Electrochemical device, composition, electrode mixture, electrode, and secondary battery

Abstract

The present invention provides: an electrochemical device having an excellent initial capacity and capacity retention rate; a composition capable of improving the initial capacity and capacity retention rate of an electrochemical device; an electrode mixture; an electrode; and a secondary battery. The electrochemical device includes an electrode active material and a lithium supplement in a positive electrode and / or a negative electrode, and includes a filament-forming resin in the positive electrode and / or the negative electrode.

Description

Electrochemical device, composition, electrode mixture, electrode, and secondary battery

[0001] The present disclosure relates to an electrochemical device, a composition, an electrode mixture, an electrode, and a secondary battery.

[0002] Secondary batteries such as lithium-ion secondary batteries are used in small, portable electrical and electronic devices such as notebook computers, mobile phones, smartphones, tablet computers, and ultrabooks because of their high voltage, high energy density, low self-discharge, low memory effect, and the ability to be ultra-lightweight, and are also being put into practical use as a wide range of power sources, including on-board power sources for driving automobiles and large-scale stationary power sources. Demand is now being placed on secondary batteries to achieve even higher energy densities, and further improvements in their battery characteristics are being sought.

[0003] In Patent Document 1 and Non-Patent Document 1, Li ２ NiO ２ , Li ５ FeO ４ It is described that a lithium compound such as the above is added to the positive electrode of a battery.

[0004] Special Publication No. 2023-534756

[0005] Linghong Zhang, 4 others, “Mitigating the initial capacity loss and improving the cycling stability of silicon monoxide using Li5FeO4”, Journal of Power Sources, Volume 400, 1 October 2018, pp. 549-555

[0006] An object of the present disclosure is to provide an electrochemical device having excellent initial capacity and capacity retention rate, as well as a composition, electrode mixture, electrode, and secondary battery that can improve the initial capacity and capacity retention rate of an electrochemical device.

[0007] The present disclosure (1) is an electrochemical device comprising an electrode active material and a lithium supplement in a positive electrode and / or a negative electrode, and comprising a fibrillating resin in the positive electrode and / or a negative electrode.

[0008] In the present disclosure (2), the lithium supplement is Li ５ FeO ４ , Li ５ AlO and Li ２ NiO ２ The electrochemical device according to the present disclosure (1) is at least one selected from the group consisting of:

[0009] The present disclosure (3) provides that the lithium supplement is Li ５ FeO ４ and Li ２ NiO ２ The electrochemical device according to the present disclosure (1) or (2) is at least one selected from the group consisting of:

[0010] The present disclosure (4) is the electrochemical device according to any one of the present disclosures (1) to (3), in which a coating layer of the lithium replenisher is formed on the surface of the electrode active material.

[0011] The present disclosure (5) is the electrochemical device according to any one of the present disclosures (1) to (4), wherein the negative electrode contains at least one selected from the group consisting of graphite and Si.

[0012] The present disclosure (6) is the electrochemical device according to any one of the present disclosures (1) to (5), wherein the positive electrode and / or the negative electrode containing the fibrillating resin is produced by a dry process.

[0013] The present disclosure (7) is the electrochemical device according to any one of the present disclosures (1) to (6), wherein the fibrillating resin is a tetrafluoroethylene-based polymer.

[0014] The present disclosure (8) is the electrochemical device according to any one of the present disclosures (1) to (7), wherein the fibrillating resin is polytetrafluoroethylene.

[0015] The present disclosure (9) is the electrochemical device according to any one of the present disclosures (1) to (8), wherein the fibrillating resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene consisting only of a tetrafluoroethylene unit and a polymerization unit based on hexafluoropropylene.

[0016] The present disclosure (10) is the electrochemical device according to any one of the present disclosures (1) to (9), wherein the amount of the fibrillating resin relative to the electrode mixture in the positive electrode and / or negative electrode is 0.3 to 10 mass%.

[0017] The present disclosure (11) is the electrochemical device according to any one of the present disclosures (1) to (10), wherein the positive electrode contains the lithium supplement and a fibrillating resin.

[0018] The present disclosure (12) is an electrochemical device according to any one of the present disclosures (1) to (11), which is an electrolyte secondary battery or an electrolyte capacitor.

[0019] The present disclosure (13) is an electrochemical device according to any one of the present disclosures (1) to (12), which is a lithium ion secondary battery.

[0020] The present disclosure (14) is a composition comprising a lithium supplement and a fibrillating resin.

[0021] The present disclosure (15) is the composition according to the present disclosure (14), wherein the fibrillating resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene consisting only of a tetrafluoroethylene unit and a polymerization unit based on hexafluoropropylene.

[0022] The present disclosure (16) relates to a method for producing a lithium replenisher, comprising: ５ FeO ４ and Li ２ NiO ２ The composition according to the present disclosure (14) or (15) is at least one selected from the group consisting of:

[0023] The present disclosure (17) is the composition according to any one of the present disclosures (14) to (16), wherein the total amount of the lithium supplement and the fibrillating resin relative to the composition is 95 mass% or more.

[0024] The present disclosure (18) is a composition according to any one of the present disclosures (14) to (17), in which the mass ratio of the fibrillating resin to the Li replenisher (fibrillating resin / Li replenisher) is 50 / 50 or more and 70 / 30 or less.

[0025] The present disclosure (19) is the composition according to any one of the present disclosures (14) to (18), in which the liquid content is 10% by mass or less.

[0026] The present disclosure (20) is a composition according to any one of the present disclosures (14) to (19) which is a powder.

[0027] The present disclosure (21) is the composition according to any one of the present disclosures (14) to (20), which is a binder for electrochemical devices.

[0028] The present disclosure (22) is the composition according to any one of the present disclosures (14) to (21), which is a binder for a lithium ion secondary battery.

[0029] The present disclosure (23) is an electrode mixture comprising the composition according to any one of the present disclosures (14) to (22) and an electrode active material.

[0030] The present disclosure (24) is the electrode mixture according to the present disclosure (23) in the form of a sheet.

[0031] The present disclosure (25) is an electrode comprising the composition according to any one of the present disclosures (14) to (22), an electrode active material, and a current collector.

[0032] The present disclosure (26) is a secondary battery including the electrode mixture according to the present disclosure (23) and a current collector.

[0033] According to the present disclosure, it is possible to provide an electrochemical device having excellent initial capacity and capacity retention rate, as well as a composition, an electrode mixture, an electrode, and a secondary battery that can improve the initial capacity and capacity retention rate of an electrochemical device.

[0034] In the present disclosure, the term "organic group" refers to a group containing one or more carbon atoms or a group formed by removing one hydrogen atom from an organic compound. The organic group is preferably an alkyl group which may have one or more substituents.

[0035] The present disclosure will be specifically described below.

[0036] The present disclosure provides an electrochemical device comprising an electrode active material and a lithium (Li) replenisher in the positive and / or negative electrodes, and comprising a fibrillating resin in the positive and / or negative electrodes.

[0037] The electrochemical device of the present disclosure has the above-described configuration, resulting in excellent initial capacity and capacity retention. When a fibrillating resin such as a TFE-based polymer is used as a binder, the fibrillating resin may react with Li in the system, resulting in the loss of Li necessary for the electrochemical device reaction. Furthermore, when a Si-based active material such as Si or SiO is used in the negative electrode, Li in the system may be irreversibly consumed by reaction with the active material, particularly during the initial charge. The Li replenisher is a compound that can irreversibly release Li and can replenish the lost Li, thereby improving the initial capacity and capacity retention of the electrochemical device.

[0038] In the electrochemical device of the present disclosure, the Li replenisher may be contained in only one of the positive electrode and the negative electrode, or in both, but is preferably contained in the positive electrode in order to further improve the initial capacity and capacity retention rate. The fibrillating resin may be contained in only one of the positive electrode and the negative electrode, or in both. Furthermore, the Li replenisher and the fibrillating resin may be contained in the same electrode or in separate electrodes. In particular, it is preferable that at least the positive electrode contains the Li replenisher and the fibrillating resin.

[0039] The Li replenisher may be a Li-containing compound that undergoes an oxidation reaction and does not substantially undergo a reduction reaction in the charge / discharge potential range of the positive electrode active material. "Occurs an oxidation reaction in the charge / discharge potential range of the positive electrode active material" means that an oxidation reaction can occur in the charge / discharge potential range of the positive electrode active material to release Li ions and electrons (including decomposition by an oxidation reaction and release of Li ions) in the charge / discharge potential range of the positive electrode active material. Furthermore, "does not substantially undergo a reduction reaction in the charge / discharge potential range of the positive electrode active material" means that, under reaction conditions common to those skilled in the art, a reduction reaction to receive Li ions and electrons or to generate them via a reduction reaction is impossible or substantially impossible in the charge / discharge potential range of the positive electrode active material. "Reaction conditions common to those skilled in the art" refer to, for example, the conditions under which a lithium secondary battery is discharged. Furthermore, "substantially unable to undergo a reduction reaction to receive Li ions and electrons or to generate Li via a reduction reaction" means that, of the Li replenishers oxidized by charging the battery, 80% or more by volume of the Li replenishers cannot undergo a reduction reaction to receive Li ions and electrons or to generate Li via a reduction reaction. "Charge-discharge potential range of the positive electrode active material" refers to the potential range in which oxidation and reduction reactions of the positive electrode active material contained in the positive electrode can occur. The Li replenisher can supply sufficient Li to the negative electrode during the initial charge, thereby replenishing Li consumed at the negative electrode in subsequent cycles, thereby improving the initial capacity and capacity retention rate of the electrochemical device.

[0040] The Li replenisher may be Li ２ O ２ Lithium oxides such as Li ３ Lithium nitrides such as N; Li １＋ｘ (Ti １－ｙ Fe ｙ ) １－ｘ O ２ (0<x≦0.25, 0.4<y≦0.9), Li ２－ｘ Ti １－ｚ Fe ｚ O ３－ｙ (0≦x<2, 0≦y≦1, 0.05≦z≦0.95), Li ５ FeO ４Iron-based lithium oxides such as Li ５ AlO; Li ２ NiO ２ These may be used alone or in combination of two or more. ５ AlO and Li ２ NiO ２ At least one selected from the group consisting of Li ５ FeO ４ , Li ５ AlO and Li ２ NiO ２ At least one selected from the group consisting of Li ５ FeO ４ and Li ２ NiO ２ More preferably, at least one selected from the group consisting of Li ５ FeO ４ is even more preferred.

[0041] The content of the Li replenisher is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, even more preferably 2.0% by mass or more, and is preferably 10% by mass or less, more preferably 8.0% by mass or less, even more preferably 7.0% by mass or less, even more preferably 5.0% by mass or less, and even more preferably 4.0% by mass or less, relative to the electrode mixture in the electrode (positive electrode and / or negative electrode) containing the Li replenisher, in order to further improve the initial capacity and capacity retention rate of the electrochemical device.

[0042] In the electrochemical device of the present disclosure, the fibrillating resin may function as a binder that holds the electrode active material and the like.

[0043] The fibrillating resin is a resin that easily fibrillates when shear stress is applied. The higher the molecular weight, the easier it is to fibrillate. The molecular weight of the fibrillating resin is, for example, 500,000 or more, preferably 1,000,000 or more, more preferably 5,000,000 or more, even more preferably 10,000,000 or more, even more preferably 20,000,000 or more, and may be 200,000,000 or less. The molecular weight may be a number average molecular weight (Mn) and can be calculated by the following formula: SSG = -0.0579 log Mn + 2.6113, where SSG is the standard specific gravity of the polymer, and is measured by the water displacement method according to ASTM D 792 using a sample molded in accordance with ASTM D 4895 89.

[0044] The fibrillating resin is preferably one polymerized using a fluorine-containing surfactant, more preferably one polymerized using a hydrocarbon-based surfactant, in that it can further improve the initial capacity and capacity retention rate of the electrochemical device and further improve powder fluidity.

[0045] The fibrillating resin preferably has a thermal instability index (TII) of 10 or more. A fibrillating resin having a TII of 10 or more can be obtained by using a hydrocarbon surfactant. In terms of further improving the initial capacity and capacity retention rate of an electrochemical device and further improving powder flowability, the TII is more preferably 15 or more, even more preferably 20 or more, and even more preferably 25 or more, and is preferably 80 or less, more preferably 50 or less. The TII is measured in accordance with ASTM D 4895-89.

[0046] The fibrillating resin may have a 0.1% mass loss temperature of 400°C or less. A fibrillating resin having a 0.1% mass loss temperature of 400°C or less can be obtained by using a hydrocarbon surfactant. The 0.1% mass loss temperature is a value measured by the following method. Approximately 10 mg of fibrillating resin that has not been heated to temperatures above 300°C is precisely weighed, placed in a dedicated aluminum pan, and measured using a TG / DTA (thermogravimetric / differential thermal analyzer). The 0.1% mass loss temperature is determined as the temperature at which a 0.1 mass% weight loss occurs when the aluminum pan is heated in an air atmosphere over a temperature range from 25°C to 600°C at a rate of 10°C / min.

[0047] The fibrillating resin may have a 1.0% mass loss temperature of 492°C or lower. A fibrillating resin having a 1.0% mass loss temperature of 492°C or lower can be obtained by using a hydrocarbon surfactant. The 1.0% mass loss temperature is a value measured by the following method. Approximately 10 mg of fibrillating resin that has not been heated to temperatures of 300°C or higher is precisely weighed, placed in a dedicated aluminum pan, and measured using a TG / DTA (thermogravimetric / differential thermal analyzer). The 1.0% mass loss temperature is determined as the temperature at which a 1.0 mass% weight loss occurs when the aluminum pan is heated in an air atmosphere over a temperature range of 25°C to 600°C at a rate of 10°C / min.

[0048] The fibrillating resin preferably has an endothermic peak temperature of more than 330°C, more preferably 333°C or higher, even more preferably 335°C or higher, even more preferably 337°C or higher, particularly preferably 340°C or higher, and preferably 350°C or lower, more preferably 346°C or lower, in order to form a composite sheet with even greater strength. The endothermic peak temperature is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry (DSC) at a heating rate of 10°C / min on a fibrillating polymer that has not been heated to a temperature of 300°C or higher. When there are two or more minimum points in one melting peak, each of these is taken as the endothermic peak temperature.

[0049] Examples of the fibrillating resin include tetrafluoroethylene (TFE)-based polymers, polyethylene, polyester, liquid crystal polymers (LCP), acrylic resins, etc. As the fibrillating resin, TFE-based polymers, polyethylene, and polyester are preferred, and TFE-based polymers are more preferred.

[0050] The TFE-based polymer may be a TFE homopolymer, or a TFE copolymer containing TFE-based polymerization units (TFE units) and TFE-based polymerization units (modified monomer units) copolymerizable with modified monomers. The TFE-based polymer may be polytetrafluoroethylene (PTFE). The PTFE includes TFE homopolymers and modified PTFE containing 99.0% by mass or more of TFE units and 1.0% by mass or less of modified monomer units. The TFE-based polymer is preferably PTFE, and more preferably modified PTFE, in that it can further improve the initial capacity and capacity retention rate of electrochemical devices and further improve powder flowability. In the present disclosure, the TFE copolymer refers to one in which the content of modified monomer units relative to the total polymerization units is 10% by mass or less, and the TFE homopolymer refers to one in which the content of modified monomer units relative to the total polymerization units is less than 0.0001% by mass.

[0051] The content of the modified monomer unit is preferably in the range of 0.0001 to 10 mass% relative to the total polymerized units, from the viewpoint of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving powder fluidity. The lower limit of the content of the modified monomer unit is more preferably 0.001 mass%, even more preferably 0.010 mass%, even more preferably 0.015 mass%, and particularly preferably 0.020 mass%. The upper limit of the content of the modified monomer unit is preferably 5.0 mass%, more preferably 3.0 mass%, even more preferably 1.0 mass%, even more preferably 0.80 mass%, even more preferably 0.60 mass%, even more preferably 0.50 mass%, even more preferably 0.40 mass%, even more preferably 0.30 mass%, and particularly preferably 0.20 mass%. In this specification, the modified monomer unit refers to a portion of the molecular structure of the TFE-based polymer that is derived from the modified monomer.

[0052] The content of each of the above-mentioned polymerized units can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and X-ray fluorescence analysis depending on the type of monomer.

[0053] As the above-mentioned modified monomer, as long as it can be copolymerized with TFE, there is no particular limitation, for example, can be listed perfluoroolefin such as hexafluoropropylene (HFP); trifluoroethylene, vinylidene fluoride (VDF) etc. hydrogen-containing fluoroolefin; perhaloolefin such as chlorotrifluoroethylene (CTFE); perfluorovinyl ether; perfluoroallyl ether; (perfluoroalkyl) ethylene, ethylene, the monomer with polar group etc. In addition, the modified monomer used can be one kind or multiple kinds.

[0054] The perfluorovinyl ether is not particularly limited, and examples thereof include perfluorovinyl ethers represented by the following general formula (A): CF ２ =CF-ORf １ (A) (wherein, Rf １represents a perfluoroorganic group. ) and perfluorounsaturated compounds represented by the following formula: In this specification, the "perfluoroorganic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are substituted with fluorine atoms. The perfluoroorganic group may have an ether oxygen.

[0055] The perfluorovinyl ether is, for example, perfluoro(alkyl vinyl ether) [PAVE], preferably, Rf １ is a perfluoroalkyl group having 1 to 10 carbon atoms. The number of carbon atoms in the perfluoroalkyl group is preferably 1 to 5.

[0056] Examples of the perfluoroalkyl group in the PAVE include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group.

[0057] The perfluorovinyl ether further includes a compound represented by the general formula (A) below, wherein Rf １ is a perfluoro(alkoxyalkyl) group having 4 to 9 carbon atoms, Rf １ is of the following formula:

[0058]

[0059] (wherein m represents 0 or an integer of 1 to 4), Rf １ is of the following formula:

[0060]

[0061] (wherein n represents an integer of 1 to 4).

[0062] The (perfluoroalkyl)ethylene [PFAE] is not particularly limited, and examples thereof include (perfluorobutyl)ethylene [PFBE] and (perfluorohexyl)ethylene.

[0063] Examples of perfluoroallyl ethers include those represented by the general formula (B): CF ２ =CF-CF ２-ORf ２ (B) (wherein, Rf ２ represents a perfluoroorganic group.

[0064] The above Rf ２ is preferably a perfluoroalkyl group having 1 to 10 carbon atoms or a perfluoroalkoxyalkyl group having 1 to 10 carbon atoms. ２ =CF-CF ２ -O-CF ３ , C.F. ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ At least one selected from the group consisting of CF ２ =CF-CF ２ -O-C ２ F ５ , C.F. ２ =CF-CF ２ -O-C ３ F ７ , and CF ２ =CF-CF ２ -O-C ４ F ９ More preferably, at least one selected from the group consisting of CF ２ =CF-CF ２ -O-CF ２ CF ２ CF ３ is more preferred.

[0065] The modified monomer is represented by the following general formula (i): CX １ X ２ =CX ３ X ４ (i) (wherein, X １ ~X ３ are each independently H or F. ４is F, Cl, Rf or O-Rf, and Rf is a perfluoroorganic group.

[0066] Rf in general formula (i) is preferably a perfluoroalkyl group having 1 to 10 carbon atoms, more preferably a perfluoroalkyl group having 1 to 5 carbon atoms, and even more preferably a perfluoroalkyl group having 1 to 4 carbon atoms.

[0067] The polar group-containing monomer may be a fluorine-free monomer or a fluorine-containing monomer.

[0068] Examples of the fluorine-free monomer include hydroxyl group-containing fluorine-free monomers such as hydroxyalkyl vinyl ethers, such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyisobutyl vinyl ether, and hydroxycyclohexyl vinyl ether; carboxyl group-containing fluorine-free monomers, such as acrylic acid, methacrylic acid, itaconic acid, succinic acid, fumaric acid, crotonic acid, maleic acid, citraconic acid, undecylenic acid, and acetylenedicarboxylic acid; itaconic anhydride (hereinafter also referred to as "IAH"), citraconic anhydride (hereinafter also referred to as "CAH"), 5-norbornene-2, Examples of suitable monomers include 3-dicarboxylic acid anhydride (hereinafter also referred to as "NAH"), succinic anhydride, fumaric anhydride, maleic anhydride, and other fluorine-containing monomers having an acid anhydride residue; fluorine-containing monomers having a sulfo group such as vinyl sulfonic acid; fluorine-containing monomers having an epoxy group (glycidyl group) such as glycidyl vinyl ether and glycidyl allyl ether; fluorine-containing monomers having an amino group such as aminoalkyl vinyl ether and aminoalkyl allyl ether; fluorine-containing monomers having an amide group such as (meth)acrylamide and methylolacrylamide; and fluorine-containing monomers having a nitrile group such as acrylonitrile and methacrylonitrile. Among these, preferred are fluorine-containing monomers having a carboxy group and fluorine-containing monomers having an acid anhydride residue, more preferred are fluorine-containing monomers having an acid anhydride residue, and even more preferred are cyclic fluorine-containing monomers having an acid anhydride residue.

[0069] The polar group-containing monomer preferably includes a modified monomer having a functional group capable of reacting by radical polymerization and a hydrophilic group (hereinafter referred to as "modified monomer (A)").

[0070] The hydrophilic group in the modified monomer (A) is, for example, —NH ２ , -PO ３ M, -OPO ３ M, -SO ３ M, -OSO ３ M, -COOM (in each formula, M is H, a metal atom, NR ７ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, R ７ are H or organic groups and may be the same or different. Any two of them may be bonded to each other to form a ring.) Among the above hydrophilic groups, -SO ３ M or -COOM is preferred. ７ As the group, H or C １－１０ is preferably an organic group represented by the formula: １－４ More preferred are organic groups represented by the formula: １－４ The metal atom is preferably a monovalent or divalent metal atom, such as an alkali metal (Group 1) or an alkaline earth metal (Group 2), and more preferably Na, K, or Li.

[0071] Examples of the "functional group capable of reacting by radical polymerization" in the modifying monomer (A) include groups having an ethylenically unsaturated bond, such as a vinyl group and an allyl group. The group having an ethylenically unsaturated bond is a group represented by the following formula: CX ｅ X ｇ =CX ｆ R- (wherein, X ｅ , X ｆ and X ｇ are each independently F, Cl, H, or CF ３ , C.F. ２ H, C.F.H. ２ , or CH ３ and R is a linking group. The linking group of R can be represented by the formula: ａPreferably, the linking group is -CH=CH ２ , -CF=CH ２、 -CH=CF ２、 -CF = CF ２ , -CH ２ -CH=CH ２ , -CF ２ -CF=CH ２ , -CF ２ -CF = CF ２ , -(C=O)-CH=CH ２ , -(C=O)-CF=CH ２ , -(C=O)-CH=CF ２ , -(C=O)-CF=CF ２ , -(C=O)-C(CH ３ ) = CH ２ , -(C=O)-C(CF ３ ) = CH ２ , -(C=O)-C(CH ３ ) = CF ２ , -(C=O)-C(CF ３ ) = CF ２ , —O—CH ２ -CH=CH ２ , —O—CF ２ -CF=CH ２ , —O—CH ２ -CH=CF ２ , —O—CF ２ -CF = CF ２ Examples of groups having an unsaturated bond include the following.

[0072] The modified monomer (A) has a functional group capable of reacting by radical polymerization, so when used in polymerization, it is assumed that it will react with the fluorine-containing monomer at the initial stage of the polymerization reaction, and form particles having hydrophilic groups derived from the modified monomer (A) and having high stability.Therefore, it is thought that when polymerization is carried out in the presence of the modified monomer (A), the number of particles will increase.

[0073] The modifying monomer (A) may be used alone or in combination of two or more.

[0074] As the modifying monomer (A), a compound having an unsaturated bond can be used.

[0075] The modifying monomer (A) is preferably at least one selected from the group consisting of compounds represented by the following formulas (4a) to (4e): CF ２ =CF-(CF ２ ) ｎ１ -Y ３ (4a) (wherein n1 represents an integer of 1 to 10, and Y ３ is -SO ３ M １ or -COOM １ represents M １ , H, NH ４ or an alkali metal.) CF ２ =CF-(CF ２ C (CF ３ ) F) ｎ２ -Y ３ (4b) (wherein n2 represents an integer of 1 to 5, and Y ３ is the same as the definition above.) CF ２ =CF-O-(CFX １ ) ｎ３ -Y ３ (4c) (wherein, X １ is F or CF ３ n3 represents an integer of 1 to 10; Y ３ is the same as the definition above.) CF ２ =CF-O-(CF ２ CFX １ O) ｎ４ -CF ２ CF ２ -Y ３ (4d) (wherein n4 represents an integer of 1 to 10, and Y ３ and X １ is the same as the above definition.) CX ２ ２ =CFCF ２ -O-(CF(CF ３ )CF ２ O) ｎ５ -CF (CF ３ )-Y ３ (4e) (In the formula, each ２ are the same and represent F or H. n5 represents 0 or an integer of 1 to 10, Y ３ is the same as defined above.) Examples of the alkali metal include Na and K.

[0076] In the formula (4a), n1 is preferably an integer of 5 or less, and more preferably an integer of 2 or less. ３ is advantageous in that it has a suitable water solubility and surface activity. １ Preferably, M １ is preferred because it is unlikely to remain as an impurity and the heat resistance of the resulting molded article is improved. ４ It is preferable that:

[0077] Examples of the perfluorovinyl alkyl compound represented by the formula (4a) include CF ２ =CFCF ２ COOM １ (In the formula, M １ is the same as the definition above.

[0078] In the formula (4b), n2 is preferably an integer of 3 or less from the viewpoint of emulsifying ability, and Y ３ is preferred in that it provides adequate water solubility and surface activity. １ Preferably, M １ is preferred because it is unlikely to remain as an impurity and the heat resistance of the resulting molded article is improved. ４ It is preferable that:

[0079] In the formula (4c), n3 is preferably an integer of 5 or less in terms of water solubility, and Y ３ is preferred in that it provides adequate water solubility and surface activity. １ It is preferable that the above M １ is H or NH in that dispersion stability is improved. ４ It is preferable that:

[0080] In the formula (4d), the X １ In terms of surfactant activity, -CF ３ In terms of water solubility, n4 is preferably an integer of 5 or less, and Y ３ COOM has the advantage of providing adequate water solubility and surface activity. １ It is preferable that the above M １ is H or NH ４It is preferable that:

[0081] Examples of the perfluorovinyl ether compound represented by the formula (4d) include CF ２ = CFOCF ２ CF (CF ３ ) OCF ２ CF ２ COOM １ (In the formula, M １ , H, NH ４ or an alkali metal.

[0082] In the formula (4e), n5 is preferably 0 or an integer of 1 to 5, more preferably 0, 1 or 2, and even more preferably 0 or 1, in terms of emulsifying ability. ３ COOM has the advantage of providing adequate water solubility and surface activity. １ It is preferable that the above M １ is preferred in that it is unlikely to remain as an impurity and the heat resistance of the resulting molded article is improved. ４ It is preferable that:

[0083] Examples of the perfluorovinyl alkyl compound represented by the formula (4e) include CH ２ =CFCF ２ OCF (CF ３ ) COOM １ , C.H. ２ =CFCF ２ OCF (CF ３ )CF ２ OCF (CF ３ ) COOM1 (in the formula, M １ is the same as the definition above.

[0084] As the modified monomer, from the viewpoint of further improving the initial capacity and capacity retention rate of the electrochemical device and further improving powder fluidity, at least one selected from the group consisting of HFP, PAVE, PFAE, and a monomer having a polar group is preferred, at least one selected from the group consisting of HFP, perfluoro(methyl vinyl ether) [PMVE], perfluoro(propyl vinyl ether) [PPVE], PFBE, a non-fluorinated monomer having an acid anhydride residue, and the modified monomer (A) is more preferred, at least one selected from the group consisting of HFP, PMVE, PPVE, a cyclic non-fluorinated monomer having an acid anhydride residue, and a compound represented by general formula (4e) is even more preferred, at least one selected from the group consisting of HFP, PMVE, and PPVE is even more preferred, and HFP is even more preferred.

[0085] The TFE-based polymer is preferably at least one selected from the group consisting of a TFE homopolymer and a modified PTFE containing TFE units and polymerization units based on HFP, and more preferably at least one selected from the group consisting of a TFE homopolymer and a modified PTFE consisting only of TFE units and polymerization units based on HFP.

[0086] The above-mentioned TFE polymer may have a core-shell structure.As the TFE polymer having a core-shell structure, for example, there can be mentioned the TFE copolymer, in which the core of the TFE polymer of high molecular weight is contained in the particle, and the shell of the TFE polymer or TFE copolymer of lower molecular weight is contained in the particle.In addition, there can be mentioned the modified PTFE, in which the core of the PTFE of high molecular weight is contained in the particle, and the shell of the PTFE or modified PTFE of lower molecular weight is contained in the particle.As such modified PTFE, there can be mentioned the PTFE described in JP-T-2005-527652.

[0087] Preferably, above-mentioned TFE polymer is non-melt processable.In this specification, non-melt processable means that melt flow rate (MFR) is less than 0.25g / 10min, preferably less than 0.10g / 10min, more preferably 0.05g / 10min or less, even more preferably 0.01g / 10min or less.Above-mentioned MFR is the value (g / 10min) of the polymer mass that flows out per 10 minutes from a nozzle with an inner diameter of 2.095mm and a length of 8mm according to ASTM D1238, at 372 ℃ and a load of 5kg, using a melt indexer.

[0088] In terms of being able to further improve the initial capacity and capacity retention rate of an electrochemical device and further improving powder fluidity, the TII of the TFE-based polymer is preferably 10 or more, more preferably 15 or more, even more preferably 20 or more, and even more preferably 25 or more, and is preferably 80 or less, and more preferably 50 or less. A TFE-based polymer having a TII of 10 or more can be obtained by using a hydrocarbon-based surfactant.

[0089] The TFE-based polymer can form a composite sheet having better strength, and therefore the standard specific gravity (SSG) is preferably 2.280 or less, more preferably 2.250 or less, even more preferably 2.220 or less, even more preferably 2.200 or less, even more preferably 2.190 or less, particularly preferably 2.180 or less, and particularly preferably 2.170 or less.The SSG is also preferably 2.130 or more, more preferably 2.140 or more, and even more preferably 2.150 or more.The SSG is measured by the water displacement method according to ASTM D 792 using a sample molded according to ASTM D 4895 89.

[0090] The content of the fibrillating resin is preferably 0.3 mass% or more, more preferably 0.5 mass% or more, even more preferably 1.0 mass% or more, and even more preferably 1.5 mass% or more of the electrode mixture in the electrode (positive electrode and / or negative electrode) containing the fibrillating resin, in order to further improve the initial capacity and capacity retention rate of the electrochemical device, and is preferably 10 mass% or less, more preferably 8.0 mass% or less, even more preferably 7.0 mass% or less, even more preferably 5.0 mass% or less, and even more preferably 3.0 mass% or less.

[0091] The electrodes (positive electrode and / or negative electrode) included in the electrochemical device of the present disclosure contain an electrode active material.

[0092] Examples of the electrode active material include a positive electrode active material and a negative electrode active material.

[0093] The positive electrode active material is not particularly limited as long as it can electrochemically absorb and release alkali metal ions, but for example, a material containing an alkali metal and at least one transition metal is preferred. Specific examples include alkali metal-containing transition metal composite oxides and alkali metal-containing transition metal phosphate compounds. Of these, alkali metal-containing transition metal composite oxides that generate high voltage are particularly preferred as the positive electrode active material. Examples of the alkali metal ions include lithium ions, sodium ions, and potassium ions. In a preferred embodiment, the alkali metal ions may be lithium ions. That is, in this embodiment, the alkali metal ion secondary battery is a lithium ion secondary battery.

[0094] Examples of the alkali metal-containing transition metal composite oxide include those represented by the formula: M ａ Mn ２－ｂ M １ ｂ O ４ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0.9≦a; 0≦b≦1.5; M １is at least one metal selected from the group consisting of Fe, Co, Ni, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), alkali metal-manganese spinel composite oxides (such as lithium-manganese spinel composite oxides) represented by the formula: MNi １－ｃ M ２ ｃ O ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦c≦0.5; M ２ is at least one metal selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge), or an alkali metal-nickel composite oxide (such as a lithium-nickel composite oxide) represented by the formula: MCo １－ｄ M ３ ｄ O ２ (Wherein, M is at least one metal selected from the group consisting of Li, Na, and K; 0≦d≦0.5; M ３ is at least one metal selected from the group consisting of Fe, Ni, Mn, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li.

[0095] Among these, MCoO is preferred because it can provide a secondary battery with high energy density and high output. ２ , M MnO ２ , MNiO ２ , M.M. ２ O ４ , MNi ０．８ Co ０．１５ Al ０．０５ O ２ , or MNi １／３ Co １／３ Mn １／３ O ２ and the like are preferred, and a compound represented by the following general formula (3) is preferred: MNiｈ Co ｉ Mn ｊ M ５ ｋ O ２ (3) (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ５ represents at least one selected from the group consisting of Fe, Cu, Zn, Al, Sn, Cr, V, Ti, Mg, Ca, Sr, B, Ga, In, Si, and Ge, and (h+i+j+k)=1.0, 0≦h≦1.0, 0≦i≦1.0, 0≦j≦1.5, 0≦k≦0.2.

[0096] Examples of the alkali metal-containing transition metal phosphate compound include those represented by the following general formula (4): ｅ M ４ ｆ (P.O. ４ ) ｇ (4) (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ４ represents at least one selected from the group consisting of V, Ti, Cr, Mn, Fe, Co, Ni, and Cu, and 0.5≦e≦3, 1≦f≦2, and 1≦g≦3. In the above, M is preferably one metal selected from the group consisting of Li, Na, and K, more preferably Li or Na, and even more preferably Li. That is, the alkali metal-containing transition metal phosphate compound is preferably a lithium-containing transition metal phosphate compound.

[0097] The transition metal of the lithium-containing transition metal phosphate compound is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu, or the like, and specific examples thereof include LiFePO ４ , Li ３ Fe ２ (P.O. ４ ) ３ , LiFeP ２ O ７ Iron phosphates such as LiCoPO ４and lithium transition metal phosphate compounds in which a part of the transition metal atoms constituting the main component of these compounds is substituted with other elements such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, etc. The lithium-containing transition metal phosphate compounds preferably have an olivine structure.

[0098] Other examples of the positive electrode active material include lithium-nickel composite oxides. The lithium-nickel composite oxides are represented by the following general formula (5): Li ｙ Ni １－ｘ M ｘ O ２ (5) (wherein x is 0.01≦x≦0.7, y is 0.9≦y≦2.0, and M is a metal atom (excluding Li and Ni)) is preferred.

[0099] Other positive electrode active materials include MFePO ４ , MNi ０．８ Co ０．２ O ２ , M １．２ Fe ０．４ Mn ０．４ O ２ , MNi ０．５ Mn １．５ O ２ , M.V. ３ O ６ , M ２ MnO ３ In particular, M ２ MnO ３ , MNi ０．５ Mn １．５ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K) are preferred in that the crystalline structure does not collapse even when the secondary battery is operated at a voltage exceeding 4.4 V or a voltage of 4.6 V or higher. Therefore, electrochemical devices such as secondary batteries using a cathode material containing the above-mentioned cathode active materials are preferred because the remaining capacity is less likely to decrease and the rate of increase in resistance is less likely to change even when stored at high temperatures, and the battery performance does not deteriorate even when operated at high voltages.

[0100] Other positive electrode active materials include M ２ MnO ３ and M.M. ６ O ２ (wherein M is at least one metal selected from the group consisting of Li, Na, and K, and M ６ Examples of the material include solid solution materials with transition metals such as Co, Ni, Mn, and Fe.

[0101] The solid solution material may be, for example, a material represented by the general formula M ｘ [Mn （１－ｙ） M ７ ｙ ]O ｚ In the formula, M is at least one metal selected from the group consisting of Li, Na, and K, and M ７ is composed of at least one metal element other than M and Mn, and contains, for example, one or more elements selected from the group consisting of Co, Ni, Fe, Ti, Mo, W, Cr, Zr and Sn. The values ​​of x, y and z in the formula are in the ranges of 1<x<2, 0≦y<1 and 1.5<z<3. Among them, Li １．２ Mn ０．５ Co ０．１４ Ni ０．１４ O ２ Li like ２ MnO ３ Based on LiNiO ２ and LiCoO ２ A manganese-containing solid solution material containing manganese is preferred in that it can provide an alkali metal ion secondary battery having a high energy density.

[0102] Furthermore, it is preferable to include lithium phosphate in the positive electrode active material, since this improves continuous charging characteristics. Although there is no limitation on the use of lithium phosphate, it is preferable to use a mixture of the positive electrode active material and lithium phosphate. The amount of lithium phosphate used, based on the total amount of the positive electrode active material and lithium phosphate, is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more, and is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 5% by mass or less.

[0103] Alternatively, a substance having a different composition may be attached to the surface of the positive electrode active material, such as an oxide, such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, or bismuth oxide; a sulfate, such as lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, or aluminum sulfate; a carbonate, such as lithium carbonate, calcium carbonate, or magnesium carbonate; or carbon.

[0104] These surface-attaching substances can be attached to the surface of the positive electrode active material by, for example, a method of dissolving or suspending the substance in a solvent, impregnating the positive electrode active material, and then drying, a method of dissolving or suspending a surface-attaching substance precursor in a solvent, impregnating the positive electrode active material, and then reacting the surface-attaching substance by heating, or a method of adding the substance to a positive electrode active material precursor and simultaneously baking the surface-attaching substance, etc. When carbon is attached, a method of mechanically attaching the carbonaceous material in the form of, for example, activated carbon, etc., after the surface-attaching substance is also available.

[0105] The amount of the surface-attached substance is, by mass relative to the positive electrode active material, preferably 0.1 ppm or more as the lower limit, more preferably 1 ppm or more, and even more preferably 10 ppm or more, and preferably 20% or less, more preferably 10% or less, and even more preferably 5% or less as the upper limit. The surface-attached substance can suppress the oxidation reaction of the electrolyte on the surface of the positive electrode active material and improve the battery life, but if the amount of attachment is too small, the effect will not be fully exerted, and if it is too large, the movement of lithium ions into and out of the positive electrode active material will be hindered, which may increase the resistance.

[0106] The shape of the particles of the positive electrode active material may be any of the conventional shapes such as block, polyhedron, sphere, oval sphere, plate, needle, column, etc. Furthermore, primary particles may aggregate to form secondary particles.

[0107] The tap density of the positive electrode active material is preferably 0.5 g / cm ３ More preferably, 0.8 g / cm ３ More preferably, 1.0 g / cm ３That is all. If the tap density of the positive electrode active material is below the above lower limit, the amount of dispersion medium required when forming the positive electrode active material layer increases, and the amounts of conductive material and binder required also increase, which may restrict the filling rate of the positive electrode active material in the positive electrode active material layer and restrict the battery capacity. By using a composite oxide powder with a high tap density, a high-density positive electrode active material layer can be formed. Generally, the higher the tap density, the more preferable it is, and there is no particular upper limit. However, if the tap density is too high, the diffusion of lithium ions in the positive electrode active material layer using the electrolyte as a medium becomes rate-limiting, and the load characteristics may be easily reduced. Therefore, the upper limit is preferably 4.0 g / cm. ３ or less, more preferably 3.7 g / cm ３ More preferably 3.5 g / cm or less ３ The tap density is the powder packing density (tap density) g / cm when 5 to 10 g of the positive electrode active material powder is placed in a 10 ml glass measuring cylinder and tapped 200 times with a stroke of about 20 mm. ３ is required.

[0108] The median diameter d50 of the particles of the positive electrode active material (the secondary particle diameter when primary particles are aggregated to form secondary particles) is preferably 0.3 μm or more, more preferably 0.5 μm or more, even more preferably 0.8 μm or more, and most preferably 1.0 μm or more, and is preferably 30 μm or less, more preferably 27 μm or less, even more preferably 25 μm or less, and most preferably 22 μm or less. If it is below the lower limit, a high tap density product may not be obtained, and if it exceeds the upper limit, it may take a long time for lithium to diffuse within the particles, resulting in problems such as a decrease in battery performance. Here, by mixing two or more types of the above positive electrode active materials having different median diameters d50, the filling ability during positive electrode production can be further improved.

[0109] The median diameter d50 is measured using a known laser diffraction / scattering particle size distribution analyzer. When using a HORIBA LA-920 particle size distribution analyzer, the measurement is performed using a 0.1% by mass aqueous solution of sodium hexametaphosphate as the dispersion medium, and after ultrasonic dispersion for 5 minutes, the measurement is performed with a refractive index set to 1.24.

[0110] When primary particles aggregate to form secondary particles, the average primary particle diameter of the positive electrode active material is preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.2 μm or more. The upper limit is preferably 5 μm or less, more preferably 4 μm or less, even more preferably 3 μm or less, and most preferably 2 μm or less. If the upper limit is exceeded, it is difficult to form spherical secondary particles, which may adversely affect powder packing and significantly reduce the specific surface area, thereby increasing the possibility of battery performance, such as output characteristics, being degraded. Conversely, if the lower limit is exceeded, problems such as poor charge / discharge reversibility may occur due to underdeveloped crystals. The average primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at 10,000x magnification, the longest intercepts of the horizontal line at the left and right boundaries of the primary particles are determined for any 50 primary particles, and the average is calculated.

[0111] The BET specific surface area of ​​the positive electrode active material is preferably 0.1 m ２ / g or more, more preferably 0.2m ２ / g or more, more preferably 0.3m ２ / g or more, and the upper limit is preferably 50m ２ / g or less, more preferably 40m ２ / g or less, more preferably 30m ２ / g or less. If the BET specific surface area is smaller than this range, battery performance is likely to decrease, while if it is larger, it is difficult to increase the tap density, which may lead to problems with processability when forming the positive electrode active material layer. The BET specific surface area is defined as a value measured by a nitrogen adsorption BET single-point method using a surface area meter (e.g., a fully automatic surface area measuring device manufactured by Ohkura Riken Co., Ltd.) after pre-drying a sample at 150°C for 30 minutes under a nitrogen flow, using a nitrogen-helium mixed gas accurately adjusted so that the relative pressure of nitrogen to atmospheric pressure is 0.3.

[0112] When the electrochemical device of the present disclosure is used as a large-scale lithium-ion secondary battery for hybrid vehicles or distributed power sources, high output is required, so it is preferable that the particles of the positive electrode active material are mainly secondary particles. The particles of the positive electrode active material preferably have an average secondary particle size of 40 μm or less and contain 0.5 to 7.0 volume % of fine particles having an average primary particle size of 1 μm or less. The inclusion of fine particles having an average primary particle size of 1 μm or less increases the contact area with the electrolyte, allowing for faster diffusion of lithium ions between the electrode mixture and the electrolyte, thereby improving the output performance of the battery.

[0113] For the production of a positive electrode, the positive electrode active material may be used alone, or two or more types of different compositions may be used in any combination or ratio. In this case, a preferred combination is LiCoO ２ and LiNi ０．３３ Co ０．３３ Mn ０．３３ O ２ combination with ternary systems such as LiCoO ２ and LiMn ２ O ４ Or a combination of this with a material in which a part of Mn is replaced with another transition metal, or LiFePO ４ and LiCoO ２ Alternatively, a combination of Co with other transition metals or the like may be used.

[0114] The content of the positive electrode active material is preferably 50 to 99.5% by mass of the positive electrode mixture, more preferably 80 to 99% by mass, in terms of high battery capacity. The content in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. The upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electrical capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient.

[0115] The negative electrode active material is not particularly limited, and examples thereof include carbonaceous materials such as lithium metal, artificial graphite, graphite carbon fiber, resin-baked carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-baked carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon; silicon-containing compounds such as silicon and silicon alloys; Li ４ Ti ５ O １２ Among these, those containing at least a carbonaceous material and silicon-containing compounds are particularly suitable.

[0116] The negative electrode active material used in the present disclosure preferably contains silicon as a constituent element, which allows the production of a high-capacity battery.

[0117] The silicon-containing material is preferably silicon particles, particles having a structure in which silicon fine particles are dispersed in a silicon-based compound, silicon oxide particles represented by the general formula SiOx (0.5≦x≦1.6), or a mixture thereof. By using these, a negative electrode mixture for a lithium ion secondary battery having higher initial charge / discharge efficiency, high capacity, and excellent cycle characteristics can be obtained.

[0118] In this disclosure, silicon oxide is a general term for amorphous silicon oxide, and silicon oxide before disproportionation is represented by the general formula SiOx (0.5≦x≦1.6). Preferably, x is 0.8≦x<1.6, and more preferably 0.8≦x<1.3. This silicon oxide can be obtained, for example, by heating a mixture of silicon dioxide and metallic silicon to produce silicon monoxide gas, which is then cooled and precipitated.

[0119] Particles having a structure in which silicon microparticles are dispersed in a silicon-based compound can be obtained, for example, by firing a mixture of silicon microparticles and a silicon-based compound, or by heat-treating pre-disproportionation silicon oxide particles represented by the general formula SiOx in an inert, non-oxidizing atmosphere such as argon at a temperature of 400°C or higher, preferably 800 to 1,100°C, to carry out a disproportionation reaction. Materials obtained by the latter method are particularly suitable because the silicon microcrystals are uniformly dispersed. The disproportionation reaction described above can reduce the size of silicon nanoparticles to 1 to 100 nm. The silicon oxide in particles having a structure in which silicon nanoparticles are dispersed in silicon oxide is preferably silicon dioxide. The dispersion of silicon nanoparticles (crystals) in amorphous silicon oxide can be confirmed using a transmission electron microscope.

[0120] The physical properties of the silicon-containing particles can be appropriately selected depending on the desired composite particles. For example, the average particle size is preferably 0.1 to 50 μm, with the lower limit being more preferably 0.2 μm or more, and even more preferably 0.5 μm or more. The upper limit is more preferably 30 μm or less, and even more preferably 20 μm or less. The average particle size is expressed as the weight-average particle size measured by particle size distribution measurement using a laser diffraction method.

[0121] BET specific surface area: 0.5 to 100 m ２ / g is preferred, and 1 to 20m ２ / g is more preferable. ２ If the adhesive strength is 100 m / g or more, there is no risk of the adhesive strength decreasing when processed into an electrode, and the battery characteristics decreasing. ２ / g or less, the proportion of silicon dioxide on the particle surface is large, and there is no risk of a decrease in battery capacity when used as a negative electrode material for a lithium ion secondary battery.

[0122] The silicon-containing particles are coated with carbon to impart conductivity, thereby improving battery performance. Methods for imparting conductivity include mixing the silicon-containing particles with conductive particles such as graphite, coating the surfaces of the silicon-containing particles with a carbon coating, and combining both methods. The carbon coating method is preferred, and chemical vapor deposition (CVD) is more preferred.

[0123] The negative electrode active material preferably contains at least one selected from the group consisting of graphite and Si, and may contain Si. When a Si-based active material such as Si is used in the negative electrode, Li in the system may be irreversibly consumed due to a reaction with the active material, particularly during initial charging, resulting in a decrease in the initial capacity and capacity retention of the electrochemical device. Since the positive electrode and / or negative electrode of the electrochemical device disclosed herein contain a Li replenisher, even when Si is used as the negative electrode active material, the consumed Li can be replenished, thereby improving the initial capacity and capacity retention of the electrochemical device.

[0124] In order to increase the capacity of the resulting electrode mixture, the content of the negative electrode active material is preferably 40% by mass or more, more preferably 50% by mass or more, and particularly preferably 60% by mass or more, of the electrode mixture, and the upper limit is preferably 99% by mass or less, more preferably 98% by mass or less.

[0125] The electrode active material in the electrode containing the Li replenisher preferably has a coating layer of the Li replenisher on its surface. This can further improve the initial capacity and capacity retention rate of the electrochemical device. The coating layer of the Li replenisher can be formed by mixing the electrode active material with the Li replenisher. It is preferable to mix the electrode active material with the Li replenisher before mixing other components. The coating area is preferably 10% or more of the active material particle surface area, more preferably 20% or more, and even more preferably 50% or more.

[0126] The electrode preferably further contains a conductive additive. Any known conductive material can be used as the conductive additive. Specific examples include metal materials such as copper and nickel, graphite such as natural graphite and artificial graphite, carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black, and carbon materials such as needle coke, carbon nanotubes, fullerenes, and amorphous carbon such as VGCF. These may be used alone or in any combination and ratio of two or more.

[0127] The content of the conductive additive in the electrode mixture is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and is usually 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. If the content is lower than this range, the conductivity may be insufficient. Conversely, if the content is higher than this range, the battery capacity may decrease.

[0128] The electrode may further contain a thermoplastic polymer. Examples of the thermoplastic polymer include polyvinylidene fluoride, vinylidene fluoride copolymer, polypropylene, polyethylene, polystyrene, polyethylene terephthalate, and polyethylene oxide. The thermoplastic polymer may be a resin or an elastomer. One type may be used alone, or two or more types may be used in any combination and ratio.

[0129] The ratio of the thermoplastic polymer to the electrode active material is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.10% by mass or more, and usually 3.0% by mass or less, preferably 2.5% by mass or less, more preferably 2.0% by mass or less. Adding a thermoplastic resin can improve the mechanical strength of the electrode. Furthermore, if the ratio exceeds this range, the ratio of the electrode active material in the electrode mixture decreases, which may cause problems such as a decrease in battery capacity or an increase in resistance between the active materials.

[0130] The positive electrode is preferably composed of a current collector and an electrode mixture sheet containing the positive electrode active material. Examples of materials for the positive electrode current collector include metals such as aluminum, titanium, tantalum, stainless steel, and nickel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly aluminum or its alloys, are preferred.

[0131] The density of the positive electrode mixture sheet is preferably 2.80 g / cm ３ More preferably, 3.00 g / cm ３ More preferably, 3.20 g / cm ３ or more, and preferably 3.80 g / cm ３ or less, more preferably 3.75 g / cm ３ More preferably, 3.70 g / cm or less ３ The range is as follows. If the temperature exceeds this range, cracks may easily occur within the sheet. If the temperature falls below this range, the conductivity between the active materials may decrease, increasing the battery resistance and making it difficult to obtain high output.

[0132] The thickness of the positive electrode is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the mixture layer minus the thickness of the metal foil of the current collector is preferably 10 μm or more, more preferably 20 μm or more, as a lower limit, and is also preferably 500 μm or less, more preferably 450 μm or less, on one side of the current collector.

[0133] The negative electrode is preferably composed of a current collector and an electrode mixture sheet containing the negative electrode active material. Examples of materials for the negative electrode current collector include metals such as copper, nickel, titanium, tantalum, and stainless steel, or alloys thereof; and carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly copper, nickel, and alloys thereof, are preferred.

[0134] The density of the negative electrode mixture sheet is preferably 1.3 g / cm ３ More preferably, 1.4 g / cm ３ More preferably, 1.5 g / cm ３ or more, and preferably 2.0 g / cm ３ or less, more preferably 1.9 g / cm３ More preferably, 1.8 g / cm or less ３ The range is as follows. If the temperature exceeds this range, cracks may easily occur within the sheet. If the temperature falls below this range, the conductivity between the active materials may decrease, increasing the battery resistance and making it difficult to obtain high output.

[0135] The thickness of the negative electrode is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the mixture layer minus the thickness of the metal foil of the current collector is preferably 10 μm or more, more preferably 20 μm or more, as a lower limit, and is also preferably 500 μm or less, more preferably 450 μm or less, on one side of the current collector.

[0136] Examples of the shape of the current collectors for the positive and negative electrodes include metal foil, expanded metal, punched metal, and foamed metal. Among these, metal foil is preferred. The metal foil may be formed into a mesh shape as appropriate. The thickness of the metal foil is optional, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and is usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the metal foil is thinner than this range, the strength required as a current collector may be insufficient. Conversely, if the metal foil is thicker than this range, handling may be impaired.

[0137] It is also preferable that the surface of the current collector is roughened in order to improve the adhesion between the current collector and the active material layer and reduce the electrical contact resistance. The surface roughness of the current collector, expressed as Sa (arithmetic mean height), is preferably about 260 nm or more, more preferably about 280 nm or more, and even more preferably about 300 nm or more.

[0138] In addition, it is also preferable that a conductive additive is applied to the surface of the current collector in order to reduce the electrical contact resistance between the current collector and the active material layer. Examples of the conductive additive include carbon and precious metals such as gold, platinum, and silver. Carbon is particularly preferable because of its light weight.

[0139] The positive electrode and the negative electrode may be produced by any conventional method, but the positive electrode and / or the negative electrode containing the fibrillating resin are preferably produced by a dry process, i.e., without preparing a slurry. Examples of such a method include a method in which an electrode mixture sheet produced by the method described below is laminated on a current collector via an adhesive, and then pressed.

[0140] An example of a specific method for producing an electrode mixture sheet containing a fibrillating resin as a binder is shown below. The electrode mixture sheet can be obtained by a production method including the steps of: (0) preparing a mixture containing an electrode active material and, if necessary, a conductive additive; (1) mixing a binder with the mixture obtained in the step (0) to prepare a composition for electrode preparation; (2) applying a shear force while mixing the composition for electrode preparation; (3) forming the electrode mixture obtained in the step (2) into a bulk shape; and (4) rolling the bulk electrode mixture obtained in the step (3) into a sheet shape.

[0141] In the above step (1), a fibrillating resin or a Li replenisher may be additionally added and mixed.

[0142] At the stage where shear force is applied while mixing the composition for electrode preparation in the above step (2), the resulting composition for electrode preparation is simply a mixture of the electrode active material, binder, etc. and exists in a formless state. Specific mixing methods include mixing methods using a drum mixer, a conical screw mixer, a single-screw kneader, a twin-screw kneader, a mix muller, a stirring mixer, a planetary mixer, a Henschel mixer, a high-speed mixer, etc.

[0143] In the above step (2), the mixing conditions may be appropriately set by the rotation speed and mixing time. For example, the rotation speed is preferably 5000 rpm or less. It is preferably 10 rpm or more, more preferably 15 rpm or more, and even more preferably 20 rpm or more. It is also preferably 4000 rpm or less, more preferably 3500 rpm or less, and even more preferably 3000 rpm. If the rotation speed is below the above range, mixing will take a long time, which will affect productivity. If the rotation speed is above the above range, fibrillation will proceed excessively, and the electrode mixture sheet may have poor strength and flexibility.

[0144] In the above step (3), forming into a bulk refers to forming the electrode-forming composition into a single mass. Specific methods for forming into a bulk include extrusion molding, press molding, and the like. The term "bulk" does not particularly specify a shape, and may refer to a single mass, including rods, sheets, spheres, cubes, and the like. The size of the mass is preferably such that the cross-sectional diameter or the shortest side is 10,000 μm or more, more preferably 20,000 μm or more.

[0145] Specific examples of the rolling method in the step (4) include rolling using a roll press, a plate press, a calender roll, or the like.

[0146] It is also preferable to include a step (5) after step (4), in which a larger load is applied to the obtained rolled sheet to roll it into an even thinner sheet. Repeating step (5) is also preferable. In this way, by rolling the rolled sheet little by little in stages rather than thinning it all at once, flexibility is improved. The number of times step (5) is performed is preferably 2 to 10 times, more preferably 3 to 9 times. Specific rolling methods include, for example, rotating two or more rolls and passing the rolled sheet between them to process it into an even thinner sheet. It is desirable to heat the sheet during rolling. The lower limit of the temperature range is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher. The upper limit is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. Heating softens the sheet, making it easier to roll.

[0147] From the viewpoint of adjusting the fibril diameter, it is also preferable to include a step (6) after step (4) or step (5) in which the rolled sheet is roughly crushed, re-formed into a bulk form, and rolled into a sheet. It is also preferable to repeat step (6). The number of times step (6) is performed is preferably from 1 to 12 times, more preferably from 2 to 11 times.

[0148] In step (6), specific methods for roughly crushing the rolled sheet and forming it into a bulk form include folding the rolled sheet, forming it into a rod or thin film sheet, chipping, etc. In the present disclosure, "rough crushing" means changing the form of the rolled sheet obtained in step (4) or step (5) into a different form in order to roll it into a sheet in the next step, and also includes simply folding the rolled sheet.

[0149] Furthermore, step (5) may be performed after step (6), or may be repeated. Furthermore, uniaxial or biaxial stretching may be performed in steps (3), (4), (5), and (6). Furthermore, the fibril diameter can be adjusted by the degree of crushing in step (6).

[0150] In the above steps (4), (5), or (6), the rolling ratio is preferably 10% or more, more preferably 20% or more, and preferably 80% or less, more preferably 65% ​​or less, and even more preferably 50% or less. If the rolling ratio is below the above range, the number of rolling operations increases, which takes more time and affects productivity. If the rolling ratio is above the above range, excessive fibrillation may occur, resulting in an electrode mixture sheet with poor strength and flexibility. The rolling ratio here refers to the reduction in thickness of the sample after rolling relative to the thickness before rolling. The sample before rolling may be a bulk electrode composition or a sheet electrode composition. The thickness of the sample refers to the thickness in the direction in which a load is applied during rolling.

[0151] The electrode mixture sheet can also be suitably produced by a production method comprising: step (a): mixing powder components (such as an electrode active material) and a binder to form an electrode mixture; and step (b): calendaring or extrusion-molding the electrode mixture to produce a sheet, wherein the mixing in step (a) comprises: (a1) homogenizing the powder components and the binder to form a powder; and (a2) mixing the powdered electrode-making composition obtained in step (a1) to prepare an electrode mixture.

[0152] For example, PTFE has two transition temperatures at about 19° C. and about 30° C. Below 19° C., PTFE can be easily mixed while maintaining its shape. However, above 19° C., the structure of the PTFE particles becomes looser and more sensitive to mechanical shear. At temperatures above 30° C., a greater degree of fibrillation occurs.

[0153] For this reason, the homogenization of (a1) is preferably carried out at a temperature of 19°C or lower, preferably 0°C to 19°C. That is, in such (a1), it is preferable to mix and homogenize while suppressing fibrillation. The subsequent mixing in (a2) is preferably carried out at a temperature of 30°C or higher to promote fibrillation.

[0154] Preferably, step (a2) is carried out at a temperature of 30° C. to 150° C., more preferably 35° C. to 120° C., even more preferably 40° C. to 100° C. In one embodiment, the calendering or extrusion of step (b) is carried out at a temperature between 30° C. and 150° C., preferably between 35° C. and 120° C., more preferably between 40° C. and 100° C.

[0155] The mixing in step (a) is preferably carried out while applying a shear force. Specific mixing methods include mixing using a drum mixer, a conical screw mixer, a single-screw kneader, a twin-screw kneader, a mix muller, a stirring mixer, a planetary mixer, a Henschel mixer, a high-speed mixer, etc.

[0156] The mixing conditions may be appropriately set by the rotation speed and mixing time. For example, the rotation speed is preferably 15,000 rpm or less. It is preferably 10 rpm or more, more preferably 50 rpm or more, even more preferably 100 rpm or more, and is preferably 12,000 rpm or less, more preferably 10,000 rpm or less, and even more preferably 8,000 rpm or less. If the rotation speed is below the above range, mixing will take a long time, which will affect productivity. If the rotation speed is above the above range, fibrillation will proceed excessively, which may result in an electrode mixture sheet with inferior strength. It is preferable to perform step (a1) with a weaker shear force than step (a2). It is also desirable to perform step (a1) for a shorter time than step (a2).

[0157] In the step (a2), the electrode-forming composition preferably does not contain a liquid solvent, but a small amount of a lubricant may be used. That is, a lubricant may be added to the powdered electrode-forming composition obtained in the step (a1) to prepare a paste.

[0158] The lubricant is not particularly limited, and examples thereof include water, ether compounds, alcohols, ionic liquids, carbonates, aliphatic hydrocarbons (low-polarity solvents such as heptane and xylene), isoparaffinic hydrocarbon compounds, and petroleum fractions (gasoline (C4-C10), naphtha (C4-C11), kerosene / paraffin (C10-C16), and mixtures thereof).

[0159] The lubricant preferably has a water content of 1000 ppm or less. A water content of 1000 ppm or less is preferable in that it reduces deterioration of the electrochemical device. The water content is more preferably 500 ppm or less.

[0160] When the above-mentioned lubricant is used, it is particularly preferable that the lubricant is a solvent with low polarity such as butyl butyrate, or an ether compound.

[0161] When the above-mentioned lubricant is used, the amount thereof may be 5.0 to 35.0 parts by weight, preferably 10.0 to 30.0 parts by weight, more preferably 15.0 to 25.0 parts by weight, based on the total weight of the composition subjected to step (a1).

[0162] Preferably, the electrode preparation composition substantially does not contain a liquid medium. Conventional electrode mixture formation methods generally involve preparing a slurry in which powders, which are electrode mixture components, are dispersed using a solvent containing a binder, and then applying and drying the slurry to prepare an electrode mixture sheet. In this case, a solvent that disperses or dissolves the binder is used. However, solvents that can dissolve binder resins that have been commonly used in the past are limited to specific solvents such as N-methylpyrrolidone. Because of their high polarity and the need for a drying process, the use of solvents incurs additional steps and costs. Furthermore, these solvents react with electrolytes, such as electrolytic solutions and solid electrolytes, degrading the electrolyte. Therefore, residual components during slurry preparation or after drying can cause a decrease in battery performance. Furthermore, low-polarity solvents such as heptane dissolve only a very limited number of binder resins, and their low flash points can make handling difficult.

[0163] By using a powder binder with low moisture content without using a solvent when forming the electrode mixture sheet, a battery with little electrolyte deterioration can be manufactured. Furthermore, in the manufacturing method described above, an electrode mixture sheet containing a binder with a fine fibrous structure can be manufactured, and by not preparing a slurry, the burden on the manufacturing process can be reduced.

[0164] Step (b) is calendering or extrusion. Calendering and extrusion can be performed by well-known methods. This allows the electrode mixture to be formed into the shape of an electrode mixture sheet. Step (b) preferably includes (b1) a step of forming the electrode mixture obtained by step (a) into a bulk form, and (b2) a step of calendering or extrusion-molding the bulk electrode mixture.

[0165] Forming into a bulk state means forming the electrode mixture into a single mass. Specific methods for forming into a bulk state include extrusion molding, press molding, and the like. The term "bulk state" does not particularly specify a shape, and may refer to a state in which the electrode mixture is in the form of a single mass, including rods, sheets, spheres, cubes, and the like. The size of the mass is preferably such that the diameter or the shortest side of its cross section is 10,000 μm or more, more preferably 20,000 μm or more.

[0166] Specific examples of the calendering or extrusion molding method in the step (b2) include a method of rolling the electrode mixture using a roll press, a calender roll machine, or the like.

[0167] The step (b) is preferably carried out at 30 to 150° C. As mentioned above, PTFE has a glass transition temperature around 30° C., and therefore, is easily fibrillated at temperatures above 30° C. Therefore, the step (b) is preferably carried out at such a temperature.

[0168] Furthermore, calendering or extrusion applies shear force, which causes the PTFE to fibrillate and form.

[0169] It is also preferable to have a step (c) after step (b) in which a larger load is applied to the obtained rolled sheet to roll it into an even thinner sheet. It is also preferable to repeat step (c). In this way, by rolling the rolled sheet little by little in stages rather than thinning it all at once, flexibility is improved. The number of times step (c) is performed is preferably from 2 to 10 times, and more preferably from 3 to 9 times. Specific rolling methods include, for example, a method in which two or more rolls are rotated and the rolled sheet is passed between them to process it into an even thinner sheet.

[0170] From the viewpoint of adjusting the sheet strength, it is also preferable to include a step (d) after step (b) or step (c) in which the rolled sheet is crushed, re-formed into a bulk form, and rolled into a sheet. It is also preferable to repeat step (d). The number of times step (d) is performed is preferably from 1 to 12 times, more preferably from 2 to 11 times.

[0171] In step (d), specific methods for crushing the rolled sheet and forming it into a bulk form include folding the rolled sheet, forming it into a rod or thin film sheet, chipping, etc. In the present disclosure, "crushing" means changing the form of the rolled sheet obtained in step (b) or (c) into another form in order to roll it into a sheet in the next step, and also includes simply folding the rolled sheet.

[0172] Furthermore, step (c) may be performed after step (d), or these steps may be repeated. Furthermore, uniaxial or biaxial stretching may be performed in steps (a), (b), (c), and (d). Furthermore, the sheet strength can be adjusted by the degree of crushing in step (d).

[0173] In the above steps (b), (c), or (d), the rolling ratio is preferably 10% or more, more preferably 20% or more, and preferably 80% or less, more preferably 65% ​​or less, and even more preferably 50% or less. If the rolling ratio is below the above range, the number of rolling operations increases, which increases the time required and affects productivity. If the rolling ratio is above the above range, excessive fibrillation may occur, resulting in an electrode mixture sheet with poor strength and flexibility. The rolling ratio here refers to the reduction in thickness of the sample after rolling relative to the thickness before rolling. The sample before rolling may be a bulk electrode composition or a sheet electrode composition. The thickness of the sample refers to the thickness in the direction in which a load is applied during rolling. The above steps (c) to (d) are preferably performed at 30°C or higher, more preferably 60°C or higher. Furthermore, they are preferably performed at 150°C or lower.

[0174] Examples of the electrochemical device of the present disclosure include a battery and a capacitor. Examples of the battery include a secondary battery such as a lithium ion battery. The capacitor is not particularly limited, but is preferably an electrochemical capacitor. Examples of the electrochemical capacitor include an electric double layer capacitor, a hybrid capacitor, and a redox capacitor. Examples of the hybrid capacitor include a sodium ion capacitor, a lithium ion capacitor, and a magnesium ion capacitor. Among these, an electric double layer capacitor is particularly preferred. The electrochemical device of the present disclosure is preferably a battery, more preferably a secondary battery, and even more preferably a lithium ion secondary battery.

[0175] The secondary battery may be a secondary battery that uses an electrolytic solution (electrolyte secondary battery) or a solid-state secondary battery. In this specification, the solid-state secondary battery may be a secondary battery that contains a solid electrolyte, may be a semi-solid-state secondary battery that contains a solid electrolyte and a liquid component as the electrolyte, or may be an all-solid-state secondary battery that contains only a solid electrolyte as the electrolyte.

[0176] The electrochemical device of the present disclosure is preferably an electrolyte secondary battery or an electrolyte capacitor. In the electrochemical device of the present disclosure, the positive electrode and / or negative electrode contain a Li replenisher, so that the initial capacity and capacity retention rate can be improved without adding an excessive amount of Li salt, which causes an increase in viscosity of the electrolyte. The electrolyte secondary battery or electrolyte capacitor can use the electrolyte, separator, etc., used in known secondary batteries or capacitors. The electrolyte secondary battery will be described in detail below.

[0177] The electrolyte is preferably a non-aqueous electrolyte, which may be prepared by dissolving a known electrolyte salt in a known organic solvent for dissolving electrolyte salts.

[0178] The organic solvent for dissolving the electrolyte salt is not particularly limited, and one or more of known hydrocarbon solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; and fluorine-based solvents such as fluoroethylene carbonate, fluoroether, and fluorinated carbonate can be used.

[0179] The electrolyte salt is, for example, LiClO ４ , LiAsF ６ , LiBF ４ , LiPF ６ , LiN(SO ２ CF ３ ) ２ , LiN(SO ２ C ２ F ５ ) ２ In particular, LiPF is preferred because of its excellent cycle characteristics. ６ , LiBF ４ , LiN(SO ２ CF ３ ) ２ , LiN(SO ２ C ２ F ５ ) ２ Or a combination of these is preferred.

[0180] The concentration of the electrolyte salt is preferably 0.8 mol / L or more, more preferably 1.0 mol / L or more. The upper limit depends on the organic solvent used to dissolve the electrolyte salt, but is usually 4.0 mol / L or less.

[0181] The electrolyte secondary battery preferably further includes a separator. The material and shape of the separator are not particularly limited as long as it is stable to the electrolyte and has excellent liquid retention properties, and any known separator can be used. Among these, it is preferable to use a material that is stable to the electrolyte, such as resin, glass fiber, or inorganic material, and that is in the form of a porous sheet or nonwoven fabric with excellent liquid retention properties.

[0182] The solid secondary battery is preferably an all-solid secondary battery. The solid secondary battery is preferably a lithium ion battery, and is also preferably a sulfide-based solid secondary battery. The solid secondary battery preferably includes a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode.

[0183] The solid electrolyte used in the solid secondary battery mixture may be a sulfide-based solid electrolyte or an oxide-based solid electrolyte. In particular, when a sulfide-based solid electrolyte is used, it has the advantage of being flexible.

[0184] The sulfide-based solid electrolyte is not particularly limited, and may be Li ２ S-P ２ S ５ , Li ２ S-P ２ S ３ , Li ２ S-P ２ S ３ -P ２ S ５ , Li ２ S-SiS ２ , LiI-Li ２ S-SiS ２ , LiI-Li ２ S-P ２ S ５ , LiI-Li ２ S-P ２ O ５ , LiI-Li ３ P.O. ４ -P２ S ５ , LiI-Li ２ S-SiS ２ -P ２ S ５ , Li ２ S-SiS ２ -Li ４ SiO ４ , Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ３ P.S. ４ -Li ４ GeS ４ , Li ３．４ P ０．６ Si ０．４ S ４ , Li ３．２５ P ０．２５ Ge ０．７６ S ４ , Li ４－ｘ Ge １－ｘ P ｘ S ４ (x=0.6~0.8), Li ４＋ｙ Ge １－ｙ Ga ｙ S ４ (y=0.2-0.3), LiPSCl, LiCl, Li ７－ｘ－２ｙ P.S. ６－ｘ－ｙ Cl ｘ (0.8≦x≦1.7, 0<y≦-0.25x+0.5), Li １０ SnP ２ S １２ Any one selected from the above, or a mixture of two or more thereof, can be used.

[0185] The sulfide-based solid electrolyte preferably contains lithium. Sulfide-based solid electrolytes containing lithium are used in solid-state batteries that use lithium ions as a carrier, and are particularly preferred in terms of electrochemical devices having high energy density.

[0186] The oxide-based solid electrolyte is preferably a compound that contains oxygen atoms (O), has the ionic conductivity of a metal belonging to Group 1 or 2 of the periodic table, and has electronic insulation properties.

[0187] Specific examples of the compound include Li ｘａ La ｙａ TiO ３ [xa=0.3~0.7, ya=0.3~0.7] (LLT), Li ｘｂ La ｙｂ Zr ｚｂ M ｂｂ ｍｂ O ｎｂ (M ｂｂ is at least one element selected from Al, Mg, Ca, Sr, V, Nb, Ta, Ti, Ge, In, and Sn, where xb satisfies 5≦xb≦10, yb satisfies 1≦yb≦4, zb satisfies 1≦zb≦4, mb satisfies 0≦mb≦2, and nb satisfies 5≦nb≦20.), Li ｘｃ B ｙｃ M ｃｃ ｚｃ O ｎｃ (M ｃｃ is at least one element selected from C, S, Al, Si, Ga, Ge, In, and Sn, where xc satisfies 0≦xc≦5, yc satisfies 0≦yc≦1, zc satisfies 0≦zc≦1, and nc satisfies 0≦nc≦6.), Li ｘｄ (Al, Ga) ｙｄ (Ti, Ge) ｚｄ Si ａｄ P ｍｄ O ｎｄ (where 1≦xd≦3, 0≦yd≦2, 0≦zd≦2, 0≦ad≦2, 1≦md≦7, 3≦nd≦15), Li （３－２ｘｅ） M ｅｅ ｘｅ D ｅｅ O(xe represents a number between 0 and 0.1, and M ｅｅ represents a divalent metal atom. ｅｅ represents a halogen atom or a combination of two or more halogen atoms.), Li ｘｆ Si ｙｆ O ｚｆ (1≦xf≦5, 0<yf≦3, 1≦zf≦10), Li ｘｇ S ｙｇ O ｚｇ (1≦xg≦3, 0<yg≦2, 1≦zg≦10), Li ３ BO ３ -Li ２ SO ４ , Li ２Alumni ２ O ３ -P ２ O ５ , Li ２ O—SiO ２ , Li ６ BaLa ２ Ta ２ O １２ , Li ３ P.O. （４－３／２ｗ） N ｗ (w is w<1), Li having a LISICON (Lithium super ionic conductor) type crystal structure ３．５ Zn ０．２５ GeO ４ , La having a perovskite crystal structure ０．５１ Li ０．３４ TiO ２．９４ , La ０．５５ Li ０．３５ TiO ３ , LiTi having a NASICON (sodium super ionic conductor) type crystal structure ２ P ３ O １２ , Li １＋ｘｈ＋ｙｈ (Al, Ga) ｘｈ (Ti, Ge) ２－ｘｈ Si ｙｈ P ３－ｙｈ O １２ (where 0≦xh≦1, 0≦yh≦1), Li having a garnet-type crystal structure ７ La ３ Zr ２ O １２ Also, ceramic materials in which elements are substituted for LLZ are known. For example, Li ６．２４ La ３ Zr ２ Al ０．２４ O １１．９８ , Li ６．２５ Al ０．２５ La ３ Zr ２ O １２ and Li substituted with Ta ６．６ La ３ Zr １．６ Ta ０．４ O １２, Nb-substituted Li ６．７５ La ３ Zr １．７５ Nb ０．２５ O １２ Other examples include LLZ-based ceramic materials in which at least one element of Mg (magnesium) and A (A is at least one element selected from the group consisting of Ca (calcium), Sr (strontium), and Ba (barium)) is substituted for LLZ. Phosphorus compounds containing Li, P, and O are also desirable. For example, lithium phosphate (Li ３ P.O. ４ ), LiPON, LiPOD, in which some of the oxygen in lithium phosphate is replaced with nitrogen １ (D １ is at least one selected from Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Ag, Ta, W, Pt, Au, etc. １ ON (A １ is at least one selected from Si, B, Ge, Al, C, Ga, etc.) can also be preferably used. ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -TiO ２ -GeO ２ , Li ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -TiO ２ etc.

[0188] The oxide-based solid electrolyte preferably contains lithium. The oxide-based solid electrolyte containing lithium is used in a solid-state battery that uses lithium ions as a carrier, and is particularly preferred in terms of electrochemical devices having a high energy density.

[0189] The oxide-based solid electrolyte is preferably an oxide having a crystalline structure. Oxides having a crystalline structure are particularly preferred in terms of good Li ion conductivity. Examples of oxides having a crystalline structure include perovskite-type (La ０．５１ Li ０．３４ TiO ２．９４ ), NASICON type (Li １．３ Al ０．３ Ti １．７ (P.O. ４ ) ３ etc.), garnet type (Li ７ La ３ Zr ２ O １２ (LLZ), etc. Among these, garnet type is preferred.

[0190] The volume-average particle size of the oxide-based solid electrolyte is not particularly limited, but is preferably 0.01 μm or more, and more preferably 0.03 μm or more. The upper limit is preferably 100 μm or less, and more preferably 50 μm or less. The average particle size of oxide-based solid electrolyte particles is measured using the following procedure. Oxide-based solid electrolyte particles are diluted with water (or heptane in the case of substances unstable in water) in a 20 ml sample bottle to prepare a 1 mass % dispersion. The diluted dispersion sample is irradiated with 1 kHz ultrasound for 10 minutes and used for testing immediately thereafter. Using this dispersion sample, data is acquired 50 times at 25°C using a quartz measurement cell using a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by HORIBA), to obtain the volume-average particle size. For other detailed conditions, please refer to the description in JIS Z8828:2013, "Particle Size Analysis - Dynamic Light Scattering Method," as necessary. Five samples are prepared for each level, and the average value is used.

[0191] The solid secondary battery may include a separator between the positive electrode and the negative electrode. Examples of the separator include a porous membrane such as polyethylene or polypropylene; a nonwoven fabric made of a resin such as polypropylene; and a nonwoven fabric such as a glass fiber nonwoven fabric.

[0192] The solid secondary battery may further include a battery case. The shape of the battery case is not particularly limited as long as it can accommodate the above-mentioned positive electrode, negative electrode, solid electrolyte layer, etc., but specific examples include a cylindrical shape, a square shape, a coin shape, and a laminate shape.

[0193] The solid secondary battery can be produced, for example, by stacking a positive electrode, a solid electrolyte layer sheet, and a negative electrode in this order and pressing them together.

[0194] The present disclosure also provides a composition comprising a Li replenisher and a fibrillating resin.

[0195] The composition of the present disclosure, having the above-described configuration, can improve the initial capacity and capacity retention rate of an electrochemical device. Furthermore, when in powder form, it can also improve flowability. The composition of the present disclosure can also be used in a dry process, eliminating the need to use a large amount of a dispersion medium such as water or an organic solvent, allowing for a wide selection of electrode active materials and solid electrolytes to be combined, which is advantageous in terms of the production process. It can also reduce the steps and costs associated with the use of a dispersion medium. Furthermore, the composition of the present disclosure has excellent binding strength with active materials and electrolytes, allowing for a reduction in the amount used.

[0196] The Li replenisher and fibrillating resin in the composition of the present disclosure can be the same as those described above for the electrochemical device of the present disclosure, and the preferred embodiments are also the same.

[0197] The content of the fibrillating resin in the composition of the present disclosure is preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, even more preferably 40% by mass or more, and is preferably 99% by mass or less, more preferably 97% by mass or less, even more preferably 90% by mass or less, even more preferably 85% by mass or less, even more preferably 80% by mass or less, even more preferably 75% by mass or less, and particularly preferably 70% by mass or less, in order to further improve the initial capacity and capacity retention rate of the electrochemical device and to further improve powder fluidity.

[0198] The mass ratio of the fibrillating resin to the Li replenisher (fibrillating resin / Li replenisher) is preferably 99 / 1 or less, more preferably 97 / 3 or less, even more preferably 90 / 10 or less, even more preferably 85 / 15 or less, even more preferably 80 / 20 or less, even more preferably 75 / 25 or less, particularly preferably 70 / 30 or less, and is preferably 20 / 80 or more, more preferably 30 / 70 or more, even more preferably 40 / 60 or more, even more preferably 45 / 55 or more, and particularly preferably 50 / 50 or more, in order to further improve the initial capacity and capacity retention rate of the electrochemical device and to further improve the powder fluidity.

[0199] The total amount of the fibrillating resin and the Li replenisher in the composition of the present disclosure is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more, and may also be less than 100% by mass, 99% by mass or less, or 97% by mass or less, in order to further improve the initial capacity and capacity retention rate of the electrochemical device and to further improve powder fluidity.

[0200] The composition of the present disclosure may contain other components as needed. Examples of other components include polymers other than the fibrillating resin, conductive materials, dispersants, thickeners, etc. For example, celluloses such as carboxymethyl cellulose (CMC) and methyl cellulose (MC) can be suitably used as thickeners.

[0201] The composition of the present disclosure may not contain an electrode active material or a solid electrolyte.

[0202] The composition of the present disclosure may contain at least one compound selected from the group consisting of a compound represented by the following general formula (1) (hereinafter also referred to as compound (1)) and a compound represented by the following general formula (2) (hereinafter also referred to as compound (2)). General formula (1): (H-(CF ２ ) ｍ－１ -COO) ｐ M １ (wherein m is 4 to 20. M １ represents H, a metal atom, NR ５ ４ (R ５ may be the same or different and are H or an organic group having 1 to 10 carbon atoms), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.) General formula (2): (H-(CF ２ ) ｎ -SO ３ ) ｑ M ２(wherein n is 4 to 20. M ２ is H, metal atom, NR ５ ４ (R ５ is the same as above), optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium. q is 1 or 2.

[0203] The above M １ and M ２ The metal atom as R may be a monovalent or divalent metal atom, such as an alkali metal (Group 1) or an alkaline earth metal (Group 2), and specific examples thereof include Na, K, and Li. ５ may be the same or different. ５ is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms. ５ The organic group as the aryl group is preferably an organic group containing no fluorine.

[0204] In general formula (1), m is preferably 6 or more, more preferably 8 or more, even more preferably 11 or more, even more preferably 13 or more, particularly preferably 15 or more, and is preferably 18 or less, more preferably 16 or less. In general formula (2), n is preferably 6 or more, more preferably 8 or more, even more preferably 11 or more, even more preferably 13 or more, particularly preferably 15 or more, and is preferably 18 or less, more preferably 16 or less.

[0205] The composition of the present disclosure may contain one or more types of compound (1), but may also contain two or more types, or may also contain three or more types.

[0206] When the composition of the present disclosure contains compound (1), the content of compound (1) (the content of each component when two or more types are present) may be 10 mass ppm or less, preferably 5000 mass ppb or less, more preferably 1000 mass ppb or less, even more preferably 500 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, and particularly preferably 10 mass ppb or less. The lower limit is not particularly limited, but may be 0.1 mass ppb or 1 mass ppb.

[0207] The composition of the present disclosure may contain one or more types of compound (2), but may also contain two or more types, or may also contain three or more types.

[0208] When the composition of the present disclosure contains compound (2), the content of compound (2) (the content of each component when two or more types are present) may be 10 mass ppm or less relative to the composition, preferably 5000 mass ppb or less, more preferably 1000 mass ppb or less, even more preferably 500 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 10 mass ppb or less, even more preferably 1 mass ppb or less, even more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantitation. The lower limit is not particularly limited, and may be an amount less than the lower limit of quantitation.

[0209] A composition containing compound (1) and / or (2) can be obtained by using a hydrocarbon surfactant. The composition of the present disclosure may contain a hydrocarbon surfactant in addition to the fibrillating resin, the Li / Na compound, and compound (1) and / or (2). The content of the hydrocarbon surfactant in the composition is not particularly limited, but is typically 100 ppm by mass to 10% by mass. In the hydrocarbon surfactant, the proportion of hydrogen atoms bonded to carbon atoms that are substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0210] The composition of the present disclosure preferably does not substantially contain a compound represented by the following general formula (3) (hereinafter also referred to as compound (3)). General formula (3): (H—(CF ２ ) ８ -SO ３ ) ｑ M ２ (In the formula, M ２ is H, metal atom, NR ５ ４ (R ５ may be the same or different and are H or an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent; and q is 1 or 2.

[0211] "Substantially free of compound (3)" means that the content of compound (3) is 25 mass ppb or less relative to the composition. The content of compound (3) is preferably 20 mass ppb or less relative to the composition, more preferably 15 mass ppb or less, and even more preferably 10 mass ppb or less. The lower limit is not particularly limited, but may be 0 mass ppb, 0.1 mass ppb, or 1 mass ppb.

[0212] The composition of the present disclosure preferably contains at least one compound selected from the group consisting of a compound represented by the following general formula (4) (hereinafter also referred to as compound (4)) and a compound represented by the following general formula (4') (hereinafter also referred to as compound (4')), and the content of each of these compounds is preferably 1000 ppb by mass or less relative to the composition. ２ ) １５ -COO) ｐ M １ (In the formula, M １ represents H, a metal atom, NR ５ ４ (R ５ may be the same or different and are H or an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine)), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.) General formula (4'): (H-(CF ２ ) １６ -COO) ｐ M １ (In the formula, M １ represents H, a metal atom, NR ５ ４ (R ５ is the same as above), optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium. p is 1 or 2.

[0213] When the composition of the present disclosure contains compound (4), the content of compound (4) is more preferably 500 mass ppb or less, even more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less, relative to the composition. The lower limit is not particularly limited, but may be 0.1 mass ppb or 1 mass ppb.

[0214] When the composition of the present disclosure contains compound (4'), the content of compound (4') is more preferably 500 mass ppb or less, even more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less, relative to the composition. The lower limit is not particularly limited, but may be 0.1 mass ppb or 1 mass ppb.

[0215] The composition of the present disclosure preferably contains at least one compound selected from the group consisting of a compound represented by the following general formula (5) (hereinafter also referred to as compound (5)) and a compound represented by the following general formula (5') (hereinafter also referred to as compound (5')), and the content of each of these compounds is preferably 1000 ppb by mass or less relative to the composition. ２ ) １３ -COO) ｐ M １ (In the formula, M １ represents H, a metal atom, NR ５ ４ (R ５ may be the same or different and are H or an organic group having 1 to 10 carbon atoms (preferably an organic group not containing fluorine)), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. p is 1 or 2.) General formula (5'): (H-(CF ２ ) １４ -COO) ｐ M １ (In the formula, M １ represents H, a metal atom, NR ５ ４ (R ５ is the same as above), optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium. p is 1 or 2.

[0216] When the composition of the present disclosure contains compound (5), the content of compound (5) is more preferably 500 mass ppb or less, even more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less, relative to the composition. The lower limit is not particularly limited, but may be 0.1 mass ppb or 1 mass ppb.

[0217] When the composition of the present disclosure contains compound (5'), the content of compound (5') is more preferably 500 mass ppb or less, even more preferably 250 mass ppb or less, even more preferably 100 mass ppb or less, even more preferably 50 mass ppb or less, even more preferably 25 mass ppb or less, even more preferably 15 mass ppb or less, and particularly preferably 10 mass ppb or less, relative to the composition. The lower limit is not particularly limited, but may be 0.1 mass ppb or 1 mass ppb.

[0218] The contents of the compounds (1), (2), (3), (4), (4'), (5) and (5') are values ​​measured by liquid chromatography mass spectrometry.

[0219] The composition of the present disclosure can be suitably used in a dry process. The amount of liquid relative to the composition is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, even more preferably 1% by mass or less, even more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less. Examples of the liquid include substances that are liquid at 25°C and 1 atm, such as water and organic solvents. The amount of liquid is measured by the following method. The mass of the composition is measured before and after heating in a vacuum at 100°C for 5 hours, and calculated according to the following formula. A sample is taken three times, and the values ​​are calculated for each, and the average is calculated and used. Amount of liquid (mass%) = [(mass (g) of composition before heating) - (mass (g) of composition after heating)] / (mass (g) of composition before heating) x 100

[0220] The composition of the present disclosure is preferably substantially free of organic solvents. This allows for reduction in steps and costs associated with the use of organic solvents. "Substantially free of organic solvents" means that the organic solvent content of the composition is 5% by mass or less. The organic solvent content is preferably 3% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably 0.001% by mass or less.

[0221] The composition of the present disclosure is preferably substantially free of moisture. This can suppress gas generation and deterioration of electrochemical device properties. Furthermore, a wide range of electrode active materials and solid electrolytes can be combined, which is advantageous in terms of production processes. Being substantially free of moisture means that the moisture content of the composition is 0.050% by mass or less. The moisture content is preferably 0.030% by mass or less, more preferably 0.010% by mass or less, even more preferably 0.005% by mass or less, even more preferably 0.003% by mass or less, even more preferably 0.002% by mass or less, and particularly preferably 0.001% by mass or less. The moisture content is measured by the following method. The mass of the composition is measured before and after heating at 150°C for 2 hours, and calculated according to the following formula. A sample is taken three times, and the values ​​are calculated for each sample, and the average is calculated. Water content (mass%)=[(mass (g) of composition before heating)−(mass (g) of composition after heating)] / (mass (g) of composition before heating)×100

[0222] The composition of the present disclosure preferably does not substantially contain fluorine-containing compounds having a molecular weight of 1000 or less. "Substantially free of fluorine-containing compounds" means that the amount of the fluorine-containing compounds is 25 mass ppb or less relative to the composition. The amount of the fluorine-containing compounds is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, even more preferably 10 mass ppb or less, even more preferably less than 10 mass ppb, even more preferably 1 mass ppb or less, even more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantitation. The lower limit is not particularly limited, and may be an amount less than the lower limit of quantitation.

[0223] The amount of the fluorine-containing compound having a molecular weight of 1,000 or less is measured by the following method. 1 g of sample is weighed, 10 g (12.6 ml) of methanol is added, and ultrasonic treatment is performed for 60 minutes to obtain an extract. The obtained extract is concentrated using a nitrogen purge as appropriate, and the fluorine-containing compounds in the concentrated extract are measured by LC / MS / MS. Molecular weight information is extracted from the obtained LC / MS spectrum, and a match with the structural formula of the candidate fluorine-containing compound is confirmed. Aqueous solutions with five or more levels of content of the standard substance are prepared, and LC / MS analysis is performed on the aqueous solutions with each content. The relationship between the content and the area area relative to that content is plotted, and a calibration curve is drawn. Using the calibration curve, the area area of ​​the LC / MS chromatogram of the fluorine-containing compound in the extract is converted to the content of the fluorine-containing compound. The lower limit of quantitation in this measurement method is 10 ppb by mass.

[0224] Examples of the fluorine-containing compound having a molecular weight of 1000 or less include fluorine-containing compounds having a hydrophilic group with a molecular weight of 1000 g / mol or less. The molecular weight of the fluorine-containing compound is preferably 800 or less, more preferably 500 or less. Polymer particles obtained by polymerization in the presence of a fluorine-containing surfactant usually contain a fluorine-containing surfactant in addition to the target polymer. In this specification, the fluorine-containing surfactant is used during polymerization. The fluorine-containing compound having a molecular weight of 1000 or less may be a compound that is not added during polymerization, for example, a compound that is by-produced during polymerization. Note that, when the fluorine-containing compound having a molecular weight of 1000 or less contains an anionic moiety and a cationic moiety, it means a fluorine-containing compound in which the molecular weight of the anionic moiety is 1000 or less. The fluorine-containing compound having a molecular weight of 1000 or less does not include fibrillating resins.

[0225] Examples of the hydrophilic group include -COOM and -SO ２ M or -SO ３ M, -COOM, -SO ３ M (in each formula, M is H, a metal atom, NR １ ４, optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R １ is H or an organic group.

[0226] As the fluorine-containing surfactant, a surfactant containing fluorine (anionic fluorine-containing surfactant) in which the molecular weight of the anionic part is 1000 or less can also be used. The "anionic part" means the part of the fluorine-containing surfactant excluding the cation. For example, F(CF ２ ) ｎ１ In the case of COOM, "F(CF ２ ) ｎ１ The anionic fluorine-containing surfactant is a surfactant represented by the following general formula (N ０ ): X ｎ０ -Rf ｎ０ -Y ０ (N ０ ) (wherein, X ｎ０ is H, Cl or F. ｎ０ is a linear, branched or cyclic alkylene group having 3 to 20 carbon atoms, in which some or all of the H atoms are substituted with F, and the alkylene group may contain one or more ether bonds, and some of the H atoms may be substituted with Cl. ０ is an anionic group. ０ The anionic group is -COOM, -SO ２ M or -SO ３ M, -COOM or -SO ３ M. M may be H, a metal atom, NR １ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R １ is H or an organic group. The metal atom includes alkali metals (Group 1), alkaline earth metals (Group 2), etc., such as Na, K, or Li. １ As the group, H or C １－１０ and may be an organic group of the formula: １－４and may be an organic group of the formula: １－４ M may be H, a metal atom, or an alkyl group of the formula NR １ ４ may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR １ ４ may be H, Na, K, Li or NH ４ The above Rf ｎ０ may be one in which 50% or more of H is substituted with fluorine.

[0227] The above fluorine-containing surfactant may be one type of fluorine-containing surfactant or a mixture containing two or more types of fluorine-containing surfactants.

[0228] Examples of the fluorine-containing surfactant include compounds represented by the following formula: F(CF ２ ) ７ COOM, F(CF ２ ) ５ COOM, C.F. ３ O (CF ２ ) ３ OCHFCF ２ COOM, C. ３ F ７ OCF (CF ３ )CF ２ OCF (CF ３ ) COOM, C.F. ３ CF ２ CF ２ OCF (CF ３ ) COOM, C.F. ３ CF ２ OCF ２ CF ２ OCF ２ COOM, C. ２ F ５ OCF (CF ３ )CF ２ OCF (CF ３ ) COOM, C.F. ３ OCF (CF ３ )CF ２ OCF (CF ３ ) COOM, C.F. ２ ClCF ２CF ２ OCF (CF ３ )CF ２ OCF ２ COOM, C.F. ２ ClCF ２ CF ２ OCF ２ CF (CF ３ ) OCF ２ COOM, C.F. ２ ClCF(CF ３ ) OCF (CF ３ )CF ２ OCF ２ COOM, C.F. ２ ClCF(CF ３ ) OCF ２ CF (CF ３ ) OCF ２ COOM, and (In each formula, M is H, metal atom, NR １ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium. １ is H or an organic group.) The compositions of the present disclosure are preferably substantially free of any of the fluorine-containing compounds represented by the above formulas.

[0229] In each of the above formulas, M is H, a metal atom, or NR １ ４ may be H, an alkali metal (Group 1), an alkaline earth metal (Group 2), or NR １ ４ may be H, Na, K, Li or NH ４ R １ is H or C １－１０ and may be an organic group of the formula: １－４ and may be an organic group of the formula: １－４ The alkyl group may be:

[0230] When the composition of the present disclosure is substantially free of any of the fluorine-containing compounds represented by the above formulas, gas generation and deterioration of electrochemical device properties can be further suppressed. "Substantially free of any of the fluorine-containing compounds represented by the above formulas" means that the amount of the fluorine-containing compounds is 25 mass ppb or less relative to the composition. The amount of the fluorine-containing compounds is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, even more preferably 10 mass ppb or less, even more preferably less than 10 mass ppb, even more preferably 1 mass ppb or less, even more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantitation. The lower limit is not particularly limited, and may be an amount less than the lower limit of quantitation.

[0231] The compositions of the present disclosure have the following general formula: ｎ－１ F ２ｎ－１ COO － ]M ＋ (wherein n is an integer of 9 to 14, preferably an integer of 9 to 12; M ＋ It is also preferable that the composition is substantially free of a fluorine-containing compound represented by the formula (I). This makes it possible to further suppress gas generation and deterioration of the electrochemical device properties. ＋ The M constituting the formula is the same as the M described above. Substantially free of fluorine-containing compounds represented by the formula means that the amount of the fluorine-containing compounds is 25 mass ppb or less relative to the composition. The amount of the fluorine-containing compounds is preferably 20 mass ppb or less, more preferably 15 mass ppb or less, even more preferably 10 mass ppb or less, even more preferably less than 10 mass ppb, even more preferably 1 mass ppb or less, even more preferably less than 1 mass ppb, and particularly preferably less than the lower limit of quantitation. The lower limit is not particularly limited, and may be an amount less than the lower limit of quantitation.

[0232] The composition of the present disclosure preferably has an endothermic peak temperature of 333°C or higher, more preferably 335°C or higher, even more preferably 337°C or higher, even more preferably 340°C or higher, and preferably 350°C or lower, more preferably 346°C or lower, in order to form a mixture sheet having even greater strength. The endothermic peak temperature is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry (DSC) at a heating rate of 10°C / min on a composition that has not had a history of being heated to a temperature of 300°C or higher. When there are two or more minimum points in one melting peak, each of these is taken as the endothermic peak temperature.

[0233] The composition of the present disclosure preferably has a melting point of 315° C. or higher, more preferably 320° C. or higher, even more preferably 323° C. or higher, and even more preferably 325° C. or higher, and preferably 335° C. or lower, and more preferably 330° C. or lower, in order to form a composite sheet having even greater strength. The melting point is the temperature corresponding to the minimum point in the heat of fusion curve obtained by performing differential scanning calorimetry (DSC) on a composition that has a history of being heated to a temperature of 300° C. or higher at a heating rate of 10° C. / min.

[0234] The composition of the present disclosure may have an average secondary particle size of 350 μm or more, preferably 400 μm or more, more preferably 450 μm or more, even more preferably 500 μm or more, even more preferably 550 μm or more, and particularly preferably 600 μm or more, and is preferably 1000 μm or less, more preferably 900 μm or less, even more preferably 800 μm or less, and even more preferably 700 μm or less. The average secondary particle size is measured in accordance with JIS K 6891.

[0235] In terms of excellent handleability, the composition of the present disclosure may have an average aspect ratio of 2.0 or less, preferably 1.8 or less, more preferably 1.7 or less, even more preferably 1.6 or less, even more preferably 1.5 or less, even more preferably 1.4 or less, especially preferably 1.3 or less, particularly preferably 1.2 or less, and most preferably 1.1 or less. The average aspect ratio may also be 1.0 or more. The average aspect ratio is determined by observing the composition with a scanning electron microscope (SEM), processing images of 200 or more randomly selected particles, and averaging the ratios of their major axis and minor axis.

[0236] In terms of excellent handleability, the composition of the present disclosure preferably has an apparent density of 0.40 g / ml or more, more preferably 0.43 g / ml or more, even more preferably 0.45 g / ml or more, even more preferably 0.48 g / ml or more, and particularly preferably 0.50 g / ml or more. The upper limit is not particularly limited, but may be 0.70 g / ml. The apparent density is measured in accordance with JIS K 6892.

[0237] The form of the composition of the present disclosure is not limited, but is preferably a powder in that it can be mixed with an electrode active material and a solid electrolyte without using a large amount of a dispersion medium. Note that the composition may be in a form other than a powder, such as a dispersion liquid or a molded product.

[0238] The composition of the present disclosure can be produced by mixing a fibrillating resin with a Li replenisher. By mixing the fibrillating resin with the Li replenisher before mixing with an electrode active material or a solid electrolyte, the powder fluidity of the composition is improved, improving handleability. Furthermore, by improving the dispersibility of the fibrillating resin, the fibrillating resin and the Li replenisher are uniformly dispersed when mixed with an electrode active material or a solid electrolyte to produce a composite, thereby improving the initial capacity, capacity retention rate, and other electrochemical device properties.

[0239] The method for mixing the fibrillating resin and the Li replenisher is not limited, but dry mixing is preferred. The fibrillating resin and the Li replenisher are preferably mixed in powder form. Mixing can be performed using, for example, an air mixer, a V-type mixer, a conical screw mixer, or the like.

[0240] The raw material fibrillating resin can be suitably produced, for example, by a production method including the steps of (A) obtaining an aqueous dispersion of the fibrillating resin, (B) coagulating the aqueous dispersion to obtain a wet powder, and (C) drying (heat treating) the wet powder.

[0241] The aqueous dispersion in step (A) can be produced by emulsion polymerization. The emulsion polymerization can be carried out by a known method. For example, an aqueous dispersion containing particles (primary particles) of the fibrillating resin can be obtained by emulsion polymerization of monomers necessary for constituting the fibrillating resin in an aqueous medium in the presence of an anionic surfactant and a polymerization initiator. In the emulsion polymerization, chain transfer agents, buffers, pH adjusters, stabilizing aids, dispersion stabilizers, radical scavengers, etc. may be used as needed.

[0242] The emulsion polymerization is preferably carried out in the presence of a hydrocarbon surfactant. A method for producing a TFE polymer by emulsion polymerization using a hydrocarbon surfactant will be described in detail below.

[0243] In the hydrocarbon surfactant, the proportion of hydrogen atoms bonded to carbon atoms that are substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms at all).

[0244] The hydrocarbon surfactant is preferably a carboxylic acid type hydrocarbon surfactant. The carboxylic acid type hydrocarbon surfactant is not limited as long as it has a carboxy group (—COOH) or a group in which the hydrogen atom of the carboxy group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.), and for example, a hydrocarbon surfactant having a carboxy group or a group in which the hydrogen atom of the carboxy group is substituted with an inorganic cation can be used from among the specific hydrocarbon surfactants described below and other compounds having surface activity.

[0245] The hydrocarbon surfactant is preferably a sulfonic acid hydrocarbon surfactant. ３ H group, -OSO ３ The surfactant is not limited as long as it has an H group or a group in which the hydrogen atom of such a group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.), and examples thereof include —SO ３ H group, -OSO ３ Hydrocarbon surfactants having an H group or a group in which the hydrogen atom of such a group is substituted with an inorganic cation can be used.

[0246] The hydrocarbon surfactant is preferably water-soluble in view of improving emulsification performance. The hydrocarbon surfactant being water-soluble means that the maximum concentration in water at which the hydrocarbon surfactant dissolves at 85°C is 100 mass ppm or more. The maximum concentration in water is preferably 500 mass ppm or more, more preferably 1000 mass ppm or more, even more preferably 2000 mass ppm or more, even more preferably 3000 mass ppm or more, even more preferably 5000 mass ppm or more, even more preferably 1 mass% or more, even more preferably 3 mass% or more, even more preferably 5 mass% or more, particularly preferably 10 mass% or more, and may be 50 mass% or less.

[0247] The emulsion polymerization preferably includes a step of carrying out emulsion polymerization of tetrafluoroethylene alone, or emulsion polymerization of tetrafluoroethylene and a modified monomer copolymerizable with tetrafluoroethylene, in an aqueous medium in the presence of a specific hydrocarbon surfactant, and a step of continuously adding the specific hydrocarbon surfactant in the above step.

[0248] The continuous addition of a specific hydrocarbon surfactant means, for example, adding the specific hydrocarbon surfactant over time, without interruption, or in portions, rather than all at once. The specific hydrocarbon surfactant is, for example, a hydrocarbon surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxy groups), or a hydrocarbon surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxy groups) that has been subjected to radical treatment or oxidation treatment. The radical treatment may be any treatment that generates radicals in a hydrocarbon surfactant having one or more carbonyl groups (excluding carbonyl groups in carboxy groups). For example, the radical treatment may be a treatment in which deionized water and a hydrocarbon surfactant are added to a reactor, the reactor is sealed, the system is purged with nitrogen, the reactor is heated and pressurized, a polymerization initiator is added, the mixture is stirred for a certain period of time, and the reactor is depressurized to atmospheric pressure and then cooled. Above-mentioned oxidation treatment is the treatment that oxidizing agent is added to hydrocarbon surfactant that has one or more carbonyl groups (but excluding the carbonyl group in carboxyl group).As oxidizing agent, for example, oxygen, ozone, hydrogen peroxide water, manganese oxide (IV), potassium permanganate, potassium dichromate, nitric acid, sulfur dioxide etc. can be enumerated.By above-mentioned production method, even if no conventional fluorine-containing surfactant is used, it is possible to produce TFE polymer that has the same molecular weight as that of the production method that uses conventional fluorine-containing surfactant.

[0249] In the above-mentioned production method, the step of continuously adding the specific hydrocarbon surfactant is preferably that when the solid content of the TFE polymer formed in aqueous medium is less than 0.60 mass%, the hydrocarbon surfactant is started to be added into aqueous medium.When the solid content is 0.5 mass% or less, the specific hydrocarbon surfactant is preferably started to be added into aqueous medium.When the solid content is 0.3 mass% or less, the specific hydrocarbon surfactant is more preferably started to be added when the solid content is 0.2 mass% or less, even more preferably started to be added when the solid content is 0.1 mass% or less, and particularly preferably started to be added at the start of polymerization.The solid content is the concentration relative to the total of aqueous medium and TFE polymer.

[0250] In the step of continuously adding the specific hydrocarbon surfactant, the amount of the specific hydrocarbon surfactant added is preferably 0.01 to 10% by mass relative to 100% by mass of the aqueous medium, more preferably 0.05% by mass at the lower limit, even more preferably 0.1% by mass at the lower limit, more preferably 5% by mass at the upper limit, and even more preferably 1% by mass at the upper limit.

[0251] In the process of emulsion polymerization of tetrafluoroethylene alone or emulsion polymerization of tetrafluoroethylene and a modified monomer copolymerizable with tetrafluoroethylene in an aqueous medium in the presence of the specific hydrocarbon surfactant, the amount of the specific hydrocarbon surfactant is preferably large, and is preferably 0.0001 to 10 mass% relative to 100 mass% of the aqueous medium.A more preferred lower limit is 0.001 mass%, and a more preferred upper limit is 1 mass%.If it is less than 0.0001 mass%, the dispersing force may be insufficient, and if it exceeds 10 mass%, the effect commensurate with the amount cannot be obtained, and instead, the polymerization rate may decrease or the reaction may stop.The amount of the specific hydrocarbon surfactant is appropriately determined depending on the type of monomer used, the molecular weight of the target TFE polymer, etc.

[0252] The specific hydrocarbon surfactants include those represented by the formula: R-X (wherein R is a fluorine-free organic group having 1 to 2000 carbon atoms and one or more carbonyl groups (excluding carbonyl groups in carboxy groups), and X is -OSO ３ X １ , -COOX １ or -SO ３ X １ (X １ represents H, a metal atom, NR １ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R １ is H or an organic group (preferably an organic group not containing fluorine), and may be the same or different. )) and at least one selected from the group consisting of surfactants (e) described below are preferred. R preferably has 500 or less carbon atoms, more preferably 100 or less, even more preferably 50 or less, and even more preferably 30 or less. The specific hydrocarbon surfactant is preferably a surfactant represented by the following formula (a): (In the formula, R １ａ is a linear or branched alkyl group having 1 or more carbon atoms or a cyclic alkyl group having 3 or more carbon atoms, in which a hydrogen atom bonded to a carbon atom may be substituted with a monovalent organic group containing a hydroxy group or an ester bond (preferably an organic group not containing fluorine), and when it has 2 or more carbon atoms, it may contain a carbonyl group, and when it has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ａ and R ３ａ are independently a single bond or a divalent linking group. １ａ , R ２ａ and R ３ａ has a total of 6 or more carbon atoms. ａ represents H, a metal atom, NR ４ａ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ４ａare H or organic groups (preferably fluorine-free organic groups), and may be the same or different. １ａ , R ２ａ and R ３ａ any two of which may be bonded to each other to form a ring; a surfactant (a) represented by the following formula (b): (In the formula, R １ｂ R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when the alkyl group has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ｂ and R ４ｂ are independently H or a substituent. ３ｂ is an alkylene group having 1 to 10 carbon atoms which may have a substituent. n is an integer of 1 or more. p and q are independently integers of 0 or more. X ｂ represents H, a metal atom, NR ５ｂ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ５ｂ are H or organic groups (preferably fluorine-free organic groups), and may be the same or different. １ｂ , R ２ｂ , R ３ｂ and R ４ｂ Any two of the groups may be bonded to each other to form a ring. L represents a single bond, —CO ２ -B-*, -OCO-B-*, -CONR ６ｂ -B-*, -NR ６ｂ CO-B-* or -CO- (where -CO ２ -B-, -OCO-B-, -CONR ６ｂ -B-, -NR ６ (excluding the carbonyl group contained in CO—B—), B is a single bond or an alkylene group having 1 to 10 carbon atoms which may have a substituent, and R ６ｂ is H or an alkyl group having 1 to 4 carbon atoms which may have a substituent. * represents -OSO ３ X ｂ (b) a surfactant represented by the following formula (c): (In the formula, R １ｃ is a linear or branched alkyl group having 1 or more carbon atoms or a cyclic alkyl group having 3 or more carbon atoms, in which a hydrogen atom bonded to a carbon atom may be substituted with a monovalent organic group containing a hydroxy group or an ester bond (preferably an organic group not containing fluorine), and when it has 2 or more carbon atoms, it may contain a carbonyl group, and when it has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ｃ and R ３ｃ are independently a single bond or a divalent linking group. １ｃ , R ２ｃ and R ３ｃ has a total of 5 or more carbon atoms. ｃ Ha, -COOX ｃ or -SO ３ X ｃ (X ｃ represents H, a metal atom, NR ４ｃ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ４ｃ R is H or an organic group (preferably an organic group not containing fluorine), and may be the same or different. １ｃ , R ２ｃ and R ３ｃ any two of which may be bonded to each other to form a ring; a surfactant (c) represented by the following formula (d): (In the formula, R １ｄ R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when the alkyl group has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or form a ring. ２ｄ and R ４ｄ are independently H or a substituent. ３ｄ is an alkylene group having 1 to 10 carbon atoms which may have a substituent. n is an integer of 1 or more. p and q are independently integers of 0 or more. A ｄ is -SO ３ X ｄ or -COOX ｄ (X ｄrepresents H, a metal atom, NR ５ｄ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R ５ｄ R is H or an organic group (preferably an organic group not containing fluorine), and may be the same or different. １ｄ , R ２ｄ , R ３ｄ and R ４ｄ Any two of the groups may be bonded to each other to form a ring. L represents a single bond, —CO ２ -B-*, -OCO-B-*, -CONR ６ｄ -B-*, -NR ６ｄ CO-B-* or -CO- (where -CO ２ -B-, -OCO-B-, -CONR ６ｄ -B-, -NR ６ｄ (excluding the carbonyl group contained in CO—B—), B is a single bond or an alkylene group having 1 to 10 carbon atoms which may have a substituent, and R ６ｄ is H or an alkyl group having 1 to 4 carbon atoms which may have a substituent. ｄ and a surfactant (d) represented by the following formula (e): (In the formula, R １ｅ ~R ５ｅ represents H or a monovalent substituent, provided that R １ｅ and R ３ｅ At least one of the groups represented by the general formula: -Y ｅ -R ６ｅ a group represented by R ２ｅ and R ５ｅ At least one of the groups represented by the general formula: -X ｅ -A ｅ or a group represented by the general formula: -Y ｅ -R ６ｅ In addition, X represents a group represented by the formula: ｅ A is the same or different in each occurrence and is a divalent linking group or bond; ｅ is the same or different in each occurrence and represents -COOM ｅ , -SO ３ M ｅ or -OSO３ M ｅ (M ｅ represents H, a metal atom, NR ７ｅ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, R ７ｅ is H or an organic group (preferably an organic group not containing fluorine); Y ｅ is the same or different in each occurrence and represents -S(=O) ２ -, -O-, -COO-, -OCO-, -CONR ８ｅ - and -NR ８ｅ a divalent linking group selected from the group consisting of CO—, or a bond, R ８ｅ is H or an organic group (preferably a fluorine-free organic group); R ６ｅ R may be the same or different in each occurrence and represents an alkyl group having two or more carbon atoms which may contain at least one group selected from the group consisting of a carbonyl group, an ester group, an amide group and a sulfonyl group between carbon atoms; １ｅ ~R ５ｅ Any two of the groups may be bonded to each other to form a ring.

[0253] The surfactant (a) can be produced, for example, by the production method described in WO 2020 / 022355.

[0254] The surfactant (b) can be produced, for example, by the production method described in WO 2020 / 022355.

[0255] The surfactant (c) can be produced, for example, by the production method described in WO 2020 / 022355.

[0256] The surfactant (d) can be produced, for example, by the production method described in WO 2020 / 022355.

[0257] The surfactant (e) can be produced by a known production method.

[0258] The specific hydrocarbon surfactant is also preferably a carboxylic acid hydrocarbon surfactant. The carboxylic acid hydrocarbon surfactant is not limited as long as it has a carboxy group (-COOH) or a group in which the hydrogen atom of the carboxy group is substituted with an inorganic cation (e.g., a metal atom, ammonium, etc.). For example, from the specific hydrocarbon surfactants described above, a hydrocarbon surfactant having a carboxy group or a group in which the hydrogen atom of the carboxy group is substituted with an inorganic cation can be used. In the carboxylic acid hydrocarbon surfactant, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0259] The carboxylic acid type hydrocarbon surfactant is preferably at least one selected from the group consisting of surfactant (c) represented by the above formula (c) and surfactant (d) represented by the above formula (d), which has a carboxy group (—COOH) or a group in which the hydrogen atom of the carboxy group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.).

[0260] The specific hydrocarbon surfactant is also preferably a sulfonic acid hydrocarbon surfactant. ３ H group, -OSO ３ There are no particular limitations on the surfactants as long as they have an H group or a group in which the hydrogen atom of such a group is substituted with an inorganic cation (for example, a metal atom, ammonium, etc.), and examples thereof include, from the specific hydrocarbon surfactants described above, -SO ３ H group, -OSO ３ Hydrocarbon surfactants having an H group or a group in which the hydrogen atoms of these groups have been substituted with inorganic cations can be used. In the sulfonic acid hydrocarbon surfactant, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms at all).

[0261] The TFE polymer composition of the present disclosure can be produced efficiently by using at least one of the above-mentioned specific hydrocarbon surfactants.In addition, the TFE polymer composition of the present disclosure can be produced by simultaneously using two or more of the above-mentioned specific hydrocarbon surfactants, or can be produced by simultaneously using other surfactant compounds other than the above-mentioned specific hydrocarbon surfactants, as long as they have volatility or can remain in the molded article etc. that is made of TFE polymer.

[0262] As the other compounds having surface activity, for example, those described in JP-T-2013-542308, JP-T-2013-542309, and JP-T-2013-542310 can be used.

[0263] The other surfactant compounds may be surfactants having a hydrophilic portion and a hydrophobic portion on the same molecule, such as hydrocarbon surfactants (excluding the specific hydrocarbon surfactants described above). These may be cationic, nonionic, or anionic. In the compounds described above, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0264] Cationic surfactants typically have a positively charged hydrophilic portion, such as an alkylated ammonium halide, such as an alkylated ammonium bromide, and a hydrophobic portion, such as a long-chain fatty acid. In the cationic surfactant, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0265] Anionic surfactants typically have a hydrophilic portion such as a carboxylate, sulfonate, or sulfate, and a hydrophobic portion that is a long-chain hydrocarbon portion such as an alkyl. In the anionic surfactant, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0266] Nonionic surfactants generally do not contain charged groups and have a hydrophobic portion that is a long hydrocarbon chain. The hydrophilic portion of the nonionic surfactant contains a water-soluble functional group, such as an ethylene ether chain derived from polymerization with ethylene oxide. In the nonionic surfactant, the proportion of hydrogen atoms bonded to carbon atoms that are substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0267] Other compounds having surface activity include R-L-M (wherein R is a linear or branched alkyl group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group having 3 or more carbon atoms which may have a substituent, and when R has 3 or more carbon atoms, it may contain a monovalent or divalent heterocycle or may form a ring; L is -ArSO ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － and M is H, a metal atom, or NR ５ ４ (R ５ may be the same or different and are H or an organic group (preferably an organic group not containing fluorine)), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. ３ － is an aryl sulfonate. ５is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms. Specifically, CH ３ - (CH ２ ) ｎ -LM (wherein n is an integer of 6 to 17, and L and M are the same as above). Mixtures in which R is an alkyl group having 12 to 16 carbon atoms and L-M is sulfate or sodium dodecyl sulfate (SDS) can also be used. Other surfactant compounds include those represented by R ６ (-L-M) ２ (In the formula, R ６ is a linear or branched alkylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkylene group having 3 or more carbon atoms which may have a substituent, and when the number of carbon atoms is 3 or more, it may contain a monovalent or divalent heterocycle or may form a ring. ３ － , -SO ３ － , -SO ４ -, -PO ３ － or -COO － and M is H, a metal atom, or NR ５ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, R ５ is H or an organic group (preferably an organic group not containing fluorine), -ArSO ３ － is an aryl sulfonate. ) Other examples of compounds having surface activity include anionic surfactants represented by the formula: R ７ (-L-M) ３ (In the formula, R ７ is a linear or branched alkylidyne group having 1 or more carbon atoms which may have a substituent, or a cyclic alkylidyne group having 3 or more carbon atoms which may have a substituent, and when the number of carbon atoms is 3 or more, it may contain a monovalent or divalent heterocycle or may form a ring. ３ － , -SO３ － , -SO ４ -, -PO ３ － or -COO － and M is H, a metal atom, or NR ５ ４ , optionally substituted imidazolium, optionally substituted pyridinium or optionally substituted phosphonium, R ５ is H or an organic group (preferably an organic group not containing fluorine). ３ － is an aryl sulfonate.

[0268] Examples of siloxane hydrocarbon surfactants include those described in Silicone Surfactants, R. M. Hill, Marcel Dekker, Inc., ISBN: 0-8247-00104. The structure of the siloxane surfactant comprises a distinct hydrophobic portion and a hydrophilic portion. The hydrophobic portion comprises one or more dihydrocarbylsiloxane units, in which the substituents on the silicone atoms are entirely hydrocarbon. These siloxane surfactants can also be considered hydrocarbon surfactants in the sense that the carbon atoms of the hydrocarbyl groups are entirely substituted with hydrogen atoms, although these may be substituted with halogens such as fluorine; that is, the monovalent substituents on the carbon atoms of the hydrocarbyl groups are hydrogen. In the above siloxane surfactants, the proportion of hydrogen atoms bonded to carbon atoms substituted with fluorine atoms is preferably 50% or less, more preferably 25% or less, even more preferably 10% or less, and most preferably 0% (no substitution with fluorine atoms).

[0269] Siloxane hydrocarbon surfactants are also disclosed in US Pat. No. 6,841,616.

[0270] The other surfactant compound is preferably an anionic hydrocarbon surfactant. As the anionic hydrocarbon surfactant, those described above can be used, but for example, the following hydrocarbon surfactants can be suitably used.

[0271] Examples of the anionic hydrocarbon surfactant include those represented by the following formula (α): １００ -COOM (α) (wherein, R １００ is a monovalent organic group containing one or more carbon atoms (preferably an organic group not containing fluorine); M is H, a metal atom, NR １０１ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R １０１ R is H or an organic group (preferably an organic group not containing fluorine), and may be the same or different. １０１ The organic group in R is preferably an alkyl group. １０１ is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms. １００ The number of carbon atoms in R is preferably 2 or more, and more preferably 3 or more. １００ The number of carbon atoms in is preferably 29 or less, more preferably 23 or less. The metal atom of M includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. M is H, a metal atom, or NR １０１ ４ is preferred, and H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR １０１ ４ is more preferred, and H, Na, K, Li or NH ４ is more preferred, Na, K or NH ４ is even more preferred, Na or NH ４ is particularly preferred, and NH ４ is most preferred.

[0272] The compound (α) may be R １０２ -COOM (in the formula, R １０２is a linear or branched alkyl group, alkenyl group, alkylene group or alkenylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group or alkenylene group having 3 or more carbon atoms which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocycle or may form a ring. M is the same as above. ) are also included. Specifically, CH ３ - (CH ２ ) ｎ -COOM (wherein n is an integer of 2 to 28, and M is the same as above).

[0273] The anionic hydrocarbon surfactant may also be, for example, a surfactant represented by the following formula (β): １００ -SO ３ M (β) (wherein, R １００ is a monovalent organic group containing one or more carbon atoms (preferably an organic group not containing fluorine); M is H, a metal atom, NR １０１ ４ , optionally substituted imidazolium, optionally substituted pyridinium, or optionally substituted phosphonium, and R １０１ R is H or an organic group (preferably an organic group not containing fluorine), and may be the same or different. １０１ The organic group in R is preferably an alkyl group. １０１ is preferably H or an organic group having 1 to 10 carbon atoms, more preferably H or an organic group having 1 to 4 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms. １００ The number of carbon atoms in R is preferably 2 or more, and more preferably 3 or more. １００ The number of carbon atoms in is preferably 29 or less, more preferably 23 or less. The metal atom of M includes alkali metals (Group 1) and alkaline earth metals (Group 2), and Na, K, or Li is preferred. M is H, a metal atom, or NR １０１ ４is preferred, and H, an alkali metal (Group 1), an alkaline earth metal (Group 2) or NR １０１ ４ is more preferred, and H, Na, K, Li or NH ４ is more preferred, Na, K or NH ４ is even more preferred, Na or NH ４ is particularly preferred, and NH ４ is most preferred.

[0274] The compound (β) is R １０２ -SO ３ M (wherein, R １０２ is a linear or branched alkyl group, alkenyl group, alkylene group or alkenylene group having 1 or more carbon atoms which may have a substituent, or a cyclic alkyl group, alkenyl group, alkylene group or alkenylene group having 3 or more carbon atoms which may have a substituent, and these may contain an ether bond. When the carbon number is 3 or more, it may contain a monovalent or divalent heterocycle or may form a ring. M is the same as above. ) are also included. Specifically, CH ３ - (CH ２ ) ｎ -SO ３ M (wherein n is an integer of 2 to 28; M is the same as above).

[0275] The anionic hydrocarbon surfactant may be a surfactant represented by the following formula I: R-(XZ) ｎ (I) wherein R is a hydrophobic hydrocarbon moiety containing one or more saturated or unsaturated, acyclic or cyclic aliphatic groups. ３ , C.H. ２ and CH relative to the total of CH groups ３ The total percentage of groups is at least about 70%, and the hydrophobic moiety does not include a siloxane unit. Each X, which may be the same or different, represents an ionic hydrophilic moiety. Each Z, which may be the same or different, represents one or more counterions of the ionic hydrophilic moiety. n is 1 to 3.

[0276] Compound I exhibits low reactivity with polymerization initiators and / or propagating fluoropolymer radicals in emulsion polymerization of fluoromonomers.

[0277] Compound I has the following formula: (In the formula, Y ＋ is hydrogen, ammonium, quaternary ammonium, a nitrogen heterocycle, an alkali metal, or an alkaline earth metal.

[0278] Compound I has the following formula II: (In the formula, R ２’ and R ２’’’ are the same or different and are saturated or unsaturated, acyclic or cyclic aliphatic groups having 4 to 16 carbon atoms; R ２’ and R ２’’’ CH in the group ３ , C.H. ２ and CH relative to the total of CH groups ３ The total percentage of groups is at least about 70%, or R ２’ and R ２’’’ may be bonded to each other to form a saturated or unsaturated aliphatic ring which may contain ether or ester bonds, provided that CH ３ , C.H. ２ and CH relative to the total of CH groups ３ The total percentage of R groups is at least about 70%. １ is hydrogen, methoxy, ethoxy or phenoxy. ＋ is hydrogen, ammonium, quaternary ammonium, a nitrogen heterocycle, an alkali metal, or an alkaline earth metal.

[0279] As Compound II, for example, the following compounds are preferred. Y in the above formula ＋ may be hydrogen, ammonium, or an alkali metal.

[0280] Compound I has the following formula III: (In the formula, R ３ , R ４’ , and R ４’’are the same or different and are hydrogen or a saturated or unsaturated, acyclic or cyclic aliphatic group having 4 to 16 carbon atoms; R ３ , R ４’ , and R ４’’ CH in the group ３ , C.H. ２ and CH relative to the total of CH groups ３ The total percentage of R is at least about 70%. ３ , R ４’ , and R ４’’ At least one of R is not hydrogen; ４’ and R ４’’ is hydrogen, R ３ is not hydrogen, but R ３ is hydrogen, R ４’ and R ４’’ is not hydrogen. ＋ is hydrogen, ammonium, quaternary ammonium, a nitrogen heterocycle, an alkali metal, or an alkaline earth metal.

[0281] As the compound III, for example, the following compounds are preferred. Y in the above formula ＋ may be hydrogen, ammonium, or an alkali metal.

[0282] Even if the TFE polymer composition of the present disclosure does not use the above-mentioned specific hydrocarbon surfactant, it can be obtained by a production method comprising the polymerization step of obtaining TFE polymer by polymerizing only tetrafluoroethylene or tetrafluoroethylene and the modified monomer copolymerizable with the above-mentioned tetrafluoroethylene in an aqueous medium with pH 4.0 or more in the presence of hydrocarbon surfactant and polymerization initiator.Conventionally, the polymerization step for producing TFE polymer has used an acidic polymerization initiator, so the pH of the aqueous medium used in polymerization is less than 4.0.Through intensive research, the present inventors have unexpectedly found that by making the pH of the aqueous medium used for polymerization 4.0 or more, the stability of polymerization can be improved, and the TFE polymer with high molecular weight can be produced.The above-mentioned production method comprises the polymerization of only tetrafluoroethylene or tetrafluoroethylene and the modified monomer copolymerizable with the above-mentioned tetrafluoroethylene in an aqueous medium with pH 4.0 or more. The pH may be 4.0 or higher, preferably greater than 4.0, more preferably 4.5 or higher, even more preferably 5.0 or higher, even more preferably 5.5 or higher, particularly preferably 6.0 or higher, particularly preferably 6.5 or higher, particularly preferably 7.0 or higher, particularly preferably 7.5 or higher, and particularly preferably 8.0 or higher. The upper limit of the pH is not particularly limited, but may be, for example, 13.0 or lower. From the viewpoint of corrosion of the polymerization vessel, it is preferably 12.0 or lower, more preferably 11.5 or lower, and even more preferably 11.0 or lower. The pH can be measured using a pH meter.

[0283] Even if the TFE polymer composition of the present disclosure does not use the specific hydrocarbon surfactant, it can also be obtained by a polymerization step comprising the steps of polymerizing tetrafluoroethylene alone or tetrafluoroethylene and a modified monomer copolymerizable with the tetrafluoroethylene in an aqueous medium in the presence of an anionic hydrocarbon surfactant and a polymerization initiator to obtain a TFE polymer, and the hydrocarbon surfactant comprises a salt of the hydrocarbon surfactant.In other words, at least a part of the anionic hydrocarbon surfactant in the polymerization step is in the form of a salt.Through intensive research, the present inventors have unexpectedly found that the stability of polymerization is improved by the anionic hydrocarbon surfactant comprising a salt of the anionic hydrocarbon surfactant, and a TFE polymer with a large molecular weight can be produced.This is thought to be due to the fact that the anionic surfactant comprises a salt, improving the water solubility of the anionic surfactant, and making it easier to exhibit emulsification performance.The anionic hydrocarbon surfactant will be described later.The fact that the anionic hydrocarbon surfactant comprises a salt of the hydrocarbon surfactant can be confirmed by measuring conductivity. In the above-mentioned production method, the concentration of the salt of the anionic hydrocarbon surfactant is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and particularly preferably 95% by mass or more, relative to the total mass of the anionic hydrocarbon surfactant. The proportion of the salt can be measured by the solution concentration and conductivity. In the above-mentioned production method, the hydrocarbon surfactant is more preferably a carboxylic acid-type hydrocarbon surfactant. The hydrocarbon surfactant does not contain fluorine. In the salt of the anionic hydrocarbon surfactant, the cation (excluding hydrogen atoms) replacing the hydrogen atom of the acid can be, for example, a metal atom, NR ｙ ４ (R ｙmay be the same or different and are H or an organic group (preferably an organic group not containing fluorine)), an imidazolium which may have a substituent, a pyridinium which may have a substituent, or a phosphonium which may have a substituent. ｙ is preferably H or an alkyl group, more preferably H or an alkyl group having 1 to 10 carbon atoms, and even more preferably H or an alkyl group having 1 to 4 carbon atoms. The cation in the salt of the anionic hydrocarbon surfactant may be a metal atom or NR ｙ ４ is preferred, and NR ｙ ４ is more preferred, and NH ４ Since the conductivity is greatly affected by temperature, the temperature of the sample liquid is kept at 25°C using a thermostatic bath, and the temperature of the pH meter cell is also kept at the same temperature before measuring the conductivity.

[0284] The TFE polymer composition of the present disclosure can be suitably produced by a production method comprising the addition step of adding at least one selected from the group consisting of radical scavengers and decomposers of polymerization initiators.The above-mentioned addition step is carried out during the step of carrying out the above-mentioned emulsion polymerization in an aqueous medium.By adding radical scavengers or decomposers of polymerization initiators, the radical concentration during polymerization can be adjusted.From the viewpoint of reducing radical concentration, radical scavengers are preferred.

[0285] The radical scavenger is a compound that does not have the ability to reinitiation after addition or chain transfer to the free radicals in the polymerization system. Specifically, a compound that easily undergoes chain transfer reaction with a primary radical or a propagating radical to generate a stable radical that does not subsequently react with the monomer, or a compound that easily undergoes an addition reaction with a primary radical or a propagating radical to generate a stable radical, is used. The activity of what is generally called a chain transfer agent is characterized by the chain transfer constant and the reinitiation efficiency, and among chain transfer agents, those with a reinitiation efficiency of almost 0% are called radical scavengers. The radical scavenger can also be described as, for example, a compound whose chain transfer constant with TFE at the polymerization temperature is greater than the polymerization rate constant and whose reinitiation efficiency is essentially 0%. "Reinitiation efficiency is essentially 0%" means that the generated radical turns the radical scavenger into a stable radical. Preferably, the compound has a chain transfer constant (Cs) (= chain transfer rate constant (kc) / polymerization rate constant (kp)) with TFE at polymerization temperature of more than 0.1, and the chain transfer constant (Cs) of the compound is more preferably 0.5 or more, even more preferably 1.0 or more, even more preferably 5.0 or more, and particularly preferably 10 or more.

[0286] Examples of the radical scavenger in the present disclosure include aromatic hydroxy compounds, aromatic amines, N,N-diethylhydroxylamine, quinone compounds, terpenes, thiocyanates, and cupric chloride (CuCl ２) is preferred. Examples of aromatic hydroxy compounds include unsubstituted phenol, polyhydric phenol, salicylic acid, m- or p-salicylic acid, gallic acid, naphthol, etc. Examples of unsubstituted phenols include o-, m-, or p-nitrophenol, o-, m-, or p-aminophenol, p-nitrosophenol, etc. Examples of polyhydric phenols include catechol, resorcinol, hydroquinone, pyrogallol, phloroglucinol, naphthresorcinol, etc. Examples of aromatic amines include o-, m-, or p-phenylenediamine, benzidine, etc. Examples of quinone compounds include o-, m-, or p-benzoquinone, 1,4-naphthoquinone, alizarin, etc. Examples of thiocyanates include ammonium thiocyanate (NH ４ Examples of the radical scavenger include potassium thiocyanate (KSCN), sodium thiocyanate (NaSCN), etc. Among these, aromatic hydroxy compounds are preferred, unsubstituted phenols or polyhydric phenols are more preferred, and hydroquinone is even more preferred.

[0287] From the viewpoint of reducing the standard specific gravity, the amount of radical scavenger added is preferably an amount corresponding to 3 to 500% (molar basis) of the polymerization initiator concentration. A more preferred lower limit is 5% (molar basis), even more preferably 8% (molar basis), even more preferably 10% (molar basis), even more preferably 15% (molar basis), especially even more preferably 20% (molar basis), particularly preferably 25% (molar basis), especially preferably 30% (molar basis), especially preferably 35% (molar basis). A more preferred upper limit is 400% (molar basis), even more preferably 300% (molar basis), even more preferably 200% (molar basis), especially even more preferably 100% (molar basis).

[0288] The polymerization initiator decomposer may be any compound capable of decomposing the polymerization initiator used. For example, at least one selected from the group consisting of sulfites, bisulfites, bromates, diimines, diimine salts, oxalic acid, oxalates, copper salts, and iron salts is preferred. Examples of sulfites include sodium sulfite and ammonium sulfite. Examples of copper salts include copper(II) sulfate, and examples of iron salts include iron(II) sulfate. The amount of the polymerization initiator decomposer added is in the range of 25 to 300% by mass relative to the amount of the oxidizing agent combined as the polymerization initiator (the redox initiator described below). This is preferably 25 to 150% by mass, more preferably 50 to 100% by mass. The amount of the polymerization initiator decomposer added is preferably an amount equivalent to 3 to 500% (molar basis) of the polymerization initiator concentration in order to reduce the standard specific gravity. A more preferred lower limit is 5% (molar basis), even more preferably 8% (molar basis), even more preferably 10% (molar basis), even more preferably 13% (molar basis), even more preferably 15% (molar basis).A more preferred upper limit is 400% (molar basis), even more preferably 300% (molar basis), even more preferably 200% (molar basis), and especially preferably 100% (molar basis).

[0289] At least one selected from the group consisting of radical scavengers and decomposers of polymerization initiators is preferably added when the concentration of the TFE-based polymer formed in the aqueous medium is 5% by mass or more, more preferably 10% by mass or more, and is preferably added when the concentration of the TFE-based polymer formed in the aqueous medium is 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less.

[0290] The addition step may be a step of continuously adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator. Continuously adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator means, for example, adding at least one selected from the group consisting of a radical scavenger and a decomposer of a polymerization initiator over time, without interruption, or in portions, rather than all at once.

[0291] The polymerization step may further comprise polymerizing tetrafluoroethylene in the presence of a nucleating agent.

[0292] As the nucleating agent, for example, it is preferred to be at least one selected from the group consisting of fluoropolyether, nonionic surfactant and chain transfer agent.In this case, it is preferred that the polymerization step is the step of obtaining TFE polymer by polymerizing tetrafluoroethylene in aqueous medium under the presence of hydrocarbon surfactant and the nucleating agent.

[0293] The fluoropolyether is preferably a perfluoropolyether.

[0294] The fluoropolyether preferably has repeating units represented by formulas (1a) to (1d): (-CFCF ３ -CF ２ -O-) ｎ (1a) (-CF ２ -CF ２ -CF ２ -O-) ｎ (1b) (-CF ２ -CF ２ -O-) ｎ -(-CF ２ -O-) ｍ (1c) (-CF ２ -CFCF ３ -O-) ｎ -(-CF ２ -O-) ｍ (1d) (In formulas (1a) to (1d), m and n are integers of 1 or more.)

[0295] The fluoropolyether is preferably a fluoropolyether acid or its salt, and the fluoropolyether acid is preferably a carboxylic acid, a sulfonic acid, a sulfonamide, or a phosphonic acid, and more preferably a carboxylic acid. Among the fluoropolyether acids or their salts, the salt of a fluoropolyether acid is preferred, the ammonium salt of a fluoropolyether acid is more preferred, and the ammonium salt of a fluoropolyether carboxylic acid is even more preferred.

[0296] The fluoropolyether acids or salts thereof can have any chain structure in which the oxygen atoms in the backbone of the molecule are separated by saturated fluorocarbon groups having 1 to 3 carbon atoms. More than one type of fluorocarbon group can be present in the molecule.

[0297] The fluoropolyether acid or salt thereof may be a fluoropolyether acid represented by the following formula: CF ３ -CF ２ -CF ２ -O(-CFCF ３ -CF ２ -O-) ｎ CFCF ３ -COOH, CF ３ -CF ２ -CF ２ -O(-CF ２ -CF ２ -CF ２ -O-) ｎ -CF ２ -CF ２ COOH or HOOC-CF ２ -O(-CF ２ -CF ２ -O-) ｎ -(-CF ２ -O-) ｍ CF ２ COOH (wherein m and n are the same as above) or a salt thereof is preferred.

[0298] These structures are discussed by Kasai in J. Appl. Polymer Sci., 57, 797 (1995). As disclosed therein, such fluoropolyethers can have a carboxylic acid group or its salt at one or both ends. Similarly, such fluoropolyethers can have a sulfonic acid or phosphonic acid group or its salt at one or both ends. In addition, fluoropolyethers with acid functional groups at both ends can have different groups at each end. For monofunctional fluoropolyethers, the other end of the molecule is usually perfluorinated, but may contain a hydrogen or chlorine atom.

[0299] Fluoropolyethers having acid groups at one or both ends have at least two ether oxygens, preferably at least four ether oxygens, and even more preferably at least six ether oxygens. Preferably, at least one of the fluorocarbon groups separating the ether oxygens, more preferably at least two of such fluorocarbon groups, has 2 or 3 carbon atoms. Even more preferably, at least 50% of the fluorocarbon groups separating the ether oxygens have 2 or 3 carbon atoms. Also, preferably, the fluoropolyether has a total of at least 15 carbon atoms, and for example, the preferred minimum value of n or n + m in the above repeating unit structure is at least 5. Two or more fluoropolyethers having acid groups at one or both ends can be used in the method according to the present disclosure. Typically, unless special care is taken in the preparation of a single specific fluoropolyether compound, the fluoropolyether may contain multiple compounds in various proportions within the molecular weight range relative to the average molecular weight.

[0300] The fluoropolyether preferably has a number average molecular weight of 800 g / mol or more. Because the fluoropolyether acid or its salt may be difficult to disperse in an aqueous medium, the number average molecular weight is preferably less than 6000 g / mol. The fluoropolyether acid or its salt more preferably has a number average molecular weight of 800 to 3500 g / mol, and even more preferably 1000 to 2500 g / mol.

[0301] The amount of the fluoropolyether is preferably 5 to 3000 ppm, more preferably 5 to 2000 ppm, with a more preferred lower limit of 10 ppm and a more preferred upper limit of 100 ppm relative to the aqueous medium.

[0302] Examples of the nonionic surfactant as the nucleating agent include the nonionic surfactants described above, and preferably nonionic surfactants that do not contain fluorine. For example, the nonionic surfactant may be a nonionic surfactant represented by the following general formula (i): ３ -O-A １ -H (i) (wherein, R３ is a linear or branched primary or secondary alkyl group having 8 to 18 carbon atoms, and A １ is a polyoxyalkylene chain. ３ The number of carbon atoms in R is preferably 10 to 16, and more preferably 12 to 16. ３ When the carbon number of R is 18 or less, good dispersion stability of the aqueous dispersion is easily obtained. ３ If the carbon number of R exceeds 18, the flow temperature is high and it is difficult to handle. ３ If the number of carbon atoms is less than 8, the surface tension of the aqueous dispersion increases, and the permeability and wettability tend to decrease.

[0303] The polyoxyalkylene chain may be composed of oxyethylene and oxypropylene. It is a polyoxyalkylene chain having an average repeat number of 5 to 20 oxyethylene groups and an average repeat number of 0 to 2 oxypropylene groups, and is a hydrophilic group. The number of oxyethylene units may include either a broad or narrow unimodal distribution as is usually provided, or a broader or bimodal distribution obtained by blending. When the average repeat number of oxypropylene groups is greater than 0, the oxyethylene groups and oxypropylene groups in the polyoxyalkylene chain may be arranged in a block or random configuration. From the viewpoint of viscosity and stability of the aqueous dispersion, a polyoxyalkylene chain having an average repeat number of 7 to 12 oxyethylene groups and an average repeat number of 0 to 2 oxypropylene groups is preferred. In particular, A １ When the number of oxypropylene groups is 0.5 to 1.5 on average, low foaming properties are favorable, and this is preferred.

[0304] More preferably, R ３ is (R')(R'')HC-, where R' and R'' are the same or different straight, branched, or cyclic alkyl groups having a total of at least 5, preferably 7 to 17, carbon atoms. Preferably, at least one of R' or R'' is a branched or cyclic hydrocarbon group.

[0305] Specific examples of the polyoxyethylene alkyl ether include C １３ H ２７-O-(C ２ H ４ O) １０ -H, C １２ H ２５ -O-(C ２ H ４ O) １０ -H, C １０ H ２１ CH (CH ３ ) CH ２ -O-(C ２ H ４ O) ９ -H, C １３ H ２７ -O-(C ２ H ４ O) ９ -(CH(CH ３ ) CH ２ O) -H,C １６ H ３３ -O-(C ２ H ４ O) １０ -H, HC(C ５ H １１ ) (C ７ H １５ )—O—(C ２ H ４ O) ９ -H, etc. Examples of commercially available polyoxyethylene alkyl ethers include Genapol X080 (product name, manufactured by Clariant), the Noigen TDS series (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) such as Noigen TDS-80 (trade name), the Leocol TD series (manufactured by Lion Corporation) such as Leocol TD-90 (trade name), the Lionol (registered trademark) TD series (manufactured by Lion Corporation), the T-Det A series (manufactured by Harcros Chemicals) such as T-Det A138 (trade name), and the Tergitol (registered trademark) 15S series (manufactured by Dow).

[0306] Also preferred is an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 4 to about 18 ethylene oxide units, an ethoxylate of 2,6,8-trimethyl-4-nonanol having an average of about 6 to about 12 ethylene oxide units, or a mixture thereof. Nonionic surfactants of this type are also commercially available, for example, under the trade names TERGITOL TMN-6, TERGITOL TMN-10, and TERGITOL TMN-100X (all manufactured by The Dow Chemical Company).

[0307] The hydrophobic group of the nonionic surfactant may be any of an alkylphenol group, a linear alkyl group, and a branched alkyl group. For example, a polyoxyethylene alkylphenyl ether-based nonionic compound may be, for example, a compound represented by the following general formula (ii): ４ -C ６ H ４ -O-A ２ -H (ii) (wherein, R ４ is a linear or branched primary or secondary alkyl group having 4 to 12 carbon atoms, A ２ is a polyoxyalkylene chain. Specific examples of the polyoxyethylene alkylphenyl ether-based nonionic compounds include Triton (registered trademark) X-100 (product name, manufactured by Dow Chemical Company).

[0308] Other nonionic surfactants include difunctional block copolymers supplied by BASF as their Pluronic® R series, tridecyl alcohol alkoxylates supplied by BASF Corporation as their Iconol® TDA series, hydrocarbon-containing siloxane surfactants, preferably hydrocarbon surfactants, wherein the hydrocarbyl groups, which may be substituted by halogens such as fluorine, are fully substituted by hydrogen atoms, whereby these siloxane surfactants can also be considered hydrocarbon surfactants, i.e., the monovalent substituents on the hydrocarbyl groups are hydrogen.

[0309] In the above production method, in addition to the specific hydrocarbon surfactant and other surface-active compounds used as desired, additives can be used to stabilize each compound, such as buffers, pH adjusters, stabilizing aids, and dispersion stabilizers.

[0310] Preferred stabilizing aids include paraffin wax, fluorine-based oil, fluorine-based solvent, and silicone oil. The stabilizing aids may be used alone or in combination of two or more. Paraffin wax is more preferred as the stabilizing aid. Paraffin wax may be liquid, semi-solid, or solid at room temperature, but saturated hydrocarbons having 12 or more carbon atoms are preferred. The melting point of the paraffin wax is generally preferably 40 to 65°C, more preferably 50 to 65°C.

[0311] The amount of the stabilizing aid used is preferably 0.1 to 12% by mass, more preferably 0.1 to 8% by mass, based on the mass of the aqueous medium used. It is desirable that the stabilizing aid is sufficiently hydrophobic so that it is completely separated from the aqueous TFE polymer emulsion after emulsion polymerization of TFE and does not become a contaminating component.

[0312] In the above production method, emulsion polymerization can be carried out by charging an aqueous medium, the hydrocarbon surfactant, monomers, and other additives as necessary into a polymerization reactor, stirring the contents of the reactor, maintaining the reactor at a predetermined polymerization temperature, and then adding a predetermined amount of polymerization initiator to initiate the polymerization reaction. After the polymerization reaction has started, additional monomers, polymerization initiators, chain transfer agents, the surfactants, etc. may be added depending on the purpose. The hydrocarbon surfactant may also be added after the polymerization reaction has started.

[0313] In the emulsion polymerization, the polymerization temperature and polymerization pressure are appropriately determined depending on the type of monomer used, the molecular weight of the target TFE-based polymer, and the reaction rate. Usually, the polymerization temperature is 5 to 150 ° C, preferably 10 ° C or higher, more preferably 30 ° C or higher, and even more preferably 50 ° C or higher. Also, it is more preferably 120 ° C or lower, and even more preferably 100 ° C or lower. The polymerization pressure is 0.05 to 10 MPaG. The polymerization pressure is more preferably 0.3 MPaG or higher, and even more preferably 0.5 MPaG or higher. Also, it is more preferably 5.0 MPaG or lower, and even more preferably 3.0 MPaG or lower. In particular, from the viewpoint of improving the yield, it is preferably 1.0 MPaG or higher, more preferably 1.2 MPaG or higher, more preferably 1.5 MPaG or higher, even more preferably 1.8 MPaG or higher, and particularly preferably 2.0 MPaG or higher.

[0314] In the emulsion polymerization, the hydrocarbon surfactant is preferably added when the concentration of the TFE polymer formed in the aqueous medium is less than 0.60 mass%.More preferably, the concentration is 0.50 mass% or less, even more preferably 0.36 mass% or less, even more preferably 0.30 mass% or less, particularly preferably 0.20 mass% or less, and particularly preferably 0.10 mass% or less, and most preferably added at the start of polymerization.The above concentration is the concentration relative to the total of the aqueous medium and the TFE polymer.In addition, in the emulsion polymerization, the amount of the hydrocarbon surfactant at the start of polymerization is preferably 1 ppm or more relative to the aqueous medium.The amount of the hydrocarbon surfactant at the start of polymerization is preferably 10 ppm or more, more preferably 50 ppm or more, even more preferably 100 ppm or more, and even more preferably 200 ppm or more.The upper limit is not particularly limited, but for example, it is preferably 100,000 ppm, and more preferably 50,000 ppm. By setting the amount of hydrocarbon surfactant at the start of polymerization within the above range, an aqueous dispersion having a smaller average primary particle size and better stability can be obtained.

[0315] The polymerization initiator is not particularly limited as long as it can generate radicals in the above-mentioned polymerization temperature range, and can use known oil-soluble and / or water-soluble polymerization initiator.Furthermore, it can also be combined with reducing agent etc. to initiate polymerization as redox.The concentration of the polymerization initiator is suitably determined according to the type of monomer, the molecular weight of the target TFE polymer and reaction rate.

[0316] As the polymerization initiator, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used.

[0317] The oil-soluble radical polymerization initiator may be a known oil-soluble peroxide, and representative examples thereof include dialkyl peroxycarbonates such as diisopropyl peroxydicarbonate and disec-butyl peroxydicarbonate, peroxyesters such as t-butyl peroxyisobutyrate and t-butyl peroxypivalate, and dialkyl peroxides such as di-t-butyl peroxide.

[0318] The water-soluble radical polymerization initiator may be a known water-soluble peroxide, such as ammonium salts, potassium salts, or sodium salts of persulfuric acid, perborate, perchloric acid, perphosphoric acid, or percarbonate, t-butyl permaleate, or t-butyl hydroperoxide. A reducing agent such as a sulfite or sulfite may also be contained, and the amount used may be 0.1 to 20 times the amount of the peroxide.

[0319] For example, when polymerization is carried out at a low temperature of 30°C or less, it is preferable to use a redox initiator that combines an oxidizing agent and a reducing agent as the polymerization initiator. Examples of oxidizing agents include persulfates, organic peroxides, potassium permanganate, manganese triacetate, cerium ammonium nitrate, and bromates. Examples of reducing agents include sulfites, bisulfites, bromates, diimines, and oxalic acid. Examples of persulfates include ammonium persulfate and potassium persulfate. Examples of sulfites include sodium sulfite and ammonium sulfite. In order to increase the decomposition rate of the initiator, it is also preferable to add a copper salt or an iron salt to the redox initiator combination. Examples of copper salts include copper(II) sulfate, and examples of iron salts include iron(II) sulfate.

[0320] The redox initiator preferably has an oxidizing agent that is permanganic acid or a salt thereof, a persulfate, manganese triacetate, a cerium (IV) salt, or a bromic acid or a salt thereof, and a reducing agent that is a dicarboxylic acid or a salt thereof, or a diimine. More preferably, the oxidizing agent is permanganic acid or a salt thereof, a persulfate, or a bromic acid or a salt thereof, and the reducing agent is a dicarboxylic acid or a salt thereof.

[0321] Examples of the redox initiator include combinations such as potassium permanganate / oxalic acid, potassium permanganate / ammonium oxalate, manganese triacetate / oxalic acid, manganese triacetate / ammonium oxalate, cerium ammonium nitrate / oxalic acid, and cerium ammonium nitrate / ammonium oxalate. When using a redox initiator, either an oxidizing agent or a reducing agent may be charged into a polymerization vessel in advance, followed by continuous or intermittent addition of the other agent to initiate polymerization. For example, when potassium permanganate / ammonium oxalate is used, it is preferable to charge ammonium oxalate into a polymerization vessel and then continuously add potassium permanganate thereto. Note that, in this specification, the term "potassium permanganate / ammonium oxalate" refers to a combination of potassium permanganate and ammonium oxalate. The same applies to other compounds. As the redox initiator, it is preferable to use an oxidizing agent or reducing agent capable of adjusting the pH of the redox initiator aqueous solution to 4.0 or higher. The redox initiator aqueous solution refers to a 0.50% by mass aqueous solution of an oxidizing agent or a 0.50% by mass aqueous solution of a reducing agent. That is, it is sufficient that the pH of at least one of the 0.50% by mass aqueous solution of an oxidizing agent and the 0.50% by mass aqueous solution of a reducing agent is 4.0 or higher, and it is preferable that the pH of both the 0.50% by mass aqueous solution of an oxidizing agent and the 0.50% by mass aqueous solution of a reducing agent is 4.0 or higher. The pH of the redox initiator aqueous solution (the 0.50% by mass aqueous solution of an oxidizing agent or the 0.50% by mass aqueous solution of a reducing agent) is more preferably 5.0 or higher, even more preferably 5.5 or higher, and particularly preferably 6.0 or higher.

[0322] The redox initiator is preferably a combination of an oxidizing agent that is a salt and a reducing agent that is a salt. For example, the oxidizing agent that is a salt is more preferably at least one selected from the group consisting of persulfates, permanganates, cerium (IV) salts, and bromates, more preferably permanganates, and particularly preferably potassium permanganate. The reducing agent that is a salt is more preferably at least one selected from the group consisting of oxalates, malonates, succinates, glutarates, and bromates, more preferably oxalates, and particularly preferably ammonium oxalate.

[0323] Specifically, the redox initiator is preferably at least one selected from the group consisting of potassium permanganate / ammonium oxalate, potassium bromate / ammonium sulfite, manganese triacetate / ammonium oxalate, and cerium ammonium nitrate / ammonium oxalate, and more preferably at least one selected from the group consisting of potassium permanganate / ammonium oxalate, potassium bromate / ammonium sulfite, and cerium ammonium nitrate / ammonium oxalate.

[0324] By using a redox initiator in the polymerization step, the molecular weight of the resulting TFE-based polymer can be increased. Therefore, the SSG can be reduced, making the polymer stretchable. Furthermore, by using a redox initiator in the polymerization step, the number of TFE-based polymer particles produced in the aqueous dispersion can be increased. Furthermore, the yield of the TFE-based polymer can be increased. When a redox initiator is used, the oxidizing agent and the reducing agent may be added all at once at the beginning of polymerization, or the reducing agent may be added all at once at the beginning of polymerization and the oxidizing agent may be added continuously, or the oxidizing agent may be added all at once at the beginning of polymerization and the reducing agent may be added continuously, or both the oxidizing agent and the reducing agent may be added continuously. When a redox initiator is used as a polymerization initiator, the amount of the oxidizing agent added is preferably 5 to 10,000 ppm, more preferably 10 to 1,000 ppm, relative to the aqueous medium, and the amount of the reducing agent added is preferably 5 to 10,000 ppm, more preferably 10 to 1,000 ppm. When a redox initiator is used in the polymerization step, the polymerization temperature is preferably 100° C. or lower, more preferably 95° C. or lower, and even more preferably 90° C. or lower. The polymerization temperature is preferably 10° C. or higher, more preferably 20° C. or higher, and even more preferably 30° C. or higher.

[0325] The amount of polymerization initiator added is not particularly limited, but may be added all at once, stepwise, or continuously at the beginning of polymerization in an amount (for example, several ppm relative to the water concentration) that does not significantly reduce the polymerization rate. The upper limit is a range in which the reaction temperature can be increased while removing heat from the equipment using the heat of polymerization reaction, and a more preferred upper limit is a range in which the heat of polymerization reaction can be removed from the equipment. More specifically, for example, the amount is preferably 1 ppm or more relative to the aqueous medium, more preferably 10 ppm or more, and even more preferably 50 ppm or more. Also, the amount is preferably 100,000 ppm or less, more preferably 10,000 ppm or less, and even more preferably 5,000 ppm or less.

[0326] The aqueous medium is a reaction medium for polymerization and refers to a liquid containing water. The aqueous medium is not particularly limited as long as it contains water, and may contain water and, for example, a fluorine-free organic solvent such as an alcohol, an ether, or a ketone, and / or a fluorine-containing organic solvent having a boiling point of 40° C. or lower.

[0327] In the emulsion polymerization, a known chain transfer agent may be added depending on the purpose to adjust the polymerization rate and molecular weight.

[0328] Examples of the chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate, and dimethyl succinate, as well as isopentane, methane, ethane, propane, isobutane, methanol, ethanol, isopropanol, acetone, various mercaptans, various halogenated hydrocarbons such as carbon tetrachloride, and cyclohexane.

[0329] Bromine compounds or iodine compounds may be used as chain transfer agents. The polymerization method using a bromine compound or an iodine compound may, for example, be a method of polymerizing a fluoromonomer in an aqueous medium in the presence of a bromine compound or an iodine compound in a substantially oxygen-free state (iodine transfer polymerization method). Representative examples of the bromine compound or iodine compound to be used include, for example, compounds represented by the general formula: R ａ I ｘ Br ｙ (wherein x and y are each an integer of 0 to 2 and satisfy 1≦x+y≦2; R ａ is a saturated or unsaturated fluorohydrocarbon group or chlorofluorohydrocarbon group having 1 to 16 carbon atoms, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a crosslinking point.

[0330] Examples of iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo-n-propane, CF ２ Br ２ , BrCF ２ CF ２ Br, CF ３ CFBrCF ２ Br, CFClBr ２ , BrCF ２ CFClBr, CFBrClCFClBr, BrCF ２ CF ２ CF ２ Br, BrCF ２ CFBrOCF ３ , 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo-substituted benzene, diiodomonobromo-substituted benzene, and (2-iodoethyl) and (2-bromoethyl) substituted benzenes, and these compounds may be used alone or in combination with each other.

[0331] Among these, it is preferable to use 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane in terms of polymerization reactivity, crosslinking reactivity, availability, and the like.

[0332] The amount of the chain transfer agent used is usually 1 to 50,000 ppm, preferably 1 to 20,000 ppm, based on the total amount of fluoromonomers supplied.

[0333] The chain transfer agent may be added all at once to the reaction vessel before the initiation of polymerization, may be added all at once after the initiation of polymerization, may be added in multiple divided portions during the polymerization, or may be added continuously during the polymerization.

[0334] An aqueous dispersion of a TFE-based polymer can be obtained by the emulsion polymerization. The aqueous dispersion usually contains a TFE-based polymer, compound (1) and / or (2), and an aqueous medium. The solids concentration of the aqueous dispersion is not limited, but may be, for example, 1.0 to 70% by mass. The solids concentration is preferably 8.0% by mass or more, more preferably 10.0% by mass or more, and preferably 60.0% by mass or less, more preferably 50.0% by mass or less. In the production method, the adhesion amount is preferably 3.0% by mass or less, more preferably 2.0% by mass or less, more preferably 1.0% by mass or less, even more preferably 0.8% by mass or less, even more preferably 0.7% by mass or less, and particularly preferably 0.6% by mass or less, based on the TFE-based polymer finally obtained.

[0335] The coagulation in step (B) can be carried out by a known method. When coagulating an aqueous dispersion of a TFE-based polymer, the aqueous dispersion obtained by polymerization of a polymer latex or the like is usually diluted with water to a polymer concentration of 10 to 25% by mass (preferably a polymer concentration of 10 to 20% by mass), and in some cases, the pH is adjusted to neutral or alkaline, and then the mixture is stirred more vigorously than during the reaction in a vessel equipped with a stirrer. The coagulation may be carried out while stirring while adding a water-soluble organic compound such as methanol or acetone, an inorganic salt such as potassium nitrate or ammonium carbonate, or an inorganic acid such as hydrochloric acid, sulfuric acid, or nitric acid as a coagulant. The coagulation may also be carried out continuously using an in-line mixer or the like.

[0336] The drying (heat treatment) in step (C) is usually carried out by means of vacuum, high frequency, hot air, or the like, while keeping the wet powder in a state where it is not fluidized much, preferably in a static state. Friction between powders, especially at high temperatures, generally has an undesirable effect on fine powder fibrillating resins. This is because particles made of this type of fibrillating resin tend to easily fibrillate even with a small shear force, losing their original stable particle structure.

[0337] The drying temperature in step (C) is preferably 130° C. or higher, more preferably 140° C. or higher, even more preferably 150° C. or higher, even more preferably 160° C. or higher, even more preferably 180° C. or higher, even more preferably 200° C. or higher, particularly preferably 220° C. or higher, and is preferably 300° C. or lower, more preferably 280° C. or lower, and even more preferably 250° C. or lower, from the viewpoint of more efficiently removing moisture and fluorine-containing compounds.

[0338] The drying time in step (C) is preferably 2 hours or more, more preferably 5 hours or more, even more preferably 10 hours or more, and even more preferably 15 hours or more, from the viewpoint of more efficiently removing moisture and the fluorine-containing compound. The upper limit is not particularly limited, but is, for example, preferably 100 hours, more preferably 50 hours, and even more preferably 30 hours.

[0339] The air velocity in step (C) is preferably 0.01 m / s or more, more preferably 0.03 m / s or more, even more preferably 0.05 m / s or more, and even more preferably 0.1 m / s or more, from the viewpoint of more efficiently removing moisture and fluorine-containing compounds, and is preferably 50 m / s or less, more preferably 30 m / s or less, and even more preferably 10 m / s or less, from the viewpoint of suppressing scattering of powder.

[0340] The drying in step (C) can be carried out using an electric furnace or a steam furnace. For example, it can be carried out using an electric furnace such as a parallel-flow box-type electric furnace, a ventilated box-type electric furnace, a ventilated conveyor-type electric furnace, a band furnace, a radiant conveyor-type electric furnace, a fluidized-bed electric furnace, a vacuum electric furnace, an agitator-type electric furnace, an airflow-type electric furnace, or a hot-air circulation electric furnace, or a steam furnace corresponding to the above (an apparatus obtained by replacing the electric furnace in the apparatus name of each of the above electric furnaces with a steam furnace). In terms of being able to remove moisture and fluorine-containing compounds more efficiently, a parallel-flow box-type electric furnace, a ventilated box-type electric furnace, a ventilated conveyor-type electric furnace, a band furnace, a fluidized-bed electric furnace, a hot-air circulation electric furnace, or a steam furnace corresponding to the above (an apparatus obtained by replacing the electric furnace in the apparatus name of each of the above electric furnaces with a steam furnace) is preferred.

[0341] The drying in step (C) is preferably carried out by placing the wet powder in a container whose bottom and / or sides are breathable, since this allows for more efficient removal of moisture and fluorine-containing compounds. The container whose bottom and / or sides are breathable may be any container that can withstand the drying temperature, but is preferably made of a metal such as stainless steel. As the container whose bottom and / or sides are breathable, a tray (bath) whose bottom and / or sides are breathable is preferred, and a tray whose bottom and / or sides are made of mesh (mesh tray) is more preferred. The mesh is preferably either a woven mesh or a punched metal. The mesh opening is preferably 2000 μm or less (ASTM standard 10 mesh or more), more preferably 595 μm or less (30 mesh or more), even more preferably 297 μm or less (50 mesh or more), even more preferably 177 μm or less (80 mesh or more), particularly preferably 149 μm or less (100 mesh or more), and particularly preferably 74 μm or less (200 mesh or more). Furthermore, it is preferably 25 μm or more (500 mesh or less). When the mesh is a woven net, the weaving method may be, for example, plain weave, twill weave, plain dutch weave, or twill dutch weave. When the mesh is a punched metal, the opening rate is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more. Furthermore, it is preferably 95% or less.

[0342] In the step (C), the amount of the wet powder to be placed is 10 g / cm from the viewpoint of more efficiently removing moisture and fluorine-containing compounds. ２ Preferably, it is 8 g / cm or less. ２ More preferably, it is 5 g / cm or less. ２ More preferably, it is 3 g / cm or less. ２ It is particularly preferable that the density is 0.01 g / cm or less. ２ It is preferable that the density is 0.05 g / cm or more. ２ More preferably, it is 0.1 g / cm or more. ２ More preferably, it is equal to or greater than this.

[0343] The moisture content of the wet powder to be dried in step (C) is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, relative to the wet powder, in order to more efficiently remove moisture and the fluorine-containing compound, and is preferably 150% by mass or less, and more preferably 100% by mass or less.

[0344] The composition of the present disclosure can be suitably used as a binder for electrochemical devices. In particular, it can be suitably used as a binder for batteries, and particularly suitably used as a binder for secondary batteries such as lithium ion batteries. It is particularly preferably used as a binder for lithium ion secondary batteries. The composition of the present disclosure may be used to prepare electrochemical device components, preferably battery components. The composition of the present disclosure can be particularly suitably used as a binder for electrodes. It is preferably used as a binder for positive electrodes, since it can further improve the initial capacity and capacity retention rate of electrochemical devices. The composition of the present disclosure can also be suitably used as a binder in the solid electrolyte layer of a solid secondary battery.

[0345] The present disclosure also provides an electrode mixture containing the composition of the present disclosure and an electrode active material. The use of the electrode mixture of the present disclosure can improve the initial capacity and capacity retention rate of an electrochemical device. Furthermore, because the electrode active material can be held in place even with a small amount of binder, it is possible to add more materials that improve the electrochemical device characteristics, such as active materials and conductive additives.

[0346] As the electrode active material in the electrode mixture of the present disclosure, those described in the electrochemical device of the present disclosure can be used.

[0347] The electrode mixture of the present disclosure may be either a negative electrode mixture or a positive electrode mixture, but is preferably a positive electrode mixture in that it can further improve the initial capacity and capacity retention rate of the electrochemical device.

[0348] The electrode mixture of the present disclosure can be suitably used as an electrode mixture for secondary batteries. In particular, the electrode mixture of the present disclosure is suitable for lithium ion secondary batteries. When used in secondary batteries, the electrode mixture of the present disclosure is usually used in the form of a sheet. The electrode mixture of the present disclosure is preferably in the form of a sheet.

[0349] The thickness of the sheet (electrode mixture sheet) is preferably 300 μm or less, more preferably 250 μm or less, even more preferably 200 μm or less, even more preferably 180 μm or less, particularly preferably 150 μm or less, and is preferably 10 μm or more, more preferably 15 μm or more, and even more preferably 20 μm or more.

[0350] The present disclosure also provides an electrode comprising the composition of the present disclosure, an electrode active material, and a current collector. The electrode of the present disclosure can improve the initial capacity and capacity retention of an electrochemical device. Furthermore, because the electrode active material can be held in place even with a small amount of binder, it is possible to add more materials that improve the electrochemical device characteristics, such as active materials and conductive additives.

[0351] The electrode of the present disclosure may include the above-described electrode mixture (preferably an electrode mixture sheet) of the present disclosure and a current collector.

[0352] The electrodes of the present disclosure are preferably manufactured by a dry process.

[0353] The electrode of the present disclosure may be either a positive electrode or a negative electrode, but is preferably a positive electrode in that it can further improve the initial capacity and capacity retention rate of the electrochemical device.

[0354] The present disclosure also provides a secondary battery comprising the electrode mixture of the present disclosure and a current collector. The secondary battery of the present disclosure has excellent initial capacity and capacity retention. Specific configurations of the secondary battery can be those described for the electrochemical device of the present disclosure.

[0355] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

[0356] The present disclosure will now be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0357] Various physical properties were measured by the following methods.

[0358] <Average primary particle size> Measured by dynamic light scattering. An aqueous fluoropolymer dispersion adjusted to a fluoropolymer solids concentration of approximately 1.0% by mass was prepared, and measurements were taken at 25°C using an ELSZ-1000S (manufactured by Otsuka Electronics Co., Ltd.) for a total of 70 measurements. The refractive index of the solvent (water) was 1.3328, and the viscosity of the solvent (water) was 0.8878 mPa s.

[0359] <Polymer solid content concentration> 1 g of the aqueous polymer dispersion was dried in a blower dryer at 150°C for 60 minutes, and the ratio of the mass of the heating residue to the mass (1 g) of the aqueous dispersion was expressed as a percentage and used as the solid content concentration.

[0360] <Endothermic Peak Temperature> A composition that had not been heated to a temperature of 300° C. or higher was subjected to differential scanning calorimetry (DSC) at a heating rate of 10° C. / min, and the temperature corresponding to the minimum point in the heat of fusion curve was taken as the endothermic peak temperature. When there were two or more minimum points in one melting peak, each of them was taken as the endothermic peak temperature.

[0361] <Standard Specific Gravity (SSG)> Using a sample molded in accordance with ASTM D4895 89, the standard specific gravity was measured by the water displacement method in accordance with ASTM D 792.

[0362] <Liquid Amount> The mass of the composition was measured before and after vacuum heating at 100°C for 5 hours, and the mass was calculated according to the following formula. Three samples were taken, and the mass was calculated for each sample, and the average value was calculated and used. Liquid Amount (mass %) = [(mass (g) of composition before heating) - (mass (g) of composition after heating)] / (mass (g) of composition before heating) x 100

[0363] <Moisture content> Approximately 20 g of the composition was heated at 150°C for 2 hours, and the mass was measured before and after, and calculated according to the following formula. A sample was taken three times, and the mass was calculated for each, and the average value was calculated and adopted. Moisture content (mass %) = [(mass (g) of composition before heating) - (mass (g) of composition after heating)] / (mass (g) of composition before heating) x 100

[0364] Synthesis Example 1 A white solid A was obtained by the method described in Synthesis Example 1 of WO 2021 / 045228.

[0365] Production Example 1 A 6-liter SUS reactor equipped with a SUS stirring blade and a temperature-controlling jacket was charged with 3,480 g of deionized water, 100 g of paraffin wax, and 5.3 g of the white solid A obtained in Synthesis Example 1. The reactor was heated to 70 ° C. while the atmosphere inside the reactor was replaced with nitrogen gas to remove oxygen. TFE was injected to adjust the system pressure to 0.78 MPaG, and the system temperature was maintained at 70 ° C. while stirring. Next, an aqueous solution containing 15.0 mg of ammonium persulfate dissolved in 20 g of water was injected with TFE to initiate the polymerization reaction. As the polymerization reaction progressed, the system pressure decreased, but TFE was added to maintain the system temperature at 70 ° C. and the system pressure at 0.78 MPaG. When 400 g of TFE had been consumed from the start of polymerization, an aqueous solution containing 18.0 mg of hydroquinone dissolved in 20 g of water as a radical scavenger was injected with TFE. The polymerization continued thereafter, and when the polymerization amount of TFE reached approximately 1,200 g from the start of polymerization, stirring and the supply of TFE were stopped. The gas in the system was immediately released to normal pressure, and the polymerization reaction was terminated. The aqueous dispersion was removed and cooled, and the paraffin wax was separated to obtain a PTFE aqueous dispersion. The resulting PTFE aqueous dispersion had an average primary particle size of 310 nm and a solids concentration of 25.3% by mass. The resulting PTFE aqueous dispersion was diluted with deionized water to a solids concentration of 13% by mass, vigorously stirred in a container equipped with a stirrer, and coagulated. The water was then filtered to obtain a wet powder. The resulting wet powder was placed on a stainless steel mesh tray and dried at 210 ° C for 18 hours to obtain PTFE powder X. The resulting PTFE powder X had a moisture content of 0.000% by mass, a standard specific gravity of 2.156, a thermal instability index of 0, an endothermic peak temperature of 343 ° C, and a liquid amount of less than 1% by mass.

[0366] Preparation Example 1: 0.273 g of lauric acid was added to 16 g of deionized water, and 2.77 g of a 2.8% aqueous solution of ammonia was gradually added while stirring to obtain aqueous solution C. 10 g of lauric acid was added to 100 g of deionized water, and 25 g of a 10% aqueous solution of ammonia was gradually added while stirring to obtain aqueous solution D. The pH at this time was 9.6.

[0367] Production Example 2: 1748 g of deionized water, 90 g of paraffin wax, the aqueous solution C obtained in Preparation Example 1, and 0.5 g of ammonium oxalate were added to a 3 L stainless steel reactor equipped with a stirrer. The pH of the aqueous dispersion at this time was 9.0. The reactor was sealed, and the system was purged with nitrogen to remove oxygen. The reactor was heated to 70°C, 2.0 g of HFP was added, and the pressure was increased to 2.70 MPa with TFE. When a 0.5% by mass aqueous potassium permanganate solution was continuously charged into the reactor as a polymerization initiator, a decrease in pressure occurred, and the reaction began. TFE was charged so that the reaction pressure was constant at 2.70 MPa. When 80 g of TFE was charged, stirring was stopped, and the reaction pressure was reduced to atmospheric pressure. Immediately, the reactor was filled with TFE, the reaction pressure was set to 2.70 MPa, stirring was resumed, and the reaction was continued. At the same time, the aqueous solution D obtained in Preparation Example 1 was continuously charged into the reactor. When 680 g of TFE was charged, stirring was stopped, and the reactor was depressurized to atmospheric pressure. By the end of the reaction, 56.0 g of an aqueous potassium permanganate solution and 26.2 g of aqueous solution D were charged. The aqueous dispersion was taken out of the reactor, cooled, and then the paraffin wax was separated to obtain a TFE-based polymer aqueous dispersion. The pH of the obtained TFE-based polymer aqueous dispersion was 8.8, the solid content was 27.1 mass%, and the primary particle size was 220 nm.

[0368] The obtained TFE-based polymer aqueous dispersion is diluted with deionized water to a solid content concentration of 13% by mass, and is vigorously stirred in a container equipped with a stirrer to solidify, and then filtered out from the water to obtain wet powder.The obtained wet powder is placed on a stainless steel mesh tray, and dried at 210 ° C for 18 hours to obtain TFE-based polymer powder 1.The obtained TFE-based polymer powder 1 has a water content of 0.002% by mass, a standard specific gravity of 2.170, a thermal instability index of 44, an HFP content of 0.002% by mass, a 0.1% by mass reduction temperature of 391 ° C, a 1.0% by mass reduction temperature of 491 ° C, and an endothermic peak temperature of 342 ° C.

[0369] Preparation Example 1 The PTFE powder X obtained in Preparation Example 1 and the Li replenisher (Li ５ FeO ４) were mixed in a mass ratio of 2:3 and placed in a V-type mixer (VK-1, manufactured by Irie Shokai Co., Ltd.), where they were mixed at 30 rpm for 10 minutes. The mixture obtained after mixing was designated Composition A. The amount of liquid in Composition A was less than 1 mass %.

[0370] Preparation Example 2 The TFE-based polymer powder 1 obtained in Preparation Example 2 and the Li replenisher (Li ５ FeO ４ ) were mixed in a mass ratio of 2:3, and the mixture was placed in a V-type mixer (VK-1, manufactured by Irie Shokai Co., Ltd.) and mixed at 30 rpm for 10 minutes. The mixture obtained after mixing was designated Composition B. The amount of liquid in Composition B was less than 1 mass %.

[0371] Evaluation of Electrolyte-Containing Batteries Batteries of Examples A1 to A6 and Comparative Example A1 were produced and evaluated according to the following procedures.

[0372] <Preparation of Positive Electrode Mixture Sheet> (Examples A1 to A4) The active material and conductive additive were weighed, and the materials were added to a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture of the active material and conductive additive. Then, the weighed binder (PTFE powder X) and Li supplement were added to the mixture and thoroughly cooled in a 5 ° C. thermostatic bath. The mixture of the active material, conductive additive, Li supplement, and binder was added to a 1 L-scale Henschel mixer and homogenized by processing at 1000 rpm for 3 minutes. The mixture was then thoroughly heated in a 50 ° C. thermostatic bath and then processed in a Henschel mixer at 3000 rpm for 50 minutes to promote fibrillation, and an electrode mixture was obtained. The positive electrode mixture was placed between metal rolls arranged in parallel on the left and right and rolled to obtain a positive electrode mixture sheet (left and right roll temperature: 100°C, left roll rotation speed: 1 m / min, right roll rotation speed: 0.4 m / min). A total of 1000 g was placed into the Henschel mixer. Table 1 shows the material types and compositions.

[0373] (Example A5) The active material and conductive additive were weighed, added to a V-type mixer, and mixed at 37 rpm for 10 minutes to obtain a mixture of the active material and conductive additive. The weighed binder (Composition A) was then added to the mixture, and the mixture was thoroughly cooled in a thermostatic chamber at 5°C. Subsequently, an electrode mixture sheet was obtained using the same procedures as in Examples A1 to A4. Table 1 shows the material types and compositions.

[0374] Example A6 An electrode mixture sheet was obtained in the same manner as in Example A5, except that composition B was used as the binder instead of composition A. Table 1 shows the material types and compositions.

[0375] (Comparative Example A1) The active material and conductive additive were weighed, added to a V-type mixer, and mixed at 37 rpm for 10 minutes to obtain a mixture of the active material and conductive additive. The weighed binder (PTFE powder X) was then added to the mixture, and the mixture was thoroughly cooled in a constant temperature bath at 5°C without adding any Li supplement. A positive electrode mixture sheet was then obtained using the same procedure as in Examples A1 to A4. Table 1 shows the material types and compositions.

[0376] NMC811 is Li (Ni ０．８ Mn ０．１ Co ０．１ ) O ２ SuperP Li represents carbon black manufactured by Imerys. Li ５ FeO ４ Commercially available products were used. ２ NiO ２ was prepared with reference to JP-A-2023-534756.

[0377] <Preparation of Positive Electrode> A commercially available carbon-coated aluminum foil with a thickness of 21 μm was prepared as a current collector. The positive electrode mixture sheet was placed on a carbon-coated copper foil, and the negative electrode mixture sheet and the current collector were bonded together using a roll press heated to 100° C. The sheet was then cut to a desired size and tabbed to form a negative electrode.

[0378] <Preparation of negative electrode mixture sheet> The active material (SiO ) and conductive additive (SuperP Li) were weighed, and the materials were added to a V-type mixer and mixed at 37 rpm for 10 minutes to obtain a mixture consisting of SiO and conductive additive. The mixture, the active material graphite, and the binder (PTFE powder X) were each weighed and placed in a container. After the active material and binder were sufficiently heated in a thermostatic bath at 80 ° C., fibrillation was promoted by treating with a Henschel mixer at 3000 rpm for 30 minutes to obtain a mixture. The mixture was further kneaded (50 rpm, 10 minutes) with a benchtop kneader (PN-1, manufactured by Irie Shokai) to promote fibrillation. Thereafter, the mixture was pulverized at 3000 rpm for 10 minutes with a Henschel mixer to promote fibrillation and enhance dispersibility, and an electrode mixture was obtained. The electrode mixture was placed between metal rolls arranged in parallel (left and right roll temperature: 100°C, left roll rotation speed: 1 m / min, right roll rotation speed: 0.4 m / min) and rolled to obtain a negative electrode mixture sheet with a thickness of approximately 180 μm. The composition ratio (mass ratio) was graphite:SiO:conductive additive:binder=94:1:1:4.

[0379] <Preparation of Negative Electrode> A commercially available carbon-coated copper foil with a thickness of 10 μm was prepared as a current collector. A negative electrode mixture sheet was placed on the carbon-coated copper foil, and the negative electrode mixture sheet and the current collector were bonded together using a roll press heated to 50° C. The sheet was then cut to a desired size and tabbed to form a negative electrode.

[0380] <Preparation of Electrolyte Solution> As an organic solvent, a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (EC:EMC = 30:70 (volume ratio)) was weighed into a sample bottle, and 3 mass % each of fluoroethylene carbonate (FEC) and vinylene carbonate (VC) was dissolved therein to prepare a mixed solution. LiPF was added to this mixed solution so that the concentration in the electrolyte solution was 1.1 mol / L. ６ The salts were mixed at 23° C. to obtain a non-aqueous electrolyte solution.

[0381] <Preparation of Aluminum Laminate Cell> The above positive electrode was placed opposite to the negative electrode via a 20 μm-thick microporous polyethylene film (separator), and the nonaqueous electrolyte solution obtained above was poured into the cell. After the nonaqueous electrolyte solution had sufficiently permeated the separator and the like, the cell was sealed to prepare a lithium ion secondary battery.

[0382] <Evaluation of Battery Characteristics (Initial Capacity, Capacity Retention Rate)> The lithium-ion secondary battery manufactured as described above was sandwiched between plates and pressurized, and tested at 60°C. It was charged at a constant current and constant voltage (0.1C cut) to 4.2 V at a current equivalent to 0.33 C, and then discharged to 3 V at a constant current of 0.33 C. This constituted one cycle, and the initial discharge capacity was calculated from the discharge capacity at the third cycle. Here, 1 C represents the current value at which the reference capacity of the battery is discharged in one hour; for example, 0.33 C represents one-third of that current value. After cycling, the ratio of the discharge capacity after 100 cycles to the initial discharge capacity was calculated, and this was defined as the cycle capacity retention rate (%). After cycling, the ratio of the discharge capacity after 100 cycles to the initial discharge capacity was calculated, and this was defined as the cycle capacity retention rate (%). (Discharge capacity after 103 cycles) ÷ (Discharge capacity at the third cycle) × 100 = Capacity Retention Rate (%). The capacity retention rate was evaluated according to the following criteria. ◎: 92% or more ○: 88% or more to less than 92% △: 85% or more to less than 88% ×: Less than 85% The results are shown in Table 2. The test results are the average value of N=4.

[0383]

[0384] Evaluation of Powder Flowability The powder flowability of Examples B1 and B2 and Comparative Example B1 was evaluated according to the following procedure.

[0385] <Powder Fluidity Evaluation> 80 g of the composition A prepared above was weighed and placed in a 250 ml plastic bottle, and the lid was tightened. The container was then placed on a mix rotor and rotated at 50 rpm for 4 hours. After rotation, the container was turned upside down, the composition was discharged, and the weight was measured to evaluate the amount of composition adhering to the container. (Example B1) The test was conducted in a dry room environment with a dew point of -40°C. Evaluation was conducted in the same manner using composition B as Example B2 and PTFE powder X as Comparative Example B1. The powder fluidity of each composition was evaluated according to the following criteria: ⊚: Adhesion amount less than 0.2 g ◯: Adhesion amount 0.2 to less than 0.5 g Δ: Adhesion amount 0.5 to less than 0.8 g ×: Adhesion amount 0.8 g or more The results are shown in Table 3.

[0386]

[0387] <Observation of Surface Coating> The active material of the positive electrode mixture in Examples A1 to A6 was observed immediately before being formed with the metal roll. The observation was performed using a scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) for Ni, Mn, Co, and Fe. As a result of observation at 3000x magnification, Li ５ FeO ４ In the mixed system, the presence of a coating layer was confirmed by observing the Fe element of the particles on the surface of the active material. ２ NiO ２ In the mixed system, the presence of a coating layer was confirmed by observing Ni element particles on which Mn and Co were not observed on the surface of the active material.

Claims

1. An electrochemical device including an electrode active material and a lithium supply agent in a positive electrode and / or a negative electrode, and including a fibrillatable resin in the positive electrode and / or the negative electrode.

2. The lithium replenisher is Li ５ FeO ４ , Li ５ AlO, and Li ２ NiO ２ The electrochemical device according to claim 1, which is at least one selected from the group consisting of 3. The lithium replenishing agent is Li ５ FeO ４ and Li ２ NiO ２ The electrochemical device according to claim 1 or 2, which is at least one selected from the group consisting of 4. The electrochemical device according to any one of claims 1 to 3, having a coating layer of the lithium supply agent on the surface of the electrode active material.

5. The electrochemical device according to any one of claims 1 to 4, wherein the negative electrode includes at least one selected from the group consisting of graphite and Si.

6. The electrochemical device according to any one of claims 1 to 5, wherein the positive electrode and / or the negative electrode including the fibrillatable resin is manufactured by a dry process.

7. The electrochemical device according to any one of claims 1 to 6, wherein the fibrillatable resin is a tetrafluoroethylene-based polymer.

8. The electrochemical device according to any one of claims 1 to 7, wherein the fibrillatable resin is polytetrafluoroethylene.

9. The electrochemical device according to any one of claims 1 to 8, wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene composed only of a polymerization unit based on a tetrafluoroethylene unit and a hexafluoropropylene unit.

10. The electrochemical device according to any one of claims 1 to 9, wherein the amount of the fibrillatable resin with respect to the electrode binder in the positive electrode and / or the negative electrode is 0.3 to 10% by mass.

11. The electrochemical device according to any one of claims 1 to 10, wherein the positive electrode includes the lithium supply agent and the fibrillatable resin.

12. The electrochemical device according to any one of claims 1 to 11, which is an electrolytic solution secondary battery or an electrolytic solution capacitor.

13. The electrochemical device according to any one of claims 1 to 12, which is a lithium ion secondary battery.

14. A composition including a lithium supply agent and a fibrillatable resin.

15. The composition according to claim 14, wherein the fibrillatable resin is at least one selected from the group consisting of a homopolymer of tetrafluoroethylene and a modified polytetrafluoroethylene composed only of a polymerization unit based on a tetrafluoroethylene unit and a hexafluoropropylene unit.

16. The lithium supplement is Li ５ FeO ４ and Li ２ NiO ２ The composition according to claim 14 or 15, which is at least one selected from the group consisting of 17. The composition according to any one of claims 14 to 16, wherein the total amount of the lithium supply agent and the fibrillatable resin with respect to the composition is 95% by mass or more.

18. The composition according to any one of claims 14 to 17, wherein the mass ratio of the fibrillatable resin to the Li replenisher (fibrillatable resin / Li replenisher) is 50 / 50 or more and 70 / 30 or less.

19. The composition according to any one of claims 14 to 18, wherein the liquid content is 10% by mass or less.

20. The composition according to any one of claims 14 to 19, which is a powder.

21. The composition according to any one of claims 14 to 20, which is a binder for an electrochemical device.

22. The composition according to any one of claims 14 to 21, which is a binder for a lithium-ion secondary battery.

23. An electrode mixture comprising the composition according to any one of claims 14 to 22 and an electrode active material.

24. The electrode mixture according to claim 23, which is a sheet.

25. An electrode comprising the composition according to any one of claims 14 to 22, an electrode active material, and a current collector.

26. A secondary battery comprising the electrode mixture according to claim 23 and a current collector.

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