to 54 mm ⁇ 27 mm (manufactured by Celgard, trade name “Celguard # 2400”, thickness 25 ⁇ m) was placed on the negative electrode, and then cut into 48 mm ⁇ 23 mm.
• a positive electrode terminal was attached to the positive electrode and placed on the separator. And the exterior aluminum seal similar to the said exterior aluminum seal was mounted on this positive electrode.
• the laminated body which consists of an exterior aluminum seal, a negative electrode, a separator, a positive electrode, and an exterior aluminum seal was obtained. Thereafter, the outer peripheral aluminum seals on the three sides of this laminate were sealed by bonding the outer peripheral edges of the two outer aluminum seals with a heating sealing device. Then, after injecting the gel electrolyte forming composition obtained above so that air does not enter between each layer and further degassing under reduced pressure, the negative electrode terminal and the positive electrode terminal are external to the outer aluminum seal under reduced pressure. The 4th side was sealed so that it might be exposed, and it sealed. The laminated cell thus sealed was heated in an oven at 80 ° C. for 30 minutes to produce a secondary battery (electrochemical device) composed of a bipolar single-layer laminated cell.
• a secondary battery electrochemical device
• the discharge rate (%) was calculated by calculating the ratio (percent%) of the discharge capacity at 2C to the discharge capacity at 0.2C.
• the discharge rate of the secondary battery cell produced by using is “B”, it can be evaluated that the discharge rate characteristic represented by the following formula (7) is 0.7 or more. .
• Discharge rate characteristics A / B (7)
• Table 3 shows the obtained discharge rate characteristic values.
• “1C” indicates a current value at which discharge is completed in one hour after constant current discharge of a cell having a certain electric capacity.
• “0.1 C” is a current value at which discharge is completed over 10 hours
• 10 C is a current value at which discharge is completed over 0.1 hours.
• the discharge capacity retention rate (percentage%) at 0 ° C. with respect to the discharge capacity at 25 ° C. was used as an index of low temperature characteristics.
• the discharge capacity retention rate at 0 ° C. of the secondary battery cell produced using the electrolyte solution of (R) is “D”
• the low temperature characteristic represented by the following formula (8) is 0.8 or more. If it exists, it can be evaluated that it is favorable. Table 3 shows the obtained low temperature characteristic values.
• Low temperature characteristics C / D (8)
• a graph was created with the applied current value (A) as the horizontal axis and the voltage value (V) as the vertical axis, and the slope value of the straight line connecting the plot points was calculated at each charge / discharge time.
• the gradient values were taken as internal DC resistance values (DC-IR) during charging and discharging, respectively.
• Electrolytic solution of EC: DEC 3: 7 (volume ratio) containing DC-IR of “E” and LiPF 6 of 1 mol / L of the secondary battery cell produced using the above gel electrolyte forming composition
• the DC-IR characteristic of the secondary battery cell produced using the battery is “F”
• the DC-IR characteristic represented by the following formula (9) is 2.5 or less. be able to.
• DC-IR characteristics E / F (9)
• Table 3 shows the obtained DC-IR characteristic values.
• DOD indicates the ratio of the discharge capacity to the charge capacity.
• charge to 50% DOD indicates that only 50% of the capacity is charged when the total capacity is 100%.
• the discharge rate characteristic represented by the following formula (10) is 0.7 or more when the discharge capacity maintenance ratio at the 50th cycle of the secondary battery cell manufactured using the electrolyte solution of (R) is “H” If it is, it can be evaluated that it is favorable.
• Example 28 Comparative Examples 4 to 6
• 6 parts by mass of the polymer P1 obtained above as a component (A) and 0.2 parts by mass of vinylene carbonate (VC) as a component (B) were weighed out, and no bubbles were mixed therein.
• a gel electrolyte forming agent was prepared by sufficiently stirring, mixing and homogenizing under reduced pressure.
• Each evaluation test was performed in the same manner as in Example 1 except that this gel electrolyte forming agent was used.
• Examples 29 to 60 and Comparative Examples 4 to 6 were the same as Example 1 except that gel electrolyte forming agents were prepared in the same manner as in Example 28 so as to have the compositions shown in Tables 5 to 7. Each evaluation test was conducted.
• Example 61 6 parts by mass of the polymer P1 obtained above as component (A) and 0.035 of 2,6-di-t-butyl-4-methylphenol (BHT) as component (C) were used.
• a gel electrolyte forming agent was prepared by weighing out a mass part and thoroughly agitating, mixing, and homogenizing the mixture under reduced pressure so that bubbles do not enter. Each evaluation test was performed in the same manner as in Example 1 except that this gel electrolyte forming agent was used.
• Examples 62 to 83 and Comparative Examples 7 to 8 were the same as Example 1 except that gel electrolyte forming agents were prepared in the same manner as in Example 61 so that the compositions shown in Tables 8 to 10 were obtained. Each evaluation test was conducted.
• EC / DEC Mixed solvent of ethylene carbonate and diethyl carbonate in a volume ratio of 3: 7
• GBL ⁇ -butyrolactone
• DG diglyme (diethylene glycol dimethyl ether)
• DEC Diethyl carbonate
• MEK Methyl ethyl ketone
• PC Propylene carbonate
• CEL 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate (manufactured by Daicel Chemical Industries, Ltd., product name “Celoxide 2021P”)
• EGDG ethylene glycol diglycidyl ether
• DOX 3-ethyl-3 ⁇ [(3-ethyloxetane-3-yl) methoxy] methyl ⁇ oxetane
• OXAL 3-ethyl-3-hydroxymethyloxetane
• the present invention is not limited to the above embodiment, and various modifications can be made.
• the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects).
• the present invention also includes a configuration in which a non-essential part of the configuration described in the above embodiment is replaced with another configuration.
• the present invention includes a configuration that achieves the same effect as the configuration described in the above embodiment or a configuration that can achieve the same object.
• the present invention includes a configuration in which a known technique is added to the configuration described in the above embodiment.

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