Resin composition, battery binder, battery electrode composite layer, electrolyte layer, battery sheet, battery, and method for manufacturing the resin composition.

Abstract

A resin composition comprising: a compound including phosphorus and sulfur as constituent elements and having a disulfide bond; and a thermoplastic resin.

Description

[Technical Field]

[0001] The present invention relates to a resin composition that can be used as a battery binder and can suppress a decrease in ion conductivity, a battery binder, a battery electrode composite layer, an electrolyte layer, a battery sheet, a battery, and a method for producing the resin composition. [Background technology]

[0002] All-solid-state batteries, such as all-solid-state lithium-ion batteries, typically include a positive electrode layer, a solid electrolyte layer (sometimes simply called the "electrolyte layer"), and a negative electrode layer. By incorporating a binder into these layers, each layer or a laminate thereof can be formed into a sheet.

[0003] Non-patent documents 1 and 2 disclose the polymerization of PS4 on the surface of electrode active materials. Non-patent document 3 discloses the chemical structure change of 70Li2S-30P2S5 due to heat treatment. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Masato Sumita, et al., "Possible Polymerization of PS4 at a Li3PS4 / FePO4 Interface with Reduction of the FePO4 Phase," The Journal of Physical Chemistry C, April 24, 2017, Vol. 121, pp. 9698-9704. [Non-Patent Document 2] Takashi Hakari, et al., "Structural and Electronic-State Changes of a Sulfide Solid Electrolyte during the Li Deinsertion-Insertion Processes", Chemistry of Materials, May 3, 2017, Vol. 29, pp. 4768-4774 [Non-Patent Document 3] Yuichi Hasegawa, 'Chemical Structure Analysis of Sulfide-Based Solid Electrolyte 70Li2S-30P2S5', [online], February 1, 2018, Toray Research Center, Inc., [searched on July 9, 2019], Internet <URL:https: / / www.toray-research.co.jp / technical-info / trcnews / pdf / 201802-01.pdf> [Summary of the Invention]

[0005] It is conceivable to use polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), etc. as binders. However, when the addition amount of such a binder is increased to obtain the binding property between the materials constituting the layer (for example, electrode composite materials), there is a problem that the ionic conductivity decreases.

[0006] One of the objects of the present invention is to provide a resin composition that can be used as a binder for a battery and can suppress the decrease in ionic conductivity.

[0007] As a result of intensive studies, the present inventors have found that a resin composition containing a compound containing phosphorus and sulfur as constituent elements and having a disulfide bond and a thermoplastic resin can be used as a binder having ionic conductivity, and have completed the present invention. According to the present invention, the following resin compositions, etc. can be provided. 1. A resin composition containing a compound containing phosphorus and sulfur as constituent elements and having a disulfide bond, and a thermoplastic resin. 2. The resin composition according to 1, wherein the compound is obtained by oxidizing a raw material compound containing phosphorus and sulfur as constituent elements with an oxidizing agent. 3. The resin composition according to 1 or 2, wherein the compound contains a disulfide bond formed by any of the following reaction formulas (1) to (3).

Chemical formula

[0008] According to the present invention, a resin composition that can be used as a battery binder having ion conductivity can be provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is the Raman spectrum of compound α obtained in Example 1. [Modes for carrying out the invention]

[0010] The following describes in detail the resin composition, battery binder, battery electrode composite layer, electrolyte layer, battery sheet, battery, and method for manufacturing the resin composition of the present invention. In this specification, "x~y" represents a numerical range of "greater than or equal to x and less than or equal to y". The upper and lower limits specified for the numerical range can be combined in any way. A combination of two or more of the individual embodiments of the present invention described below is also an embodiment of the present invention.

[0011] 1.Resin composition A resin composition according to one aspect of the present invention comprises a compound containing phosphorus and sulfur as constituent elements and having a disulfide bond (hereinafter also referred to as "compound α") and a thermoplastic resin. Such resin compositions can be widely used as ion-conductive binders in various applications, including batteries.

[0012] <Compound α> Compound α contains phosphorus and sulfur as constituent elements and has a disulfide bond. In one embodiment, compound α has a peak derived from a disulfide bond that binds two phosphorus elements in Raman spectroscopy.

[0013] In one embodiment, compound α has a peak (hereinafter also referred to as "peak A") in the range of Raman shift of 425 cm -1 or more and 500 cm -1 or less, preferably 440 cm -1 or more and 490 cm -1 or less, more preferably 460 cm -1 or more and 480 cm -1 or less, and has a peak (hereinafter also referred to as "peak B") in the range of Raman shift of 370 cm -1 or more and 425 cm -1 less than, preferably 380 cm -1 or more and 423 cm -1 less than, more preferably 390 cm -1 or more and 420 cm -1 or less, and can be identified thereby. Incidentally, that compound α according to an embodiment of the present invention has a disulfide bond (S-S) may be identified by having peak A. Peak A is derived from a disulfide bond (S-S) that binds two phosphorus elements in compound α. Peak B is derived from the symmetric stretching by the P-S bond of the PS4 3- unit (also referred to as PS4 structure).

[0014] The Raman spectroscopy of compound α is performed by the method described in the examples. At this time, it is important to measure after treating compound α with toluene. This is to remove elemental sulfur that may be mixed in compound α. Elemental sulfur has a peak at a position that may overlap with peak A. Therefore, by removing elemental sulfur, peak A derived from compound α can be measured well. The toluene treatment is performed according to the procedure described in the examples.

[0015] Compound α according to one embodiment of the present invention preferably contains one or more elements selected from the group consisting of lithium, sodium, and magnesium as constituent elements. In one embodiment, these constituent elements are bonded to S in compound α by ionic bonds.

[0016] <Thermoplastic resin> The thermoplastic resin included in the resin composition is not particularly limited. In one embodiment, the thermoplastic resin is one or more selected from the group consisting of styrene-butadiene thermoplastic elastomers (SBS), cellulose derivatives such as ethylcellulose and carboxymethylcellulose (CMC), fluorine-based resins such as polyvinylidene fluoride and polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), polyethers such as polyethylene oxide (PEO) and polypropylene oxide, polyacrylonitrile, polyvinyl acetate, polymethyl methacrylate, polyphosphozene, polyvinylpyrrolidone, polyacrylic acid, and polyamide-imide resins.

[0017] Examples of styrene-butadiene thermoplastic elastomers (SBS) include block copolymers of polystyrene, which forms hard segments, and polybutadiene, which forms soft segments.

[0018] The mass ratio of compound α to thermoplastic resin in the resin composition is not particularly limited. In one embodiment, the mass ratio of compound α to thermoplastic resin in the resin composition (compound α: thermoplastic resin) is 99:1 to 1:99, 95:5 to 5:95, 90:10 to 10:90, 85:15 to 15:85, 80:20 to 20:80, 75:25 to 25:75, or 70:30 to 30:70.

[0019] <Halogen> In one embodiment, the resin composition further contains a halogen (a halogen-containing substance). The halogen may be a halogen derived from an oxidizing agent used in the production of compound α. In one embodiment, the halogen is one or more selected from the group consisting of iodine, fluorine, chlorine, and bromine. In one embodiment, the halogen is one or more selected from the group consisting of iodine and bromine.

[0020] The form of the halogen described above is not particularly limited and may be, for example, a salt of a halogen with one or more elements selected from the group consisting of lithium, sodium, magnesium, and aluminum, or one or more elements selected from the group consisting of elemental halogens. Examples of salts include LiI, NaI, MgI2, AlI3, LiBr, NaBr, MgBr2, and AlBr3. Among these, LiI and LiBr are preferred from the viewpoint of ionic conductivity. Examples of elemental halogens include iodine (I2), fluorine (F2), chlorine (Cl2), and bromine (Br2). Among these, iodine (I2) and bromine (Br2) are preferred from the viewpoint of reducing corrosion when they remain in the binder (A). In one embodiment, the battery binder (A) may have higher ionic conductivity by containing a halogen as the aforementioned salt.

[0021] The content of halogen-containing substances (elemental halogens and halogen compounds) in the resin composition is not particularly limited. For example, from the viewpoint of the conductivity of carrier ions and the bonding strength of the active material and solid electrolyte, when the total mass of the resin composition is taken as 100% by mass, the content may be 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 8% by mass or less, 5% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.05% by mass or less, or 0.01% by mass or less.

[0022] The content of compound α, the resin composition, and the halogen-containing substance in the resin composition is not particularly limited. In one embodiment, the resin composition is composed of 50% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, 85% or more by mass, 90% or more by mass, 95% or more by mass, 98% or more by mass, 99% or more by mass, 99.5% or more by mass, 99.8% or more by mass, 99.9% or more by mass, or substantially 100% by mass of compound α and the resin composition, or compound α, a thermoplastic resin and a halogen-containing substance. Furthermore, in the case of "substantially 100% by mass," it is acceptable for unavoidable impurities to be present.

[0023] 2. Battery Binder A battery binder according to one aspect of the present invention (hereinafter referred to as battery binder (A)) comprises the resin composition described above. In one embodiment, the battery binder (A) is made of the resin composition described above.

[0024] The battery binder (A) can be used in various types of batteries. Examples of batteries include secondary batteries such as lithium-ion batteries. The battery may also be an all-solid-state battery. The "binder" is incorporated into such a battery by being one or more of the elements selected from the group consisting of, for example, a battery electrode composite layer and an electrolyte layer, and can exhibit binding properties (also called "binding force" or "adhesion force") to bind other components contained in the element (e.g., a layer) together and maintain unity.

[0025] Conventional battery electrode composite layers (for example, the positive or negative electrode described later) have difficulty following the expansion and contraction (volume change) of the electrode active material due to charging and discharging, etc., and are prone to problems such as capacity degradation. The electrolyte layer adjacent to the battery electrode composite layer is also affected by the volume change of the battery electrode composite layer and may also suffer from degradation and other problems. In contrast, by using a battery binder (A), the battery electrode composite layer or electrolyte layer can absorb the volume change due to the flexibility of the battery binder (A), and capacity degradation and other problems can be prevented. As a result, the battery can exhibit excellent cycle characteristics. Furthermore, since the battery binder (A) itself may have ionic conductivity, even if the amount of battery binder (A) added is increased to improve the bonding between the materials constituting the layer (for example, the electrode composite), the decrease in ionic conductivity can be suppressed, and the battery characteristics can be exhibited well. Furthermore, in one embodiment, the battery binder (A) has superior heat resistance compared to ordinary organic binders and polymer solid electrolytes (e.g., polyethylene oxide), thus expanding the operating temperature range of the battery.

[0026] Furthermore, the battery binder (A) has the effect of improving coating properties because the thermoplastic resin functions as a thickener. For example, a coating solution (slurry) obtained by adding the solvent described later to the battery binder (A) has excellent coating properties. This also improves the uniformity of the coating film. Furthermore, the ion conductivity of the battery binder (A) can be adjusted by selecting a thermoplastic resin. For example, by selecting a polymer electrolyte such as a polyethylene oxide composite containing an electrolyte salt as the thermoplastic resin, the ion conductivity can be improved.

[0027] 3. Electrode composite layer or electrolyte layer for batteries An electrode composite layer or electrolyte layer for a battery according to one aspect of the present invention includes the above-described battery binder (A). In one embodiment, the battery binder (A) is either unevenly distributed or uniformly distributed (dispersed) within the battery electrode composite layer or electrolyte layer. In one embodiment, the uniform distribution (dispersion) of the battery binder (A) within the layer helps to maintain better integrity of the layer.

[0028] The electrode composite layer or electrolyte layer for the battery preferably contains a solid electrolyte other than the battery binder (A) (hereinafter referred to as solid electrolyte (B)). The solid electrolyte (B) is not particularly limited, and for example, oxide solid electrolytes and sulfide solid electrolytes can be used. Among these, sulfide solid electrolytes are preferred, specifically argyrodite type crystal structure, Li3PS4 crystal structure, Li4P2S6 crystal structure, Li7P3S 11 Crystal structure, Li 4-x Ge 1-x P x S4-type thio-LISICON region II crystal structure, Li 4-x Ge 1-x P x Examples include sulfide solid electrolytes having a crystal structure similar to that of the S4-type thio-LISICON region II (hereinafter sometimes abbreviated as RII-type crystal structure).

[0029] Examples of electrode composite layers for batteries include positive electrodes and negative electrodes. When the electrode composite layer for a battery is the positive electrode, the positive electrode may further contain a positive electrode active material. The positive electrode active material is a material that allows for the insertion and removal of lithium ions, and any material known as a positive electrode active material in the battery field can be used.

[0030] Examples of positive electrode active materials include metal oxides and sulfides. Sulfides include metallic sulfides and nonmetallic sulfides. Metal oxides include, for example, transition metal oxides. Specifically, V2O5, V6O 13 , LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li(Ni a Co b Mnc )O2 (where 0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1), LiNi 1-Y Co Y O2, LiCo 1-Y Mn Y O2, LiNi 1-Y Mn Y O2 (where 0 ≤ Y < 1), Li(Ni a Co b Mn c )O4 (0 < a < 2, 0 < b < 2, 0 < c < 2, a + b + c = 2), LiMn 2-Z Ni Z O4, LiMn 2-Z Co Z O4 (where 0 < Z < 2), LiCoPO4, LiFePO4, CuO, Li(Ni a Co b Al c )O2 (where 0 < a < 1, 0 < b < 1, 0 < c < 1, a + b + c = 1), etc. can be mentioned. As metal sulfides, lithium sulfide (Li2S), polysulfide lithium (Li2Sx, 1 < x ≤ 8), titanium sulfide (TiS2), molybdenum sulfide (MoS2), iron sulfide (FeS, FeS2), copper sulfide (CuS), nickel sulfide (Ni3S2), etc. can be mentioned. In addition, as metal oxides, bismuth oxide (Bi2O3), bismuth lead oxide (Bi2Pb2O5), etc. can be mentioned. As non-metal sulfides, elemental sulfur, organic disulfide compounds, carbon sulfide compounds, etc. can be mentioned. In addition to the above, niobium selenide (NbSe3), metallic indium, and sulfur can also be used as the positive electrode active material.

[0031] When the electrode composite layer for the battery is the negative electrode, the negative electrode can further contain a negative electrode active material. The negative electrode active material can be any material commonly used in lithium-ion secondary batteries, such as carbon materials like graphite, natural graphite, artificial graphite, hard carbon, and soft carbon; polyacene-based conductive polymers and composite metal oxides like lithium titanate; or compounds that form alloys with lithium, such as silicon, silicon alloys, silicon composite oxides, tin, and tin alloys. Among these, the negative electrode active material preferably contains one or more selected from the group consisting of Si (silicon, silicon alloys, silicon-graphite composites, silicon composite oxides, etc.) and Sn (tin, tin alloys).

[0032] The positive electrode and / or the negative electrode may contain a conductive additive. It is preferable to add a conductive additive when the electronic conductivity of the active material is low. This can improve the rate characteristics of the battery.

[0033] Specific examples of conductive additives include, preferably, carbon materials, substances containing at least one element selected from the group consisting of nickel, copper, aluminum, indium, silver, cobalt, magnesium, lithium, chromium, gold, ruthenium, platinum, beryllium, iridium, molybdenum, niobium, osnium, rhodium, tungsten, and zinc, and more preferably elemental carbon or carbon materials other than elemental carbon with high conductivity; and elemental metals, mixtures, or compounds containing nickel, copper, silver, cobalt, magnesium, lithium, ruthenium, gold, platinum, niobium, osnium, or rhodium. Specific examples of carbon materials include carbon blacks such as Ketjenblack, acetylene black, Denka black, thermal black, and channel black; graphite, carbon fiber, and activated carbon. These can be used individually or in combination of two or more. Among these, acetylene black, including Denka black, and Ketjenblack, which have high electronic conductivity, are preferred.

[0034] The electrolyte layer contains a battery binder (A) and may optionally contain a solid electrolyte (B) other than the battery binder (A).

[0035] The composition of the positive electrode is not particularly limited; for example, the mass ratio could be positive electrode active material: solid electrolyte (B): battery binder (A): conductive additive = 50~99:0~30:1~30:0~30. 30% or more by mass of the positive electrode, 50% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, 98% or more by mass, and 99% or more by mass may be the positive electrode active material, solid electrolyte (B), battery binder (A), and conductive additive.

[0036] The composition of the negative electrode is not particularly limited; for example, the mass ratio could be negative electrode active material: solid electrolyte (B): battery binder (A): conductive additive = 40~99:0~30:1~30:0~30. 30% or more by mass of the negative electrode, 50% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, 98% or more by mass, and 99% or more by mass may be the negative electrode active material, solid electrolyte (B), battery binder (A), and conductive additive.

[0037] The composition of the electrolyte layer is not particularly limited; for example, the mass ratio of solid electrolyte (B):battery binder (A) may be 99.9:0.1 to 0:100. When the mass ratio of the solid electrolyte (B) is 0, the battery binder (A) can also function as the solid electrolyte. 30% or more by mass, 50% or more by mass, 80% or more by mass, 90% or more by mass, 95% or more by mass, 98% or more by mass, 99% or more by mass, or 99.9% or more by mass of the electrolyte layer may be a solid electrolyte (B) and a battery binder (A).

[0038] The method for forming layers containing compound α and thermoplastic resin, for example, the method for forming each layer constituting the battery described above, is not particularly limited and can be, for example, a coating method. In the coating method, a coating solution can be used in which the components contained in each layer are dissolved or dispersed in a solvent. As solvents to be contained in the coating solution, chain, cyclic or aromatic ethers (e.g., dimethyl ether, dibutyl ether, tetrahydrofuran, anisole, etc.), esters (e.g., ethyl acetate, ethyl propionate, etc.), alcohols (e.g., methanol, ethanol, etc.), amines (e.g., tributylamine, etc.), amides (e.g., N-methylformamide, etc.), lactams (e.g., N-methyl-2-pyrrolidone, etc.), hydrazine, acetonitrile, etc. After coating, the solvent is dried to form the layers (dried coating films). From the viewpoint of ease of drying of the solvent, anisole is preferred. The drying method is not particularly limited and can be, for example, one or more means selected from the group consisting of heating drying, forced-air drying and reduced-pressure drying (including vacuum drying).

[0039] The component to which the coating solution is applied is not particularly limited. The formed layer may be used in the battery together with the component, or the formed layer may be peeled off from the component and used in the battery. In one embodiment, the coating solution for forming the positive electrode is applied on the positive electrode current collector. In one embodiment, the coating solution for forming the negative electrode is applied on the negative electrode current collector. In one embodiment, the coating solution for forming the electrolyte layer is applied on the positive electrode or the negative electrode. In one embodiment, the coating solution for forming the electrolyte layer is applied on an easily peelable component, and then the formed layer is peeled off from the easily peelable component and placed between the positive electrode and the negative electrode.

[0040] It is preferable to press the dried coating (layer). The pressing can be any method that compresses the layer by pressing it. For example, pressing can be applied to reduce the porosity within the layer. The pressing device is not particularly limited, and for example, a roll press or a uniaxial press can be used. The temperature during pressing is not particularly limited, and may be around room temperature (23°C), or it may be lower or higher than room temperature. By applying the press, the battery binder (A) contained in the layer is suitably deformed due to its flexibility, and the formation of interfaces between the electrode composite materials contained in the layer is promoted. This further improves the battery characteristics.

[0041] The pressing may be applied to each layer individually, or it may be applied to multiple stacked layers (for example, the "battery sheet" described later) by pressing the multiple layers in the stacking direction.

[0042] 4. Battery sheet A battery sheet according to one aspect of the present invention comprises one or more components selected from the group consisting of the electrode composite layer and the electrolyte layer described above. The battery sheet, by containing compound α and a thermoplastic resin or a battery binder (A), exhibits excellent flexibility and prevents breakage and peeling from the current collector.

[0043] 5.Battery A battery according to one aspect of the present invention includes the resin composition described above. In one embodiment, the battery is an all-solid-state battery. In one embodiment, the all-solid-state battery includes a laminate comprising a positive electrode current collector, a positive electrode, an electrolyte layer, a negative electrode, and a negative electrode current collector in that order. As the current collector, plate-shaped or foil-shaped bodies made of copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, aluminum, germanium, indium, lithium, or alloys thereof can be used. The battery preferably contains one or more components selected from the group consisting of a positive electrode, an electrolyte layer, and a negative electrode, which are the resin compositions described above.

[0044] The above description (and the examples described later) mainly describes the use of the resin composition according to the present invention in a battery, but it is not limited to this. Because the resin composition according to the present invention has excellent flexibility, ionic conductivity, etc., it can be widely applied to various uses.

[0045] 6. Method for producing compound α The method for producing compound α described above is not particularly limited. In one embodiment, the method for producing compound α includes adding an oxidizing agent to a raw material compound containing phosphorus and sulfur as constituent elements, and reacting the raw material compound with the oxidizing agent. Compound α is obtained as a product by reacting the above raw material compound with an oxidizing agent. In one embodiment, compound α is obtained by oxidizing a raw material compound containing phosphorus and sulfur as constituent elements with an oxidizing agent.

[0046] In one embodiment, the raw material compound (hereinafter referred to as raw material compound (C)) contains phosphorus and sulfur as constituent elements. The raw material compound (C) preferably contains one or more elements selected from the group consisting of lithium, sodium, magnesium, and aluminum as constituent elements. In one embodiment, the raw material compound (C) preferably contains a PS4 structure. Examples of raw material compounds containing a PS4 structure include Li3PS4 and Li4P2S. 7、 Examples include Na3PS4 and Na4P2S7. Furthermore, the starting compound (C) may contain two or more PS4 structures, such as Li4P2S7 and Na4P2S7. Here, if the starting compound (C) contains two adjacent PS4 structures, these two PS4 structures may share one sulfur atom. Li3PS4 can be produced, for example, by reacting Li2S and P2S5 in the presence of a dispersion medium using a mechanochemical method (mechanical milling). Examples of dispersion mediums include n-heptane. For the mechanochemical method, for example, a planetary ball mill can be used. In one embodiment, compound α can be produced by reacting Li2S, P2S5, and an oxidizing agent in the presence of a dispersion medium (e.g., n-heptane) using a mechanochemical method (mechanical milling). Here, too, a planetary ball mill or the like can be used for the mechanochemical method. In the above explanation, Na2S may be used instead of Li2S.

[0047] Examples of oxidizing agents include elemental halogens, oxygen and ozone, oxides (Fe2O3, MnO2, Cu2O, Ag2O, etc.), oxo salts (chlorates, hypochlorites, iodates, bromates, chromates, permanganates, vanadates, bismuthates, etc.), peroxides (lithium peroxide, sodium peroxide, etc.), halide salts (AgI, CuI, PbI2, AgBr, CuCl, etc.), cyanide salts (AgCN, etc.), thiocyanates (AgSCN, etc.), and sulfoxides (dimethyl sulfoxide, etc.). In one embodiment, the oxidizing agent is preferably an elemental halogen from the viewpoint of enhancing ionic conductivity with metal halides generated as by-products. The "metal halide" may be a salt of a halogen with one or more elements selected from the group consisting of lithium, sodium, magnesium, and aluminum derived from the raw material compound (C) (for example, lithium halide if the raw material compound (C) contains lithium). Examples of elemental halogens include iodine (I2), fluorine (F2), chlorine (Cl2), and bromine (Br2). From the viewpoint of obtaining higher ionic conductivity, iodine (I2) and bromine (Br2) are preferred as the elemental halogens. As an oxidizing agent, one type may be used alone, or multiple types may be used in combination.

[0048] In one embodiment, when the starting compound (C) is Li3PS4 and the oxidizing agent is an elemental halogen (X2), the reaction shown in the following reaction formulas (1) to (3) proceeds. In one embodiment, compound α has a PSS chain (a chain made up of repeating units consisting of PSS) (reaction formulas (1) and (2)). In one embodiment, the PSS chain of compound α forms a branching structure (reaction formula (3)). In one embodiment, two phosphorus elements and a disulfide bond connecting these two phosphorus elements constitute the PSS chain. [ka] (In the equation, X is a halogen, and n is an integer.)

[0049] In one embodiment, compound α contains a disulfide bond formed by any of the reaction formulas (1) to (3).

[0050] In one embodiment, X in reaction formulas (1) to (3) is iodine (I), fluorine (F), chlorine (Cl), or bromine (Br). In one embodiment, X in reaction equations (1) to (3) is iodine (I).

[0051] The molar ratio (Li3PS4:I2) of Li3PS4 to I2 used in the reaction (combined) is not particularly limited and may be, for example, 10:1 to 1:10, 5:1 to 1:5, 3:1 to 1:3, 2:1 to 1:2, 4:3 to 3:4, 5:4 to 4:5, or 8:7 to 7:8. Furthermore, the amount of I2 added may be 0.1 moles or more, 0.2 moles or more, 0.5 moles or more, 0.7 moles or more, or 1 mole or more per 100 moles of Li3PS4, and may also be 300 moles or less, 250 moles or less, 200 moles or less, 180 moles or less, 150 moles or less, 130 moles or less, 100 moles or less, 80 moles or less, 50 moles or less, 30 moles or less, 20 moles or less, 15 moles or less, 10 moles or less, 8 moles or less, 5 moles or less, 3 moles or less, or 2 moles or less. The higher the proportion of I2, the longer the PSS chain can be extended. Furthermore, the above molar ratio relationship is not limited to the reaction of Li3PS4 and I2, but also applies to PS4 structures, for example. m This method can also be applied when reacting a starting compound containing a (m=3, 3.5, 4) unit structure (or the raw materials for said starting compound; for example, a combination of Li2S and P2S5, a combination of Na2S and P2S5, etc.) with an elemental halogen.

[0052] In the step of reacting the raw material compound (C) and the oxidizing agent (reaction step), it is preferable to react the raw material compound (C) and the oxidizing agent with one or more energies selected from the group consisting of physical energy, thermal energy, and chemical energy. In the reaction step, it is preferable to react the starting compound (C) and the oxidizing agent using energy, including physical energy. Physical energy can be supplied, for example, by using a mechanochemical method (mechanical milling). For the mechanochemical method, for example, a planetary ball mill can be used. In mechanochemical processes using planetary ball mills, etc., the processing conditions are not particularly limited. For example, the rotational speed may be 100 rpm to 700 rpm, the processing time may be 1 hour to 100 hours, and the ball diameter may be 1 mm to 10 mm. In the reaction process, it is preferable to react the starting compound (C) and the oxidizing agent in liquid. In this case, the starting compound (C) and the oxidizing agent can be reacted in the presence of a dispersion medium. Reacting the starting compound (C) and the oxidizing agent in the presence of a dispersion medium by a mechanochemical method (mechanical milling) is preferable from the viewpoint of improving reactivity through mechanical energy. Examples of dispersion media include aprotic liquids. Aprotic liquids are not particularly limited and include, for example, linear or cyclic alkanes, preferably having 5 or more carbon atoms, such as n-heptane; aromatic hydrocarbons, such as benzene, toluene, xylene, and anisole; linear or cyclic ethers, such as dimethyl ether, dibutyl ether, and tetrahydrofuran; alkyl halides, such as chloroform and methylene chloride; and esters, such as ethyl propionate.

[0053] In one embodiment, when the raw material compound (C) and the oxidizing agent are reacted in a liquid, the reaction can be carried out with one or both of the raw material compound (C) and the oxidizing agent mixed with the solvent. As the solvent, any dispersion medium capable of dissolving either or both of the starting compound (C) and the oxidizing agent can be used from among those mentioned above. For example, anisole and dibutyl ether are preferred. Even in such a solution, the starting compound (C) and the oxidizing agent can be reacted by one or more energies selected from the group consisting of physical energy such as stirring, milling, and ultrasonic vibration, as well as thermal energy and chemical energy. For example, when using thermal energy, the solution can be heated. The heating temperature is not particularly limited and may be, for example, 40-200°C, 50-120°C, or 60-100°C.

[0054] In the reaction process, compound α can be produced by oxidizing the starting compound (C) with an oxidizing agent.

[0055] If compound α is produced by a reaction in liquid, the liquid (dispersion medium or solvent) can be removed as needed. By removing the liquid, a solid (powder) of compound α can be obtained. The method of removing the liquid is not particularly limited and includes, for example, drying, solid-liquid separation, and two or more of these methods may be combined. When using solid-liquid separation, compound α may be reprecipitated. In this case, compound α can be recovered as a solid (solid phase) by adding the liquid containing compound α to a poor solvent (a poor solvent for compound α) or a non-solvent (a solvent that does not dissolve compound α). For example, a method of solid-liquid separation can be used by adding an anisole solution containing compound α to n-heptane, which is a poor solvent. The solid-liquid separation method is not particularly limited and can be, for example, evaporation, filtration, or centrifugation. When using solid-liquid separation, the effect of improving purity can be obtained.

[0056] In one embodiment, LiI is produced as a by-product during the formation of compound α. This LiI may or may not be separated from compound α. As described above, by leaving LiI as a mixture, compound α may have higher ionic conductivity. Here, the crystalline phase of LiI can be, for example, c-LiI (cubic) (ICSD 414244), h-LiI (hexagonal) (ICSD 414242), etc. Typically, when compound α is produced using a mechanochemical method (mechanical milling), c-LiI (cubic) is produced, while when a method of reaction in liquid (preferably in solution) is used, h-LiI (hexagonal) is produced. The crystalline phase of LiI can be determined by powder X-ray diffraction or solid-state diffraction. 7 This can be determined by Li-NMR measurement. (Solid state) 7 In Li-NMR measurements, if a peak originating from LiI (chemical shift -4.57 ppm) is observed, it is determined to be c-LiI; if no peak originating from LiI is observed, it is determined to be h-LiI.

[0057] 7. Method for producing resin compositions The method for producing a resin composition according to one aspect of the present invention is not particularly limited. A method for producing a resin composition according to one aspect of the present invention includes adding an oxidizing agent to a raw material compound containing phosphorus and sulfur as constituent elements, oxidizing the raw material compound, and mixing the compound obtained by the oxidation with a thermoplastic resin. This makes it possible to manufacture a resin composition according to one aspect of the present invention.

[0058] In one embodiment, a compound obtained by oxidation is mixed with a thermoplastic resin and one or more components other than compound α and the thermoplastic resin described in "3. Electrode composite layer or electrolyte layer for batteries" (for example, a solid electrolyte). This makes it possible to produce a resin composition suitable for use as an electrode composite layer or electrolyte layer for batteries. [Examples]

[0059] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0060] (Example 1) (1) Manufacturing of Li3PS4 glass 1.379 g of Li2S (manufactured by Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh) and 2.222 g of P2S5 (manufactured by Merck) were reacted in the presence of a dispersion medium (n-heptane) by a mechanochemical method (mechanical milling) using a planetary ball mill (Premium Line PL-7 (Fritsch)) under the following conditions. The dispersion medium was then removed by drying to obtain Li3PS4 glass (powder). [Conditions for mechanical milling] Sample mass: 3.6g Format: Wet milling (n-heptane: 11.7 mL) Ball: Material ZrO2, diameter 5mm, total weight 106g Pot: Material: ZrO2, Capacity: 80mL Rotation: 500 rpm Processing time: 20 hours

[0061] (2) Preparation of compound α To the Li3PS4 glass obtained in "(1) Manufacturing of Li3PS4 glass" described above, I2 (5N irregular grains (high-purity chemicals)) was crushed in a mortar and added in a molar ratio of Li3PS4:I2 = 1:1. Next, Li3PS4 glass and I2 were reacted in the presence of a dispersion medium (n-heptane) by a mechanochemical method (mechanical milling) using a planetary ball mill (Premium Line PL-7 (Fritsch)) under the following conditions. Then, the dispersion medium was removed by drying to obtain compound α (powder). [Conditions for mechanical milling] Sample mass: 1g Format: Wet milling (n-heptane: 3mL) Ball: Material ZrO2, diameter 5mm, total weight 53g Pot: Material: ZrO2, Capacity: 45mL Rotation: 500 rpm Processing time: 20 hours

[0062] (3) Raman spectroscopy The compound α (powder) obtained in "(2) Production of compound α" above was subjected to the following toluene treatment, and then micro-Raman spectroscopy was performed using a laser Raman spectrophotometer ("NRS-3100" manufactured by JASCO Corporation).

[0063] [Toluene treatment procedure] a. Place 1 g of compound α in a vial, add 10 mL of toluene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated), stir, and let stand. b. After removing the supernatant, add another 10 mL of toluene to the solids (precipitation), stir, and let stand. c. Repeat the operation in b above once. d. After removing the supernatant, the solid (precipitate) is vacuum-dried at 60°C for 10 hours to obtain toluene-treated compound α.

[0064] Figure 1 shows the Raman spectrum obtained by micro-Raman spectroscopy. The Raman shift of 475 cm⁻¹ originates from the disulfide (SS) bond in the PSS chain. -1 A nearby peak was identified.

[0065] (4) Preparation of the coating solution A coating solution with the following composition was prepared. [Composition of the coating solution] Li3PS4 solid electrolyte (Li3PS4 glass obtained in "(1) Manufacturing of Li3PS4 glass" above): 95 parts by mass Compound α (powder): 3.5 parts by mass Styrene-butadiene thermoplastic elastomer (SBS) (JSR Corporation "TR2000"): 1.5 parts by mass Anisole: 81 parts by mass per 100 parts by mass of the total amount of the above three components (solids)

[0066] Specifically, first, SBS was dissolved in anisole to prepare a 20% by mass SBS solution. Then, 0.06 g of the SBS solution and 0.400 mL of anisole were added to 0.028 g of compound α (powder) and dissolved. Next, 0.76 g of Li3PS4 solid electrolyte was added to the solution, and the mixture was kneaded using a planetary stirring and defoaming apparatus (MAZERUSTAR KK-250S manufactured by Kurabo Industries Ltd.) under the following kneading conditions. [Mixing conditions] Rotation: 1600 rpm Revolution: 1600 rpm Processing time: 180 seconds x 3 Next, the sample was treated in an ultrasonic cleaner for 5 minutes, and then re-kneaded under the same kneading conditions as described above. Next, 0.2 mL of anisole was added to the sample and kneaded further under the same kneading conditions as above to obtain a slurry-like resin composition (slurry solid content concentration 55% by mass).

[0067] (5) Manufacturing of battery sheets The coating solution obtained in "(4) Preparation of coating solution" above was applied to a 5cm x 10cm piece of aluminum foil to form a coating film. The coating film was then dried at 60°C for 10 hours to remove the solvent (anisole) and a solid electrolyte sheet (battery sheet) was manufactured.

[0068] (6) Measurement of ionic conductivity The solid electrolyte sheet obtained in "(5) Manufacturing of Battery Sheets" above was punched out into a disc shape along with the aluminum foil, placed in a cylindrical container, and pressed at a pressure of 333 MPa at room temperature (23°C) by sandwiching it between cylindrical SUS shafts inserted from both ends of the container. The thickness of the pressed solid electrolyte sheet is shown in Table 1. While maintaining the pressed state, lead wires were connected to the solid electrolyte sheet and the ionic conductivity was measured. A Solartron Analytical "Cell test system 1470E" was used for the measurement. Table 1 shows the ionic conductivity calculated based on the thickness of the pressed solid electrolyte sheet.

[0069] (7) Evaluation of adhesive strength 1 The solid electrolyte sheet obtained in "(5) Manufacturing of Battery Sheets" above was punched out into a disc shape together with the aluminum foil, wrapped around a cylinder with a diameter of 16 mm, and the presence or absence of breakage of the solid electrolyte sheet or peeling from the aluminum foil was visually observed, and the adhesive strength 1 was evaluated according to the evaluation criteria below. [Evaluation Criteria] A: No rupture of the solid electrolyte sheet or delamination from the aluminum foil was observed in either punching or wrapping around a cylinder. B: During punching or wrapping onto a cylinder, rupture of the solid electrolyte sheet or delamination from the aluminum foil is observed.

[0070] (8) Evaluation of adhesive strength 2 After applying tape to the surface of the solid electrolyte sheet obtained in "(5) Manufacturing of Battery Sheets" above, the tape was peeled off, and the presence or absence of peeling of the solid electrolyte sheet from the aluminum foil was visually observed, and the adhesive strength 2 was evaluated according to the evaluation criteria below. [Evaluation Criteria] AA: Neither delamination of the solid electrolyte sheet from the aluminum foil nor intralayer delamination of the solid electrolyte sheet was observed. A: No delamination of the solid electrolyte sheet from the aluminum foil is observed, but intralayer delamination of the solid electrolyte sheet is observed. B: Peeling of the solid electrolyte sheet from the aluminum foil is observed.

[0071] (Example 2) In Example 1, the procedure was the same as in Example 1 except that the composition of the coating solution was changed as follows. [Composition of the coating solution] Li3PS4 solid electrolyte: 95 parts by mass Compound α (powder): 2.5 parts by mass Styrene-butadiene thermoplastic elastomer (SBS): 2.5 parts by mass Anisole: 85 parts by mass per 100 parts by mass of the total amount of the above three components (solids)

[0072] (Example 3) In Example 1, the procedure was the same as in Example 1 except that the composition of the coating solution was changed as follows. [Composition of the coating solution] Li3PS4 solid electrolyte: 95 parts by mass Compound α (powder): 1.5 parts by mass Styrene-butadiene thermoplastic elastomer (SBS): 3.5 parts by mass Anisole: 89 parts by mass per 100 parts by mass of the total amount of the above three components (solids)

[0073] (Comparative Example 1) In Example 1, the procedure was the same as in Example 1 except that the composition of the coating solution was changed as follows. [Composition of the coating solution] Li3PS4 solid electrolyte: 95 parts by mass Styrene-butadiene thermoplastic elastomer (SBS): 5.0 parts by mass Anisole: 82 parts by mass per 100 parts by mass of the total amount of the above two components (solids)

[0074] (Comparative Example 2) In Example 1, an attempt was made to produce a battery sheet using the same procedure as in Example 1 (5), except that the composition of the coating solution was changed as follows. However, peeling of the solid electrolyte sheet from the aluminum foil occurred, making it impossible to evaluate each physical property. [Composition of the coating solution] Li3PS4 solid electrolyte: 100 parts by mass Anisole: 99 parts by mass per 100 parts by mass of the above Li3PS4 solid electrolyte (solid content)

[0075] (Comparative Example 3) In Example 1, the procedure was the same as in Example 1 except that the composition of the coating solution was changed as follows. [Composition of the coating solution] Li3PS4 solid electrolyte: 95 parts by mass Compound α (powder): 5.0 parts by mass Anisole: 87 parts by mass per 100 parts by mass of the total amount of the above two components (solids)

[0076] The results are shown in Table 1.

[0077] [Table 1]

[0078] <Rating> Table 1 shows that by using a resin composition containing compound α and a thermoplastic resin as a binder, it is possible to suitably achieve both ionic conductivity and adhesive strength.

[0079] (Example 4) (A) Production of argyrodite-type solid electrolytes 0.492 g of Li2S (manufactured by Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh), 0.626 g of P2S5 (manufactured by Merck), and 0.382 g of LiCl (manufactured by Nacalai Tesque) were reacted under the following conditions using a mechanochemical method (mechanical milling) with a planetary ball mill (P-7, manufactured by Fritsch) to obtain a precursor of an argyrodite-type solid electrolyte. [Conditions for mechanical milling] Sample mass: 1.5g Type: Dry milling Ball: Material: ZrO2, Diameter: 10mm, Total weight: 32g Pot: Material: ZrO2, Capacity: 45mL Rotation speed: 370 rpm Processing time: 15 hours

[0080] The above mechanical milling was performed twice to obtain approximately 2.6 g of argyrodite-type solid electrolyte precursor. The precursor was placed in a quartz tube and heat-treated at 430°C for 8 hours under an argon flow atmosphere to produce the argyrodite-type solid electrolyte. After grinding the argyrodite-type solid electrolyte in a mortar, it was further refined using a planetary ball mill (the same apparatus as described above) under the following conditions to obtain the argyrodite-type solid electrolyte (powder). The refinement process was carried out in two stages.

[0081] [Conditions for miniaturization process] Sample mass: 1.5g Format: Wet milling (toluene: 15.5 mL, isobutyronitrile: 3.9 mL) Ball: Material: ZrO2, Diameter: 0.5mm, Total weight: 34g Pot: Material: ZrO2, Capacity: 45mL Milling conditions: Stage 1, 370 rpm for 30 minutes Second stage, 150 rpm for 1 hour

[0082] (B) Preparation of the positive electrode composite layer (positive electrode sheet) (1) LiNbO3 coating on the positive electrode active material LiRing 1 / 3 Co 1 / 3 Mn 1 / 3 2 g of O2 (NMC, MTI) was weighed, and 3 mL of LiNb(OEt)6 (Alfa Aesar, lithium niobethoxide, 99+% (metal-based), 5% w / v in ethanol) was added to it. Next, 7 mL of super-dehydrated ethanol (Fujifilm Wako Pure Chemical Industries, Ltd.) was added. The resulting sample was treated in an ultrasonic cleaner for 30 minutes and dried in an Ar atmosphere at 40°C for 10 hours. Furthermore, the sample was vacuum-dried at 100°C for 1 hour. The dried sample was placed in a desiccator with a relative humidity of approximately 40% to 50% and allowed to proceed with the hydrolysis reaction for 10 hours. Next, the reacted sample was heat-treated at 350°C for 1 hour to produce LiNi coated with LiNbO3. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (LiNbO3-coated NMC) was obtained. The LiNbO3 content in the obtained LiNbO3-coated NMC was 3% by mass.

[0083] (2) Preparation of binder solution First, SBS was dissolved in anisole to prepare a 20% by mass SBS solution. 0.495 g of the SBS solution and 0.45 mL of anisole were added to 0.0396 g of compound α (powder) from Example 1 and dissolved.

[0084] (3) Preparation of the positive electrode sheet LiNbO3-coated NMC, the argyrodite-type solid electrolyte (SE) obtained in (A) above, and acetylene black (AB) (manufactured by Denka Co., Ltd.) were mixed in a mass ratio of LiNbO3-coated NMC:SE:AB = 85:15:1 (total mass 1g). The binder solution was added to the resulting mixture. The composition after addition was LiNbO3-coated NMC:SE:compound α:SBS:AB = 85:15:4:1:1. This composition was kneaded to obtain a slurry (solid content concentration 68% by mass). The obtained slurry was applied to a 5 × 10 cm Al foil to form a coating film. The coating film was dried at 60°C for 10 hours, and then vacuum dried at 160°C for 3 hours. The obtained sheet was punched out to obtain a positive electrode sheet with a diameter of 9.9 mm. The positive electrode sheet did not break or peel off from the aluminum foil even when wrapped around a 16mm diameter cylinder. Furthermore, the positive electrode sheet could be easily punched out.

[0085] (Example 5) <Fabrication of all-solid-state batteries> An argyrodite-type solid electrolyte (100 mg) prepared in the same manner as in Example 4(A) was placed in a cylindrical container with SUS shafts on both sides and compacted to form a solid electrolyte layer. Next, the positive electrode sheet obtained in Example 4 was placed in the cylindrical container so as to overlap with the solid electrolyte layer. Furthermore, In foil and Li foil were placed in that order on the side of the solid electrolyte layer in the cylindrical container opposite to the electrode sheet, and then pressed and laminated to produce an all-solid-state battery (test cell). The cell was restrained with a special jig, and AC impedance measurements were performed.

[0086] <AC Impedance Measurement> The above cell, constrained with a dedicated jig, was charged to 3.6V at 0.1C. Then, AC impedance measurements were performed using the Solartron 1470E Cell test system from Solartron Analytical, and a Cole-Cole plot was obtained. From this, the interface resistance was estimated to be 16Ω.

[0087] (Example 6) A positive electrode sheet was prepared in the same manner as in Example 4, except that 0.0445 g of compound α, 0.0247 g of SBS solution, and 0.5 mL of anisole were used. The positive electrode sheet did not break or peel off from the Al foil when wrapped around a cylinder with a diameter of 16 mm. Furthermore, the positive electrode sheet could be punched out successfully. Furthermore, when the interfacial resistance was measured using this positive electrode sheet in the same manner as in Example 5, it was found to be 15Ω.

[0088] (Comparative Example 4) A positive electrode sheet was prepared in the same manner as in Example 4, except that 0.0495 g of compound α and 0.5 mL of anisole were used instead of SBS. The positive electrode sheet did not break or peel off from the Al foil when wrapped around a 16 mm diameter cylinder, and the positive electrode sheet could be punched out, but peeling was observed at the punched-out edges, indicating insufficient bonding. Furthermore, when the interfacial resistance was measured using this positive electrode sheet in the same manner as in Example 5, it was found to be 15Ω.

[0089] (Comparative Example 5) A positive electrode sheet was prepared using the method described in Example 4, except that compound α was not used, and 0.0495 g of SBS solution and 0.4 mL of anisole were used. The positive electrode sheet did not break or peel off from the Al foil when wrapped around a cylinder with a diameter of 16 mm, and the positive electrode sheet could be punched out, but peeling was observed at the punched-out edges, indicating insufficient bonding. Furthermore, when the interfacial resistance was measured using this positive electrode sheet in the same manner as in Example 5, it was found to be 34Ω.

[0090] Examples 4, 5, Comparative Examples 4, and 5 show that by using compound α and SBS in combination, it is possible to simultaneously improve the bonding properties of the electrode composite layer and reduce the cell interface resistance.

[0091] (Example 7) <Preparation of solid electrolyte sheets using a composite binder of compound α and cellulose ether> (1) Preparation of the coating solution A cellulose ether solution with a concentration of 20% by mass was prepared by dissolving cellulose ether (Etocell, manufactured by Nisshin Kasei Co., Ltd.) in anisole. To 0.1 g of this solution, 0.76 g of Li3PS4 solid electrolyte and 0.7 mL of anisole were added and stirred, and then 0.1 g of an anisole solution of compound α (concentration of 20% by mass) was added and dissolved. Next, the mixture was kneaded using a planetary stirring and defoaming apparatus (MAZERUSTAR KK-250S, manufactured by Kurabo Industries Ltd.) under the following kneading conditions. [Mixing conditions] Rotation: 1600 rpm Revolution: 1600 rpm Processing time: 180 seconds x 3

[0092] After mixing, the sample was treated in an ultrasonic cleaner for 5 minutes, and then mixed again under the same mixing conditions as described above. Next, 0.2 mL of anisole was added to the sample and kneaded further under the same kneading conditions as above to obtain a slurry-like resin composition (slurry solid content concentration 48% by mass).

[0093] (2) Preparation of solid electrolyte sheets The coating solution obtained in (1) above was applied to a 5cm x 10cm piece of aluminum foil to form a coating film. The coating film was then dried at 60°C for 10 hours to remove the solvent (anisole) and a solid electrolyte sheet was prepared. The resulting solid electrolyte sheet did not break or peel off from the Al foil when wrapped around a 16 mm diameter cylinder. This demonstrated that cellulose ether functions well as a binder even when used instead of SBS.

[0094] (Example 8) <Preparation of solid electrolyte sheets using a composite binder of compound α and polyethylene oxide> A 5% by mass polyethylene oxide solution was prepared by dissolving polyethylene oxide (PEO) (Sigma-Aldrich "Poly(ethylene oxide) average Mv 600,000") in anisole. To 0.24 g of this solution, 0.76 g of Li3PS4 solid electrolyte and 0.8 mL of anisole were added and stirred, and then 0.14 g of an anisole solution of compound α (concentration 20% by mass) was added and dissolved. A slurry-like resin composition was prepared in the same manner as in Example 7, except that no additional anisole was added (compound α:PEO = 70:30 "mass ratio"). The obtained resin composition could also be used to produce a solid electrolyte sheet in the same manner as in Example 7.

[0095] (Example 9) <Preparation of solid electrolyte sheets using a composite binder of compound α and polyethylene oxide> A polyethylene oxide solution with a concentration of 5% by mass was prepared by dissolving PEO in anisole. To 0.04 g of this solution, 0.76 g of Li3PS4 solid electrolyte and 0.6 mL of anisole were added and stirred, and then 0.19 g of an anisole solution of compound α (concentration 20% by mass) was added and dissolved. A slurry-like resin composition was prepared in the same manner as in Example 7, except that no additional anisole was added (compound α:PEO = 95:5 "mass ratio"). The obtained resin composition could also be used to produce a solid electrolyte sheet in the same manner as in Example 7.

[0096] Examples 8 and 9 showed that complexes using PEO instead of SBS also function as binders.

[0097] Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will find it easy to make many modifications to these exemplary embodiments and / or examples without substantially departing from the novel teachings and effects of the present invention. Accordingly, many of these modifications fall within the scope of the present invention. All references made in this specification and to the application on which the priority claim of this application under the Paris Convention rest with respect to this specification.

Claims

1. Two or more PS ４ ３－ Unit (PS ４ A battery binder comprising a resin composition containing a compound having a disulfide bond (S-S) in a P-S-S chain formed by the bonding of (structure) and a thermoplastic resin.

2. The aforementioned compound is PS ４ A battery binder according to claim 1, obtained by oxidizing a raw material compound containing the structure with an oxidizing agent.

3. The battery binder according to claim 1 or 2, wherein the compound comprises a disulfide bond formed by any of the following reaction formulas (1) to (3). 【Transformation 3】 (In the formula, X is a halogen, and n is an integer.)

4. The battery binder according to claim 3, wherein X in the above reaction formulas (1) to (3) is iodine (I), fluorine (F), chlorine (Cl), or bromine (Br).

5. The battery binder according to any one of claims 1 to 4, wherein the compound has a peak derived from a disulfide bond connecting two phosphorus elements in Raman spectroscopy.

6. The battery binder according to any one of claims 1 to 5, wherein the thermoplastic resin is one or more selected from the group consisting of styrene-butadiene thermoplastic elastomers, cellulose ethers, carboxymethylcellulose, fluororesins, polyethers, polyacrylonitrile, polyvinyl acetate, polymethyl methacrylate, polyphosphazene, polyvinylpyrrolidone, polyethylene oxide, polyacrylic acid, and polyamide-imide resins.

7. The battery binder according to any one of claims 1 to 6, wherein the compound comprises one or more elements selected from the group consisting of lithium, sodium, magnesium, and aluminum.

8. A battery binder according to any one of claims 1 to 7, further comprising a halogen.

9. The battery binder according to claim 8, wherein the halogen is iodine or bromine.

10. A battery electrode composite layer or electrolyte layer comprising a battery binder according to any one of claims 1 to 9.

11. The electrode composite layer or electrolyte layer for a battery according to claim 10, further comprising a solid electrolyte other than the aforementioned battery binder.

12. A battery sheet comprising one or more components selected from the group consisting of an electrode composite layer and an electrolyte layer for batteries as described in claim 10 or 11.

13. A battery comprising a battery binder according to any one of claims 1 to 9.

14. PS ４ Adding an oxidizing agent to a raw material compound containing a structure, and oxidizing the said raw material compound, A method for producing a battery binder, comprising mixing the compound obtained by the oxidation with a thermoplastic resin.

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