Compound and battery containing same

Abstract

One of the purposes of the present invention is to provide: a compound which can be used as a binder having ion conductivity; and a battery which contains the compound.　One aspect of the present invention is a compound which contains P and S as constituent elements and has both of a group containing at least one element that is bound to the P and is selected from the group consisting of O, N and a halogen and a disulfide bond.

Description

Compound and battery containing same

[0001] The present invention relates to a compound and a battery containing the same.

[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 referred to as an "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 describe the PS on the surface of an electrode active material. ４ In addition, Non-Patent Document 3 discloses the polymerization of 70Li ２ S-30P ２ S ５ The chemical structure change due to heat treatment is disclosed for the above.

[0004] Masato Sumita and two others, "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, p. 9698-9704 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, p. 4768-4774 Yuichi Hasegawa, 'Chemical structure analysis of sulfide-based solid electrolyte 70Li2S-30P2S5', [online], February 1, 2018, Toray Research Center, Inc., [searched July 9, 2019], Internet <URL: https: / / www.toray-research.co.jp / technical-info / trcnews / pdf / 201802-01.pdf>

[0005] It is conceivable to use polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), or the like as a binder. However, such binders have a problem in that the ionic conductivity decreases when the amount added is increased to obtain binding between the materials (e.g., electrode mixtures) that constitute the layer. Therefore, a compound that can function as a binder while having ionic conductivity is desired.

[0006] An object of the present invention is to provide a compound that can be used as an ionically conductive binder and a battery containing the same.

[0007] As a result of extensive research, the present inventors have found that a compound containing phosphorus and sulfur as constituent elements and having a disulfide bond can be used as an ion-conductive binder, and have completed the present invention. According to the present invention, the following compounds and the like can be provided: 1. A compound containing P and S as constituent elements, and having a group containing one or more elements selected from the group consisting of O, N, and halogen, bonded to the P, and a disulfide bond. 2. The compound according to 1, in which the group contains O. 3. The compound according to 1 or 2, in which Raman spectroscopy shows a peak derived from the disulfide bond connecting two P atoms. 4. ３１ In P-NMR measurement, PS ｘ O ｙ 4. The compound according to any one of 1 to 3, having a peak derived from the structure (where 1≦x and 0<y). ｘ O ｙ The peaks due to the structure are ３ 6. The compound according to any one of 1 to 5, which comprises a structure represented by the following formula (1): (In formula (1), X is any group.) 7. A compound according to any one of 1 to 6, comprising a structure represented by the following formula (1) and a structure represented by the following formula (7). (In formulas (1) and (7), X is any group, and multiple Xs may be the same or different.) 8. A compound according to any one of 1 to 7, containing one or more elements selected from the group consisting of Li, Na, Mg, and Al as constituent elements. 9. A compound according to any one of 1 to 8, obtained by adding an oxidizing agent to a raw material compound containing one or more elements selected from the group consisting of P and S, and O, N, and halogen as constituent elements, and then reacting the raw material compound with the oxidizing agent. 10. A compound according to any one of 1 to 9, containing a disulfide bond formed by the following reaction formula (9): (In the formula, R is a group containing one or more elements selected from the group consisting of O, N, and a halogen. X is a halogen.) 11. The compound according to 10, wherein X in reaction formula (9) is iodine (I), fluorine (F), chlorine (Cl), or bromine (Br). 12. A battery binder comprising the compound according to any one of 1 to 11. 13. The battery binder according to 12, which contains a halogen. 14. The battery binder according to 13, wherein the halogen is I or Br. 15. An electrode mixture layer or electrolyte layer for a battery, comprising the battery binder according to any one of 12 to 14. 16. The electrode mixture layer or electrolyte layer for a battery according to 15, further comprising a solid electrolyte. 17. A battery sheet, comprising one or more elements selected from the group consisting of the electrode mixture layer for a battery and the electrolyte layer according to 15 or 16. 18. A battery, comprising the compound according to any one of 1 to 11. 19. 20. A method for producing a compound, comprising: adding an oxidizing agent to a raw material compound containing, as constituent elements, P and S, and one or more elements selected from the group consisting of O, N, and halogens; and reacting the raw material compound with the oxidizing agent. 21. A method for producing a compound according to 19, wherein the raw material compound contains, as constituent elements, one or more elements selected from the group consisting of Li, Na, Mg, and Al. 22. A method for producing a compound according to 19, wherein the raw material compound is PS ｘ O ｙ 21. A method for producing the compound according to 19 or 20, which comprises the structure (wherein 1≦x and 0<y). 22. The PS ｘ O ｙ The structure is PS ３23. A method for producing a compound according to any one of 19 to 22, wherein the oxidizing agent is a simple halogen atom. 24. The simple halogen atom is I ２ or Br ２ 25. A method for producing a compound according to any one of 19 to 24, wherein the raw material compound and the oxidizing agent are reacted by one or more selected from the group consisting of physical energy, thermal energy, and chemical energy. 26. A method for producing a compound according to any one of 19 to 24, wherein the raw material compound and the oxidizing agent are reacted in a liquid.

[0008] According to the present invention, it is possible to provide a compound that can be used as an ion-conductive binder and a battery including the same.

[0009] 1 shows Raman spectra of the compounds obtained in Production Example 1 and Examples 1 to 4. 2 shows Raman spectra of the compounds obtained in Production Example 3 and Example 6. 3 shows Raman spectra of the compounds obtained in Example 7. 4 shows the results of powder X-ray analysis of the compounds obtained in Production Example 1 and Examples 1 to 4. 5 shows the results of powder X-ray analysis of the solids of the compounds obtained in Production Example 1 and Example 1. ３１ P-NMR spectrum of the compounds obtained in Examples 2 to 4. ３１ P-NMR spectrum of the compound obtained in Example 5. ３１ 1 is a P-NMR spectrum; FIG. 2 is a diagram showing the results of initial charge and discharge of the cells of Example 13 and Comparative Examples 6 and 7; FIG. 3 is a diagram showing the results of initial charge and discharge of the cell of Example 14; FIG. 4 is a Cole-Cole plot of the cells of Example 13 and Comparative Examples 6 and 7; FIG. 5 is a Cole-Cole plot of the cell of Example 14; FIG. 6 is a diagram showing the results of cycle characteristics of the cells of Example 13 and Comparative Examples 6 and 7; FIG. 7 is a diagram showing the results of cycle characteristics of the cell of Example 14; FIG. 8 is a Raman spectrum of the compounds obtained in Examples 15 and 16; FIG. 9 is a diagram showing the results of XPS measurement of Example 15; FIG. 10 is a diagram showing the results of XPS measurement of Example 16;

[0010] The compound, battery binder, battery electrode mixture layer, electrolyte layer, battery sheet, battery, and method for producing the compound of the present invention are described in detail below. In this specification, "x to y" represents a numerical range of "x or more and y or less." The upper and lower limits described for numerical ranges can be combined arbitrarily. A combination of two or more of the individual aspects of the present invention described below is also an aspect of the present invention.

[0011] <Compound α> A compound according to one embodiment of the present invention (also referred to as "compound α") contains P and S as constituent elements, and has a group (also referred to as "group R") bonded to the P and containing one or more elements selected from the group consisting of O, N, and halogen, and a disulfide bond.

[0012] Compound α has ionic conductivity and can be suitably used as a binder for batteries and the like. Compound α also exhibits excellent solubility. This is thought to be due to the fact that even if Compound α is polymerized, branching of the molecular chain is suppressed, thereby suppressing the formation of a three-dimensional network structure that causes a decrease in solubility.

[0013] The group R is not particularly limited as long as it contains one or more elements selected from the group consisting of O, N, and halogen, and examples thereof include -OM (M is a metal element), halogen, =NH, -N=Y, and -N(Z １ ) Z ２ (Y, Z, etc.) １ and Z ２ will be described later.) In -OM, examples of M include Li, Na, Mg, and Al. In one embodiment, the group R contains one or more elements selected from the group consisting of O and N. The group R preferably contains O. It is also preferable that the group R contains N. The group R may be single-bonded to P in the compound α, or multiple-bonded (for example, double or triple bonded).

[0014] In one embodiment, O, N, or halogen in the group R is directly bonded (eg, covalently bonded) to P in the compound α.

[0015] The compound α can have one or more groups R. When the compound α has two or more groups R, the two or more groups R may be the same or different.

[0016] In one embodiment, compound α has a peak derived from a disulfide bond connecting two P's in Raman spectroscopy.

[0017] In one embodiment, compound α has a Raman shift of 425 cm －１ More than 500cm －１ Below 440 cm, preferably －１ 490cm or more －１ Less than 460 cm, more preferably －１ 480cm or more －１ It has a peak (hereinafter also referred to as "Peak A") in the following range. Peak A is derived from a disulfide bond (S-S) that connects two Ps in compound α. Compound α may be identified as having a disulfide bond (S-S) by the presence of Peak A.

[0018] In one embodiment, compound α has a Raman shift of 370 cm －１ Over 425cm －１ Less than 380 cm －１ Over 423cm －１ Less than 390 cm, more preferably －１ More than 420cm －１ It has a peak (hereinafter also referred to as "peak B") in the following range. ｘ O ｙ Structure and / or PS ４ This is due to the symmetric stretching caused by the P--S bond in the structure.

[0019] Raman spectroscopy of compound α is performed by the method described in the Examples. It is important to perform the measurement after treating compound α with toluene. This is to remove elemental sulfur that may be present in compound α. Elemental sulfur has a peak at a position that may overlap with peak A. Therefore, removing elemental sulfur allows for good measurement of peak A derived from compound α. Toluene treatment is performed according to the procedure described in the Examples.

[0020] In one embodiment, compound α is ３１ In P-NMR measurement, PS ｘ O ｙ It has peaks derived from the structure (where 1≦x and 0<y). ｘ O ｙ The structure is not particularly limited. In one embodiment, PS ｘ O ｙ The structure is PS ３ O structure, PS ２ O ２ Structure and PSO ３ The structure is one or more selected from the group consisting of P ２ S ６ O structure (PS ３ O １／２ structure), P ２ S ５ O ２ Structure (PS ５／２ O), P ２ S ４ O ３ Structure (PS ２ O ３／２ structure), P ２ S ３ O ４ Structure (PS ３／２ O ２ Structure) and P ２ S ２ O ７ Structure (PSO ７／２ In one embodiment, PS ｘ O ｙ The structure is PS ３ It has an O structure. ３１ P-NMR measurement can be carried out by the method described in the Examples.

[0021] In one embodiment, compound α contains one or more structures selected from the group consisting of structures represented by the following formulas (1) to (5), thereby enabling the effects of the present invention to be more effectively exhibited.

[0022]

[0023] In formulas (1) to (3), X is an arbitrary group, for example, the above-mentioned metal element M. In formula (4), Y is an arbitrary group, for example, =PS２ In formula (5), Z １ and Z ２ are each an arbitrary group, which may be the same or different, for example, -PS ３ is.

[0024] The compound α preferably contains a structure represented by formula (1), which allows the effects of the present invention to be more effectively exhibited.

[0025] In one embodiment, the compound α includes a structure represented by the following formula (6): This allows the effects of the present invention to be more effectively exhibited.

[0026]

[0027] In formula (6), X is any group, for example, the above-mentioned metal element M. The two Xs may be the same or different.

[0028] In one embodiment, the compound α includes both a structure represented by formula (1) and a structure represented by the following formula (7):

[0029]

[0030] In formula (7), X is any group, for example, the metal element M described above.

[0031] In compound α, the structure represented by formula (1) may be included as the structure represented by formula (6). Furthermore, compound α may include the structure represented by formula (1) and the structure represented by formula (7). In this case, multiple Xs may be the same or different.

[0032] In one embodiment, the structure represented by formula (1) is contained as a repeating unit in compound α. In one embodiment, when compound α contains a structure represented by formula (7), the structure represented by formula (7) is contained as a repeating unit in compound α.

[0033] The fact that compound α contains the structures represented by formulas (1) to (7) can be confirmed by NMR and Raman measurements.

[0034] In one embodiment, compound α contains, as a constituent element, one or more elements selected from the group consisting of Li, Na, Mg, and Al. In one embodiment, these constituent elements are bonded to S in compound α by an ionic bond. Furthermore, when compound α contains O, these constituent elements are bonded to O by an ionic bond to form -OM, which is an example of the group R described above.

[0035] <Battery Binder> A battery binder according to one embodiment of the present invention (hereinafter referred to as battery binder (A)) contains the above-described compound α. The battery binder (A) may further contain a halogen. The halogen may be derived from an oxidizing agent or the like used in producing compound α. The halogen may be one or more selected from the group consisting of I, F, Cl, and Br. The halogen may be I or Br.

[0036] The form of the halogen 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 Li, Na, Mg, and Al, or one or more elements selected from the group consisting of simple halogens. Examples of the salt include LiI, NaI, and MgI. ２ , AlI ３ , LiBr, NaBr, MgBr ２ , AlBr ３ Among these, LiI and LiBr are preferred from the viewpoint of ionic conductivity. ２ , F ２ , Cl ２ ,Br ２ Among these, from the viewpoint of reducing corrosion when it remains in the binder (A), I ２ ,Br ２ In one embodiment, the battery binder (A) may have higher ionic conductivity by containing a halogen as the above-described salt.

[0037] In one embodiment, the battery binder (A) further contains one or more selected from the group consisting of orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphorous acid, and salts thereof.

[0038] The content of the compound α in the battery binder (A) is not particularly limited, and for example, from the viewpoint of the binding strength of the active material and the solid electrolyte described below, the content is 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 98% by mass or more, 99% by mass or more, 99.5% by mass or more, 99.8% by mass or more, or 99.9% by mass or more, when the total mass of the battery binder (A) is taken as 100% by mass.

[0039] The content of the halogen-containing substance (elemental halogen and halogen compounds; however, halogen compounds corresponding to compound α are not included in the halogen-containing substance) in the battery binder (A) is not particularly limited, and for example, from the viewpoint of the conductivity of the carrier ions and the binding strength of the active material and the solid electrolyte, 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, when the total mass of the battery binder (A) is taken as 100% by mass. The total content of orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphorous acid, and salts thereof in the battery binder (A) is not particularly limited. The battery binder (A) may be substantially 100 mass % of the compound α, or may be one or more substances selected from the group consisting of the compound α and one or more substances selected from the group consisting of a halogen-containing substance, orthophosphoric acid, pyrophosphoric acid, metaphosphoric acid, phosphorous acid, and salts thereof.

[0040] The battery binder (A) can be used in various batteries. Examples of the battery include secondary batteries such as lithium-ion batteries. The battery can also be an all-solid-state battery. In such a battery, the "binder" is blended into one or more components, such as a battery electrode mixture layer and an electrolyte layer, and can exert binding properties (binding force) to bind other components contained in the component (e.g., layer) together and maintain the unity.

[0041] Conventional battery electrode mixture layers (e.g., positive electrodes or negative electrodes, as described below) have difficulty keeping up with the expansion and contraction (volume change) of electrode active materials accompanying charge and discharge, etc., and are prone to problems such as capacity degradation. The electrolyte layer adjacent to the battery electrode mixture layer may also be affected by the volume change of the battery electrode mixture layer, potentially causing problems such as degradation. In contrast, by using the battery binder (A), the battery electrode mixture layer or electrolyte layer can absorb volume changes due to the flexibility of the battery binder (A), preventing capacity degradation and the like. This allows the battery to exhibit excellent cycle characteristics. Furthermore, because the battery binder (A) itself can have ionic conductivity, even if the amount of the battery binder (A) added is increased to improve the binding between the materials (e.g., electrode mixtures) that make up the layer, a decrease in ionic conductivity can be suppressed, and the battery characteristics can be exhibited favorably. Furthermore, in one embodiment, the battery binder (A) has superior heat resistance compared to ordinary organic binders and polymer solid electrolytes (for example, polyethylene oxide, etc.), and therefore the operating temperature range of the battery can be expanded.

[0042] <Battery Electrode Mixture Layer or Electrolyte Layer> A battery electrode mix layer or electrolyte layer according to one embodiment of the present invention contains the battery binder (A) described above. In one embodiment, the battery binder (A) is unevenly distributed or uniformly distributed (dispersed) within the battery electrode mix layer or electrolyte layer. In one embodiment, the battery binder (A) is uniformly distributed (dispersed) within the layer, thereby better maintaining the integrity of the layer.

[0043] The battery electrode mixture layer or the electrolyte layer preferably further contains a solid electrolyte (hereinafter referred to as solid electrolyte (B)). The "solid electrolyte (B)" does not include the battery binder (A). The solid electrolyte (B) is not particularly limited, and for example, an oxide solid electrolyte or a sulfide solid electrolyte can be used. Among them, a sulfide solid electrolyte is preferred, and specifically, an argyrodite-type crystal structure, Li ３ P.S. ４ Crystal structure, Li ４ P ２ S ６ Crystal structure, Li ７ P ３ S１１ Crystal structure, Li ４－ｘ Ge １－ｘ P ｘ S ４ Thio-LISICON Region II crystal structure, Li ４－ｘ Ge １－ｘ P ｘ S ４ Examples of suitable sulfide solid electrolytes include those having a crystal structure similar to a thio-LISICON Region II type (hereinafter sometimes abbreviated as an RII type crystal structure).

[0044] The solid electrolyte (B) may or may not contain a compound in which all of the groups R in the compound α are replaced by -SM (M is a metal element, and the explanation given for the compound α is also incorporated herein by reference) (also referred to as "compound α'"). Furthermore, the solid electrolyte (B) may or may not contain an organic binder.

[0045] Examples of the electrode mixture layer for a battery include a positive electrode and a negative electrode. When the electrode mixture layer for a battery is a positive electrode, the positive electrode may further include a positive electrode active material. The positive electrode active material is a material capable of inserting and extracting lithium ions, and any material known in the field of batteries as a positive electrode active material can be used.

[0046] Examples of the positive electrode active material include metal oxides and sulfides. Sulfides include metal sulfides and non-metal sulfides. Metal oxides include, for example, transition metal oxides. Specifically, V ２ O ５ , V ６ O １３ , LiCoO ２ , LiNiO ２ , LiMnO ２ , LiMn ２ O ４ , Li(Ni ａ Co ｂ Mn ｃ ) O ２ (Here, 0<a<1, 0<b<1, 0<c<1, a+b+c=1), LiNi １－Ｙ Co Ｙ O ２ , LiCo１－Ｙ Mn Ｙ O ２ , LiNi １－Ｙ Mn Ｙ O ２ (where 0≦Y<1), Li(Ni ａ Co ｂ Mn ｃ ) O ４ (0<a<2, 0<b<2, 0<c<2, a+b+c=2), LiMn ２－Ｚ Ni Ｚ O ４ , LiMn ２－Ｚ Co Ｚ O ４ (where 0<Z<2), LiCoPO ４ , LiFePO ４ , CuO, Li(Ni ａ Co ｂ Al ｃ ) O ２ (where 0<a<1, 0<b<1, 0<c<1, a+b+c=1) and the like. Examples of metal sulfides include titanium sulfide (TiS ２ ), molybdenum sulfide (MoS ２ ), iron sulfide (FeS, FeS ２ ), copper sulfide (CuS) and nickel sulfide (Ni ３ S ２ Other examples of metal oxides include bismuth oxide (Bi ２ O ３ ), bismuth lead oxide (Bi ２ Pb ２ O ５ ) and the like. Examples of non-metal sulfides include organic disulfide compounds, carbon sulfide compounds, and the like. In addition to the above, niobium selenide (NbSe ３ ), metallic indium, and sulfur can also be used as the positive electrode active material.

[0047] When the battery electrode mixture layer is a negative electrode, the negative electrode may further include a negative electrode active material. The negative electrode active material may be a material typically used in lithium-ion secondary batteries, such as a carbon material such as graphite, natural graphite, artificial graphite, hard carbon, or soft carbon; a composite metal oxide such as a polyacene-based conductive polymer or lithium titanate; or a compound that forms an alloy with lithium, such as silicon, a silicon alloy, a silicon composite oxide, tin, or a tin alloy. Among these, the negative electrode active material preferably includes at least one selected from the group consisting of Si (silicon, silicon alloy, silicon-graphite composite, silicon composite oxide, etc.) and Sn (tin, tin alloy).

[0048] One or both of the positive electrode and the negative electrode may contain a conductive additive. When the electronic conductivity of the active material is low, it is preferable to add a conductive additive. This can improve the rate characteristics of the battery.

[0049] Specific examples of conductive additives include carbon materials, nickel, copper, aluminum, indium, silver, cobalt, magnesium, lithium, chromium, gold, ruthenium, platinum, beryllium, iridium, molybdenum, niobium, osmium, rhodium, tungsten, and zinc, and more preferably, highly conductive carbon, carbon materials other than carbon, and metal elements, mixtures, or compounds containing nickel, copper, silver, cobalt, magnesium, lithium, ruthenium, gold, platinum, niobium, osmium, or rhodium. Specific examples of carbon materials include carbon blacks such as ketjen black, acetylene black, denka black, thermal black, and channel black; graphite, carbon fiber, and activated carbon, which can be used alone or in combination of two or more. Among these, acetylene black and ketjen black, including denka black, which have high electronic conductivity, are preferred.

[0050] The electrolyte layer contains a battery binder (A) and may contain, as an optional component, a solid electrolyte (B) other than the battery binder (A).

[0051] The composition of the positive electrode is not particularly limited, and may be, for example, a mass ratio of positive electrode active material: solid electrolyte (B): battery binder (A): conductive additive = 50 to 99: 0 to 30: 1 to 30: 0 to 30. 30 mass% or more, 50 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more of the positive electrode may be the positive electrode active material, solid electrolyte (B), battery binder (A), and conductive additive.

[0052] The composition of the negative electrode is not particularly limited, and may be, for example, a mass ratio of negative electrode active material: solid electrolyte (B): battery binder (A): conductive additive = 40 to 99: 0 to 30: 1 to 30: 0 to 30. 30 mass% or more, 50 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, or 99 mass% or more of the negative electrode may be the negative electrode active material, solid electrolyte (B), battery binder (A), and conductive additive.

[0053] The composition of the electrolyte layer is not particularly limited, and may be, for example, a mass ratio of solid electrolyte (B):battery binder (A) = 99.9:0.1 to 0:100. When the mass ratio of solid electrolyte (B) is 0, the battery binder (A) can also serve as a solid electrolyte. 30 mass% or more, 50 mass% or more, 80 mass% or more, 90 mass% or more, 95 mass% or more, 98 mass% or more, 99 mass% or more, or 99.9 mass% or more of the electrolyte layer may be solid electrolyte (B) and battery binder (A).

[0054] The method for forming a layer containing compound α, for example, the method for forming each layer constituting the above-described battery, is not particularly limited, and examples thereof include coating methods. In coating methods, a coating solution in which the components contained in each layer are dissolved or dispersed in a solvent can be used. Examples of solvents that can be used in the coating solution include linear, 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, and acetonitrile. A layer (dried coating film) is formed by drying the solvent after coating. Anisole is preferred from the viewpoint of ease of drying the solvent. The drying method is not particularly limited, and for example, one or more means selected from the group consisting of heat drying, air drying, and reduced-pressure drying (including vacuum drying) can be used.

[0055] The compound α according to this embodiment has excellent solubility, and therefore has improved dispersibility and stretchability, making it possible to preferably apply the coating method described above, to use various solvents with high versatility, and to improve the binding property of the formed layer.

[0056] The member to which the coating liquid is applied is not particularly limited. The formed layer may be used in a battery together with the member, or the formed layer may be peeled off from the member and used in a battery. In one embodiment, the coating liquid for forming a positive electrode is applied onto a positive electrode current collector. In one embodiment, the coating liquid for forming a negative electrode is applied onto a negative electrode current collector. In one embodiment, the coating liquid for forming an electrolyte layer is applied onto a positive electrode or a negative electrode. In one embodiment, the coating liquid for forming an electrolyte layer is applied onto an easily peelable member, and then the formed layer is peeled off from the easily peelable member and placed between the positive electrode and the negative electrode.

[0057] It is preferable to press the dried coating film (layer). The pressing may be any method that compresses the layer by pressing. For example, pressing can be performed so as to reduce the porosity in 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 about room temperature (23°C), or may be lower or higher than room temperature. By pressing, the battery binder (A) contained in the layer is suitably deformed due to its flexibility, and interface formation between the electrode mixtures contained in the layer is promoted. This further improves the battery characteristics.

[0058] The pressing may be performed on each layer, or on a stack of multiple layers (for example, a "battery sheet" described later) so as to press the multiple layers in the stacking direction.

[0059] <Battery Sheet> A battery sheet according to one embodiment of the present invention includes at least one layer selected from the group consisting of the electrode mixture layer and the electrolyte layer described above. By including the compound α or the battery binder (A), the battery sheet exhibits excellent flexibility and is prevented from breaking or peeling from the current collector.

[0060] <Battery> A battery according to one embodiment of the present invention contains the compound α described above. In one embodiment, the battery is an all-solid-state battery. In one embodiment, the all-solid-state battery includes a laminate including, in this order, a positive electrode current collector, a positive electrode, an electrolyte layer, a negative electrode, and a negative electrode current collector. The current collector can be a plate or foil made of copper, magnesium, stainless steel, titanium, iron, cobalt, nickel, zinc, aluminum, germanium, indium, lithium, or an alloy thereof. In the battery, it is preferable that one or more selected from the group consisting of the positive electrode, the electrolyte layer, and the negative electrode contain the compound α.

[0061] In the above description (and in the examples described later), the use of compound α in a battery has been mainly described, but the present invention is not limited thereto. Compound α has excellent flexibility, ionic conductivity, and the like, and therefore can be widely used in a variety of applications.

[0062] <Method for Producing Compound α> A method for producing compound α according to one aspect of the present invention includes adding an oxidizing agent to a raw material compound containing P, S, and O as constituent elements, and reacting the raw material compound with the oxidizing agent. By reacting the raw material compound with the oxidizing agent, the above-described compound α is obtained as a product. In one embodiment, compound α is obtained by adding an oxidizing agent to a raw material compound containing P and S as constituent elements, and one or more elements selected from the group consisting of O, N, and halogens, and then reacting the raw material compound with the oxidizing agent.

[0063] The raw material compound (hereinafter referred to as "raw material compound (C)") contains, as constituent elements, P and S, and one or more elements selected from the group consisting of O, N, and halogens. The raw material compound (C) preferably contains, as constituent elements, one or more elements selected from the group consisting of Li, Na, Mg, and Al. The raw material compound (C) is PS ｘ O ｙ Preferably, the structure is: (where 1≦x and 0<y). In one embodiment, the structure is: ｘ O ｙ The structure is PS ３ O structure, PS ２ O ２ Structure, PSO ３ The structure is one or more selected from the group consisting of P ２ S ６ O structure (PS ３ O １／２ structure), P ２ S ５ O ２ Structure (PS ５／２ O), P ２ S ４ O ３ Structure (PS ２ O ３／２ structure), P ２ S ３ O ４ Structure (PS ３／２ O ２ Structure) and P ２ S ２ O ７ Structure (PSO ７／２ In one embodiment, PS ｘ Oｙ The structure is PS ３ O structure. PS ３ As the raw material compound (C) containing an O structure, for example, Li ３ P.S. ３ O, Na ３ P.S. ３ O, Mg ３／２ P.S. ３ O, etc. ３ P.S. ３ O is, for example, Li ２ O, Li ２ S and P ２ S ５ can be produced by reacting the above in the presence of a dispersion medium by a mechanochemical method (mechanical milling).

[0064] In one embodiment, Li ２ O, Li ２ S and P ２ S ５ and an oxidizing agent in the presence of a dispersion medium (such as n-heptane) by mechanochemical method (mechanical milling), thereby producing the compound α.

[0065] As the raw material compound (C), one type may be used alone, or two or more types may be used in combination.

[0066] A raw material compound (also referred to as "raw material compound (C')") containing P and S as constituent elements but not O may be used together with the raw material compound (C). In this case, an oxidizing agent can be added to a mixture of the raw material compound (C) and the raw material compound (C'), and the raw material compound (C) and the raw material compound (C') in the mixture can be reacted with the oxidizing agent. The raw material compound (C') preferably contains one or more elements selected from the group consisting of Li, Na, Mg, and Al as constituent elements. In one embodiment, the raw material compound (C') is PS ４ Contains the structure: PS ４ As the raw material compound (C') containing the structure, for example, Li ３ P.S. ４ , Li ４ P ２ S ７、 Na ３ P.S. ４ , Na４ P ２ S ７ The raw material compound (C) is Li ４ P ２ S ７ , Na ４ P ２ S ７ etc., two or more PS ４ Here, the raw material compound (C′) may contain two adjacent PS ４ When the structure is contained, the two PS ４ The structures may share one S. ３ P.S. ４ For example, Li ２ S and P ２ S ５ and (C') in the presence of a dispersion medium by a mechanochemical method (mechanical milling). Examples of the dispersion medium include n-heptane. As the raw material compound (C'), one compound may be used alone, or two or more compounds may be used in combination.

[0067] In one embodiment, the compound α can be produced by reacting the raw material compound (C), the raw material compound (C′), and an oxidizing agent in the presence of a dispersion medium by a mechanochemical method (mechanical milling). Here, a part or all of the raw material compound (C) is oxidized with a raw material of the raw material compound (C), for example, Li ２ O, Li ２ S and P ２ S ５ In addition, a part or all of the raw material compound (C') may be replaced with a raw material for the raw material compound (C') (for example, Li ２ S and P ２ S ５ ) may be substituted.

[0068] In the above description, Li ２ For example, Na instead of S ２ S, etc. may also be used. ２ Instead of O, for example, Na ２ O, etc. may also be used. For the mechanochemical method, for example, a planetary ball mill, etc. may be used. As the dispersion medium, for example, n-heptane, etc. may be used.

[0069] Examples of oxidizing agents include halogens, oxygen, ozone, and oxides (Fe ２ O ３ , MnO ２ , Cu ２ O, Ag ２ O, etc.), oxoacid salts (chlorate, hypochlorite, iodate, bromate, chromate, permanganate, vanadate, bismuthate, etc.), peroxides (lithium peroxide, sodium peroxide, etc.), halide salts (AgI, CuI, PbI ２ , AgBr, CuCl, etc.), cyanide salts (AgCN, etc.), thiocyanates (AgSCN, etc.), and sulfoxides (dimethyl sulfoxide, etc.). In one embodiment, the oxidizing agent is preferably a simple halogen, from the viewpoint of increasing ionic conductivity by the metal halide generated as a by-product. The "metal halide" may be a salt of a halogen with one or more elements selected from the group consisting of Li, Na, Mg, and Al derived from the raw material compound (C) (for example, lithium halide when the raw material compound (C) contains Li). Examples of simple halogens include I, ２ , F ２ , Cl ２ and Br ２ From the viewpoint that halogen element can obtain higher ionic conductivity, I ２ ,Br ２ As the oxidizing agent, one type may be used alone, or two or more types may be used in combination.

[0070] The present inventors have previously investigated the raw material compound (C') (e.g., Li ３ P.S. ４ ) and an oxidizing agent (e.g., I ２ The inventors have found that the above-mentioned compound α′ can be obtained by reacting the compound α′ with the compound α′. This reaction can be represented by the following reaction formula (8).

[0071]

[0072] The reaction represented by reaction formula (8) forms a crosslink of P-S-S-P disulfide bonds. In particular, extending this crosslink (a P-S-S chain consisting of repeating units of P-S-S) exhibits favorable binder properties. By incorporating the compound α' thus obtained into a solid electrolyte, a self-supporting solid electrolyte sheet can be produced. It has been confirmed that this solid electrolyte sheet, when equipped with positive and negative electrode materials, functions as a battery.

[0073] Generally, a battery binder is prepared by dissolving and dispersing a compound in a solvent to prepare a dispersion, and then mixing the dispersion with a slurry containing an active material, a solid electrolyte, and a conductive additive. Therefore, solubility is one of the important physical properties for a compound used as a battery binder. The compound α' described above is a compound containing PS ４ Because the structure contains three crosslinkable sulfur (S) single bonds, when polymerized (extending the P-S-S chain), the disulfide bonds branch, forming a three-dimensional network structure (not shown in reaction formula (8)). This three-dimensional network structure can reduce the solubility in solvents.

[0074] Therefore, the present inventors have conducted further intensive studies and found that by using starting compound (C) in place of part or all of starting compound (C'), branching of disulfide bonds (formation of a three-dimensional network structure) can be suppressed even when the P-S-S chain is extended, and compound α can be produced as a more linear, preferably straight-chain, multimer. Such a reaction can be represented, for example, by the following reaction formula (9).

[0075]

[0076] (wherein R is a group containing one or more elements selected from the group consisting of O, N, and halogen (which may correspond to the group R described above); and X is halogen.)

[0077] In reaction formula (9), the raw material compound (C) is a PS in the raw material compound (C'). ４ The structure is shown with the sulfur (S) replaced with another group R. For example, the starting compound (C) (e.g., Li ３ P.S. ３ O) and an oxidizing agent (e.g., I ２), the group R is —OLi.

[0078] In one embodiment, compound α contains a disulfide bond formed by reaction formula (9).

[0079] In one embodiment, X in Reaction Scheme (9) is iodine (I), fluorine (F), chlorine (Cl), or bromine (Br). In one embodiment, X in Reaction Scheme (9) is iodine (I).

[0080] In one embodiment, the raw material compound (C) is Li ３ P.S. ３ O, and the oxidizing agent is a simple halogen (X ２ ), the reactions shown in the following reaction formulas (10) to (12) proceed. In one embodiment, compound α has a P-S-S chain (a chain formed by repeating repeating units of P-S-S) (reaction formulas (10) and (11)). In one embodiment, the formation of branches (branching) accompanying the elongation of the P-S-S chain of compound α is prevented (reaction formula (12)). In one embodiment, two phosphorus atoms and a disulfide bond connecting these two phosphorus atoms constitute the P-S-S chain. (wherein X is a halogen and n is an integer.)

[0081] In one embodiment, compound α contains a disulfide bond formed by any of reaction formulas (10) to (12).

[0082] In one embodiment, X in Reaction Schemes (10) to (12) is iodine (I), fluorine (F), chlorine (Cl), or bromine (Br). In one embodiment, X in Reaction Schemes (10) to (12) is iodine (I).

[0083] Li to be reacted (blended) ３ P.S. ３ O and I ２ The molar ratio of ３ P.S. ３ O:I ２ ) 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 7:8.２ The larger the ratio of Li, the longer the P-S-S chain can be extended. ３ P.S. ３ O and I ２ This is not limited to the case where the reaction is carried out with, for example, PS ３ PS like O structure ｘ O ｙ This can also be applied to the case where a raw material compound (C) containing the structure (where 0≦x and 0<y) is reacted with a halogen element. In addition, when the raw material compound (C) and the raw material compound (C') are used in combination, the above molar ratio relationship can be applied by replacing it with the molar ratio of the total of the raw material compound (C) and the raw material compound (C') to the halogen element. Furthermore, the above molar ratio relationship can be applied when the raw material (e.g., Li ２ O, Li ２ S and P ２ S ５ ) is used, the amount of raw material compound (C) produced when these raw materials are completely reacted can be applied based on the amount of raw material compound (C). Similarly, the above molar ratio relationship can be applied based on the amount of raw material compound (C') (e.g., Li ２ S and P ２ S ５ ) can also be applied based on the amount of raw material compound (C') produced when these raw materials are completely reacted.

[0084] In the step of reacting the raw material compound (C) with the oxidizing agent (reaction step), the raw material compound (C) and the oxidizing agent are preferably reacted with one or more energies selected from the group consisting of physical energy, thermal energy, and chemical energy. In the reaction step, the raw material compound (C) and the oxidizing agent are preferably reacted with energy including physical energy. The physical energy can be supplied, for example, by using a mechanochemical method (mechanical milling). For example, a planetary ball mill or the like can be used for the mechanochemical method. In the mechanochemical method using a planetary ball mill or the like, the treatment conditions are not particularly limited, and for example, the rotation speed can be 100 rpm to 700 rpm, the treatment time can be 1 hour to 100 hours, and the ball diameter can be 1 mm to 10 mm.

[0085] In the reaction step, it is preferable to react the raw material compound (C) and the oxidizing agent in a liquid. In this case, the raw material compound (C) and the oxidizing agent can be reacted in the presence of a dispersion medium. Reacting the raw material 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 by mechanical energy. Examples of the dispersion medium include aprotic liquids. The aprotic liquid is not particularly limited, and examples include 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.

[0086] In one embodiment, when reacting the raw material compound (C) and the oxidizing agent in a liquid, the raw material compound (C) and / or the oxidizing agent can be reacted in a mixed state with a solvent. As the solvent, any of the dispersion media described above that can dissolve the raw material compound (C) and / or the oxidizing agent can be used. For example, anisole, dibutyl ether, etc. are suitable. Even in such a solution, the raw material 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, ultrasonic vibration, etc., thermal energy, and chemical energy. For example, when thermal energy is used, the solution can be heated. The heating temperature is not particularly limited and can be, for example, 40 to 200°C, 50 to 120°C, or 60 to 100°C.

[0087] In the reaction step, the compound α can be produced by oxidizing the raw material compound (C) with an oxidizing agent.

[0088] The above explanation applies not only to the case where the raw material compound (C) is used alone, but also to the case where the raw material compound (C) and the raw material compound (C') are used in combination.

[0089] When compound α is produced by a reaction in a 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 for removing the liquid is not particularly limited, and examples thereof include drying and solid-liquid separation, and two or more of these may be combined. When solid-liquid separation is used, compound α may be reprecipitated. In this case, compound α can be recovered as a solid (solid phase) by adding a 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, in which n-heptane is added as a poor solvent to an anisole solution containing compound α, followed by solid-liquid separation. The solid-liquid separation means is not particularly limited, and examples thereof include evaporation, filtration, and centrifugation. When solid-liquid separation is used, the effect of improving purity can be obtained.

[0090] In one embodiment, LiI is by-produced in association with the production 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 can have higher ionic conductivity. Here, the crystalline phase of LiI can be, for example, c-LiI (cubic crystal) (ICSD 414244) or h-LiI (hexagonal crystal) (ICSD 414242). Typically, when compound α is produced using a mechanochemical method (mechanical milling), c-LiI (cubic crystal) is obtained, and when a method involving reaction in liquid (preferably in solution) is used, h-LiI (hexagonal crystal) is obtained. The crystalline phase of LiI can be determined by powder X-ray diffraction or solid ７ This can be determined by Li-NMR measurement. ７ In the Li-NMR measurement, if a peak attributable to LiI (chemical shift -4.57 ppm) is observed, it is determined to be c-LiI, and if no peak attributable to LiI is observed, it is determined to be h-LiI.

[0091] Examples of the present invention will be described below, but the present invention is not limited to these examples.

[0092] 1. Preparation of Compound (Preparation Example 1) Li ２O (manufactured by Kojundo Kagaku Co., Ltd., 2Nup powder), Li ２ S (Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh) and P ２ S ５ (Merck) with Li ２ O: Li ２ S:P ２ S ５ The mixture was mixed in a molar ratio of 50:25:25 and reacted by mechanical milling under the following conditions: ３ P.S. ３ [Mechanical milling conditions] Planetary ball mill: Premium Line PL-7 manufactured by Fritsch GmbH Sample mass: 3.6 g Method: Wet milling (dispersion medium: n-heptane 11.7 mL) Ball: material: ZrO ２ , diameter 5 mm, total mass 106 g Pot: material ZrO ２ , volume 80 mL Rotation: 500 rpm Processing time: 20 hours

[0093] (Production Example 2) Li ２ S (Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh) and P ２ S ５ (Merck) with Li ２ S:P ２ S ５ The mixture was mixed at a molar ratio of 3:1 and reacted by mechanical milling in the same manner as in Production Example 1. Then, the dispersion medium was removed by drying, and Li ３ P.S. ４ (glass powder) was obtained.

[0094] (Production Example 3) Li ２ O (manufactured by Kojundo Kagaku Co., Ltd., 2Nup powder), Li ２ S (Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh) and P ２ S ５ (Merck) with Li ２ O: Li ２ S:P ２ S ５ The mixture was mixed in a molar ratio of 25:50:25 and reacted by mechanical milling in the same manner as in Production Example 1. Then, the dispersion medium was removed by drying, and Li ３ P.S.７／２ O １／２ (glass powder) was obtained.

[0095] (Example 1) Li obtained in Production Example 1 ３ P.S. ３ O to I ２ (manufactured by Kojundo Chemical Co., Ltd., 5N irregular grains; used after pulverization in a mortar) ３ P.S. ３ O:I ２ The mixture was added at a molar ratio of 2:1 and reacted by mechanical milling under the following conditions (polysulfurization). Then, the dispersion medium was removed by drying, and the compound (powder; based on the raw material composition, "Li ３ P.S. ３ O-I ２ (2:1) was obtained. [Mechanical milling conditions] Planetary ball mill: Premium Line PL-7 manufactured by Fritsch Corporation Sample mass: 1 g Type: Wet milling (n-heptane: 3 mL) Ball: Material: ZrO ２ , diameter 5 mm, total mass 53 g Pot: material ZrO ２ , volume 45 mL Rotation: 500 rpm Processing time: 20 hours

[0096] (Example 2) Molar ratio of Li ３ P.S. ３ O:I ２ The compound (based on the raw material composition, "Li ３ P.S. ３ O-I ２ (4:3)).

[0097] (Example 3) Molar ratio of Li ３ P.S. ３ O:I ２ The compound (based on the raw material composition, "Li ３ P.S. ３ O-I ２ (sometimes referred to as "(1:1)").

[0098] (Example 4) Molar ratio of Li ３ P.S. ３ O:I ２The compound (based on the raw material composition, "Li ３ P.S. ３ O-I ２ (4:5)).

[0099] (Example 5) Li obtained in Production Example 1 ３ P.S. ３ O and I ２ And, Li ３ P.S. ３ O:I ２ The compound was added to anisole at a molar ratio of 1:1 and reacted at 60°C for 3 days with stirring (polysulfurization; liquid phase synthesis). Then, the anisole was removed by drying, and the compound ("Li ３ P.S. ３ O-I ２ (1:1) Liq).

[0100] (Example 6) Li obtained in Production Example 3 ３ P.S. ７／２ O １／２ To I ２ (manufactured by Kojundo Chemical Co., Ltd., 5N irregular grains; used after pulverization in a mortar) ３ P.S. ７／２ O １／２ :I ２ The mixture was added at a molar ratio of 1:1 and reacted by mechanical milling in the same manner as in Example 1 (polysulfurization). Then, the dispersion medium was removed by drying, and the compound (powder; based on the raw material composition, "Li ３ P.S. ７／２ O １／２ -I ２ (sometimes referred to as "(1:1)").

[0101] (Example 7) Li obtained in Production Example 2 ３ P.S. ４ and Li obtained in Production Example 1 ３ P.S. ３ O, Li ３ P.S. ４ :Li ３ P.S. ３ The mixture was mixed in a molar ratio of 0:50 to obtain a mixture. ２ Li３ P.S. ４ +Li ３ P.S. ３ O:I ２ The mixture was added at a molar ratio of 1:1 and reacted by mechanical milling in the same manner as in Example 1 (polysulfurization). Then, the dispersion medium was removed by drying, and the compound ("Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２ (sometimes referred to as "(1:1)").

[0102] (Comparative Examples 1 to 3) Li obtained in Production Example 1 ３ P.S. ３ Li obtained in Production Example 2 instead of O ３ P.S. ４ Compounds were obtained in the same manner as in Examples 1 to 3, except that the compound obtained in Comparative Example 1 was prepared using Li ３ P.S. ４ -I ２ (2:1), the compound obtained in Comparative Example 2 was treated with Li ３ P.S. ４ -I ２ (4:3), the compound obtained in Comparative Example 3 was treated with Li ３ P.S. ４ -I ２ This is sometimes referred to as (1:1).

[0103] Evaluation (1) Raman Spectroscopic Analysis The compound (Li) obtained in Production Example 1 ３ P.S. ３ O), the compound obtained in Production Example 3 (Li ３ P.S. ７／２ O １／２) and the compounds obtained in Examples 1 to 4, 6, and 7 were subjected to the following toluene treatment, and then microscopic Raman spectroscopy was performed using a laser Raman spectrophotometer (Horiba, Ltd., LabRAM HR Evolution LabSpec 6). [Procedure for Toluene Treatment] a. 1 g of compound was placed in a vial, and 10 mL of toluene (Fujifilm Wako Pure Chemical Industries, Ltd., ultra-dehydrated) was added, stirred, and allowed to stand. b. After removing the supernatant, 10 mL of toluene was added again to the solid content (precipitate), stirred, and allowed to stand. c. The operation described in b above was repeated once. d. After removing the supernatant, the solid content (precipitate) was vacuum-dried at 60°C for 10 hours to obtain a toluene-treated compound.

[0104] The Raman spectra obtained by microscopic Raman spectroscopy are shown in Figure 1 (compounds of Production Example 1 and Examples 1 to 4), Figure 2 (compounds of Production Example 3 and Example 6), and Figure 3 (compound of Example 7). As shown in Figures 1 to 3, the compounds of Examples 1 to 4, 6, and 7 exhibited a Raman shift of 477 cm originating from the disulfide (S—S) bond of the P—S—S chain. －１ As can be seen from FIG. 1 in particular, the peak in the vicinity of the raw material I ２ With the increase in the P—S bond peak (peak B) shifts to the lower wavenumber side (Raman shift 422 cm －１ From 392 cm －１ From this, it is presumed that the P—S bond is elongated by the formation of a P—S—S chain in the compound.

[0105] (2) Powder X-ray analysis (XRD) The compound obtained in Production Example 1 (Li ３ P.S. ３ XRD was performed on the compound of Example 1 (LiI) and the compounds obtained in Examples 1 to 4. The results are shown in FIG. 4. In FIG. 4, dots are added to the peaks due to LiI. ３ P.S. ３ O-I ２ It can be seen that the compound (2:1) is amorphous, including the compound and LiI, which is a by-product of the reaction (polysulfurization). ２ In Examples 2 to 4 (Li３ P.S. ３ O-I ２ In the cases of (4:3), (1:1) and (4:5), precipitation of c-LiI (cubic crystal) was confirmed.

[0106] (3) ３１ P-NMR Measurement of the Compound (Li ３ P.S. ３ O) and the compounds obtained in Examples 1 to 5 were subjected to solid phase analysis using the following apparatus and conditions. ３１ P-NMR measurement was performed. Apparatus: ECZ400R apparatus (manufactured by JEOL Ltd.) Observation nuclei: ３１ P Observation frequency: 161.944 MHz Measurement temperature: room temperature Pulse sequence: single pulse (using 90° pulse) 90° pulse width: 3.2 μs Waiting time after FID measurement until next pulse application: 300 s Magic angle rotation speed: 11 kHz Number of integrations: 64 Measurement range: 250 ppm to -150 ppm Solid ３１ In measuring P-NMR spectra, chemical shifts were measured using (NH ４ ) ２ HPO ４ (chemical shift 1.0 ppm) is used.

[0107] solid ３１ Solid obtained by P-NMR measurement ３１ The P-NMR spectra are shown in FIG. 5 (compounds of Preparation Example 1 and Example 1), FIG. 6 (compounds of Examples 2 to 4), and FIG. 7 (compound of Example 5).

[0108] (4) Solubility <Static test> The compound (Li ３ P.S. ３ O-I ２ (1:1)) was added to anisole to prepare an anisole solution containing 20% ​​by mass of the compound. After leaving the anisole solution at room temperature (20°C) for 1 hour, the presence or absence of a precipitate was visually observed. As a result, no precipitate was observed. In addition, the compound (Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２A similar static test was also carried out on a 30 mass % anisole solution of Li (1:1)), but no precipitate was observed. Furthermore, for each of the compounds obtained in Example 3, Examples 6 to 7, and Comparative Example 3, the compound was added to anisole to prepare an anisole solution containing 30 mass % of the compound. This anisole solution was heated at 60°C for 30 minutes, allowed to cool (standing time: 1 hour), and then the state of the anisole solution was evaluated. As a result, slight turbidity occurred and insoluble matter was present in Example 6 and Comparative Example 3, but Examples 3 and 7 were uniformly dissolved without turbidity. Furthermore, a highly fluid solution was obtained in Example 7, and it is possible to further increase the solution concentration. <Centrifugal Separation Test> The compound (Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２ (1:1)) was added to anisole to prepare an anisole solution containing 30% by mass of the compound. This anisole solution was centrifuged at 4000 rpm for 15 minutes, and then visually observed for the presence or absence of precipitate. As a result, no precipitate was observed. These test results show that compound α has excellent solubility.

[0109] (5) Ionic Conductivity Each of the compounds obtained in Production Examples 1 and 2, Examples 1 to 3, and 7, and Comparative Examples 1 to 3 was placed in a cylindrical container and sandwiched between cylindrical SUS shafts inserted from both ends of the container. The resulting mixture was press-molded at room temperature (23°C) under a pressure of 333 MPa to form a disk-shaped powder compact. While maintaining the pressed state, lead wires were connected to the powder compact to measure its ionic conductivity. A Solartron 1470E Cell Test System manufactured by Solartron Analytical was used for the measurement. The ionic conductivity was calculated from the thickness of the press-molded powder compact. The results are shown in Table 1.

[0110]

[0111] From Table 1, it can be seen that the compounds of Examples 1 to 3 and 7 have high ionic conductivity, which is not significantly inferior to the compounds of Comparative Examples 1 to 3 (or the compounds of Production Examples 1 and 2).

[0112] 2. Sheet Production (Example 8) A slurry-like coating solution having the following composition was prepared. [Coating Solution Composition] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 95% by mass (0.76 g) The compound obtained in Example 3 (Li ３ P.S. ３ O-I ２ (1:1)): 5% by mass (0.04 g) Anisole: 76 parts by mass (0.61 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0113] Specifically, 0.04 g of the compound obtained in Example 3 was dissolved in 0.50 mL of anisole. ３ P.S. ４ 0.76 g of solid electrolyte was added, and the mixture was kneaded under the following kneading conditions using a planetary stirring degassing device ("MAZERUSTAR KK-250S" manufactured by Kurabo Industries, Ltd.). [Kneading conditions] Rotation: 1600 rpm Revolution: 1600 rpm Treatment time: 180 seconds x 3 Next, the sample was treated in an ultrasonic cleaner for 5 minutes, and then kneaded again under the same kneading conditions as above. Next, an additional 0.11 mL of anisole was added to the sample, and the mixture was further kneaded under the same kneading conditions as above, to obtain a slurry-like coating liquid (slurry solids concentration: 57% by mass).

[0114] The resulting coating solution was applied to a 5 cm x 10 cm 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), producing a solid electrolyte sheet (battery sheet). (The same applies to Examples 9 to 12 and Comparative Examples 4 and 5 described below.) The thickness of this solid electrolyte sheet (dried coating film not including the aluminum foil) was 100 to 120 μm.

[0115] Example 9 A solid electrolyte sheet was produced in the same manner as in Example 8, except that the composition of the coating solution was changed as follows: [Composition of Coating Solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 92% by mass (0.736 g) The compound obtained in Example 3 (Li３ P.S. ３ O-I ２ (1:1)): 8% by mass (0.064 g) Anisole: 73 parts by mass (0.59 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0116] (Example 10) A solid electrolyte sheet was produced in the same manner as in Example 8, except that the composition of the coating solution was changed as follows. [Composition of coating solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 95% by mass (0.76 g) The compound obtained in Example 7 (Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２ (1:1)): 5% by mass (0.04 g) Anisole: 62 parts by mass (0.50 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0117] Example 11 A solid electrolyte sheet was produced in the same manner as in Example 8, except that the composition of the coating solution was changed as follows: [Composition of coating solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 90% by mass (0.72 g) The compound obtained in Example 7 (Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２ (1:1)): 10 mass% (0.08 g) Anisole: 71 mass parts (0.57 mL) per 100 mass parts of the total amount of the above two components (total solid content)

[0118] (Example 12) A solid electrolyte sheet was produced in the same manner as in Example 8, except that the composition of the coating solution was changed as follows: [Composition of coating solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 95% by mass (0.76 g) The compound obtained in Example 6 (Li ３ P.S.７／２ O １／２ -I ２ (1:1)): 5% by mass (0.04 g) Anisole: 62 parts by mass (0.50 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0119] Comparative Example 4 A solid electrolyte sheet was produced in the same manner as in Example 6, except that the composition of the coating solution was changed as follows: [Composition of Coating Solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ): 95% by mass (0.76 g) The compound obtained in Comparative Example 3 (Li ３ P.S. ４ -I ２ (1:1)): 5% by mass (0.04 g) Anisole: 87 parts by mass (0.70 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0120] Comparative Example 5 A solid electrolyte sheet was produced in the same manner as in Example 6, except that the composition of the coating solution was changed as follows: [Composition of Coating Solution] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ Styrene-butadiene thermoplastic elastomer (SBS) ("TR2000" manufactured by JSR Corporation): 5% by mass (0.04 g) Anisole: 82 parts by mass (0.66 mL) per 100 parts by mass of the total amount of the above two components (total solid content)

[0121] Evaluation (1) Sheet Winding Characteristics Each of the solid electrolyte sheets obtained in Examples 8 to 12 and Comparative Examples 4 and 5 was wound around a cylinder with a diameter of 16 mm, and the presence or absence of breakage or peeling from the aluminum foil was visually observed. As a result, no breakage or peeling from the aluminum foil was observed in the solid electrolyte sheets obtained in Examples 8 to 12. Similarly, no breakage or peeling from the aluminum foil was observed in the solid electrolyte sheets obtained in Comparative Examples 4 and 5.

[0122] (2) Ionic Conductivity Each of the solid electrolyte sheets obtained in Examples 8 to 12 and Comparative Examples 4 and 5 was punched into a disk shape together with the aluminum foil, placed in a cylindrical container, and pressed at room temperature (23°C) under a pressure of 333 MPa by sandwiching the sheet between cylindrical SUS shafts inserted from both ends of the container. While maintaining the pressed state, lead wires were connected to the solid electrolyte sheet to measure the ionic conductivity. For the measurement, a "Cell test system 1470E" manufactured by Solartron Analytical was used. The ionic conductivity calculated based on the thickness of the pressed solid electrolyte sheet is shown in Table 2.

[0123]

[0124] 3. Battery Fabrication (Example 13) LiCoO ２ , Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ), acetylene black (AB) (manufactured by Denka Co., Ltd.), ２ :Li ３ P.S. ４ The compound (Li) obtained in Example 3 was mixed with the compound (Li) in a mass ratio of 70:30:5. ３ P.S. ３ O-I ２ A solution of 10 mg of LiCoO (1:1) in 0.1 mL of anisole was prepared, and the above mixture was added to this solution. The composition after addition was ２ :Li ３ P.S. ４ :AB:Li ３ P.S. ３ O-I ２ The ratio of the anisole content to the total weight of the composition was 70:30:5:5 (1:1). This composition was kneaded and treated in an ultrasonic cleaner for 5 minutes, and then approximately 0.05 mL of anisole was added and kneaded again to obtain a slurry (solid content concentration: 59% by mass). The obtained slurry was applied to a 5 x 10 cm Al foil to form a coating film. ｏ After drying at C for 10 hours, ｏ The sheet was then vacuum dried at C for 3 hours. The resulting sheet was punched out with a punch to obtain a positive electrode sheet having a diameter of 9.9 mm.

[0125] Li ３ P.S. ４ Solid electrolyte (Li obtained in Production Example 2) ３ P.S. ４ ) (80 mg) was placed in a cylindrical container with SUS shafts on both sides and pressed to form a solid electrolyte layer. Next, the positive electrode sheet obtained above was placed in the cylindrical container so as to overlap the solid electrolyte layer, and an In foil and a Li foil were placed in this order on the side of the solid electrolyte layer in the cylindrical container opposite the electrode sheet, followed by press-stacking and restraining with a dedicated jig to prepare a test cell (positive electrode half cell).

[0126] (Example 14) Instead of the compound obtained in Example 3, the compound obtained in Example 7 (Li ３ P.S. ４ -Li ３ P.S. ３ O(50 / 50)-I ２ A cell was fabricated in the same manner as in Example 13 except that a 1:1 mixture of ethylenediaminetetraacetic acid (E2) and ethylenediaminetetraacetic acid (E2) was used.

[0127] (Comparative Example 6) Instead of the compound obtained in Example 3, the compound obtained in Comparative Example 3 (Li ３ P.S. ４ -I ２ A cell was fabricated in the same manner as in Example 13 except that a 1:1 mixture of ethylenediaminetetraacetic acid (E2) and ethylenediaminetetraacetic acid (E2) was used.

[0128] Comparative Example 7 A cell was produced in the same manner as in Example 13, except that a styrene-butadiene thermoplastic elastomer (SBS) ("TR2000" manufactured by JSR Corporation) was used instead of the compound obtained in Example 3.

[0129] Evaluation (1) Initial Charge-Discharge Characteristics (Initial Charge-Discharge Curves) The initial charge-discharge curves (0.1 C) measured for each of the cells obtained in Examples 13 and 14 and Comparative Examples 6 and 7 are shown in Figure 8 (cells of Example 13 and Comparative Examples 6 and 7) and Figure 9 (cell of Example 14). Here, the 1 C rate (the amount of current required to discharge the full capacity of the battery in 1 hour) was 0.25 mA for the cell of Example 13, 0.29 mA for the cell of Example 14, 0.39 mA for the cell of Comparative Example 6, and 0.32 mA for the cell of Comparative Example 7. From Figures 8 and 9, it can be seen that the cells of Examples 13 and 14 were capable of being charged and discharged without any significant side reactions.

[0130] (2) AC Impedance (After Initial Charge) For each of the cells obtained in Examples 13 and 14 and Comparative Examples 6 and 7, AC impedance measurements were performed using a Solartron 1470E Cell test system manufactured by Solartron Analytical, and a Cole-Cole plot was obtained. The results (Cole-Cole plot) are shown in FIG. 10 (cells of Example 13 and Comparative Examples 6 and 7) and FIG. 11 (cell of Example 14). From FIGS. 10 and 11, it can be seen that the interfacial resistance after charging was small for the cells of Examples 13 and 14.

[0131] (3) Cycle Characteristics The results of the cycle characteristics measured for each of the cells obtained in Examples 13 and 14 and Comparative Examples 6 and 7 are shown in Fig. 12 (cells of Example 13 and Comparative Examples 6 and 7) and Fig. 13 (cell of Example 14). Fig. 12 and Fig. 13 show that the cells of Examples 13 and 14 have good cycle characteristics.

[0132] In the following tests, solid electrolytes containing S as a constituent element and further having a P-N bond were synthesized by the methods of the following Production Examples 4 and 5 in accordance with the description in the literature "Solid State Ionics 304 (2017) 85-89." Next, as shown in the following Examples 15 and 16, the solid electrolyte was reacted with iodine to synthesize compounds containing P and S as constituent elements, and having a group containing N bonded to the P and a disulfide bond.

[0133] (Production Example 4) Li ２S (Furuuchi Chemical Co., Ltd., 3N powder 200 Mesh), P ２ S ５ (Merck) and Li ３ N (manufactured by Hiroshima Wako Co., Ltd.) ２ S:P ２ S ５ :Li ３ The mixture was mixed in a molar ratio of N=60:25:10 and reacted by mechanical milling under the following conditions to obtain 60Li ２ S-25P ２ S ５ -10Li ３ N (glass powder, referred to as "LPS-10N") was obtained. [Mechanical milling conditions] Planetary ball mill: P7 manufactured by Fritsch GmbH Sample mass: 1.5 g Type: dry milling Ball: material: ZrO ２ , diameter 10 mm, number of pieces 10 Pot: material ZrO ２ , volume 45 mL Rotation: 510 rpm Processing time: 45 hours

[0134] (Production Example 5) Li ２ S (Idemitsu Kosan Co., Ltd., 3N powder 200 Mesh), P ２ S ５ (Merck) and Li ３ N (manufactured by Hiroshima Wako Co., Ltd.) ２ S:P ２ S ５ :Li ３ The mixture was mixed in a molar ratio of N=45:25:20 and reacted by mechanical milling in the same manner as in Production Example 4 to obtain 45Li ２ S-25P ２ S ５ -20Li ３ N (glass powder, referred to as "LPS-20N") was obtained.

[0135] (Example 15) To the LPS-10N obtained in Production Example 4, I ２ (5N irregular grains manufactured by Kojundo Chemical Co., Ltd.; crushed in a mortar) was used as LPS-10N:I. ２ A compound (referred to as DSP-10N) was obtained in the same manner as in Example 1, except that the molar ratio of DSP to DSP was 1:1.

[0136] (Example 16) The LPS-20N obtained in Production Example 5 was mixed with I ２ (5N irregular grains manufactured by Kojundo Chemical Co., Ltd.; crushed in a mortar) was used in LPS-20N:I ２ A compound (referred to as DSP-20N) was obtained in the same manner as in Example 1, except that the molar ratio of DSP to DSP was 1:1.

[0137] Evaluation (1) Raman Spectroscopic Analysis The compounds obtained in Examples 15 and 16 (DSP-10N and DSP-20N) were subjected to microscopic Raman spectroscopic analysis in the same manner as for the compound obtained in Production Example 1. The Raman spectra obtained by microscopic Raman spectroscopic analysis are shown in Figure 14. As shown in Figure 14, for both of the compounds obtained in Examples 15 and 16 (DSP-10N and DSP-20N), a Raman shift of 475 cm originating from the disulfide (S-S) bond of the P-S-S chain was observed. －１ A nearby peak (peak A mentioned above) was confirmed.

[0138] (2) X-ray photoelectron spectroscopy (XPS) The compounds obtained in Examples 15 and 16 (DSP-10N and DSP-20N) were measured by XPS using the following apparatus and conditions. Apparatus: VersaProbe II (ULVAC-PHI) Conditions: Excitation X-ray: monochromatic AlKα 1486.6 eV X-ray diameter and power: diameter 200 μm, 50 W, 15 kV (fixed at each point) Photoelectron detection angle: 45° Horizontal axis (binding energy): Charge neutralization correction was performed for all elements, with C-C at 284.8 eV. Measurements were performed on the outermost surface of the sample and on the GCIB (gas cluster ion beam) sputtered surface. GCIB treatment conditions were 10 kV, 30 nA, 2 × 2 mm ２ , 5 min. Data processing: 5-point smoothing

[0139] Figure 15 shows the measurement results for Example 15, and Figure 16 shows the measurement results for Example 16. As a result of the XPS measurement, it was confirmed that both of the compounds (DSP-10N and DSP-20N) obtained in Examples 15 and 16 contained N as a constituent element. For example, according to the aforementioned literature "Solid State Ionics 304 (2017) 85-89," for the substance corresponding to LPS-10N (Production Example 4), the N peak derived from the P-N=P bond was 396.9 eV, and the P ２ The N peak derived from the -N-P bond was observed at 398.3 eV. Although a slight peak shift was observed due to polymerization in the compounds obtained in Examples 15 and 16 (DSP-10N and DSP-20N), peaks were observed at positions close to 396.8 eV and 398.3 eV (see Figures 15 and 16). Furthermore, the elemental composition ratios were calculated as shown in Table 3, confirming that the N element was present in an amount of approximately 5 mol%.

[0140]

[0141] From the above results, it is presumed that the compounds obtained in Examples 15 and 16 have structures represented by the following formulas (13) and (14).

[0142]

[0143] Although several embodiments and / or examples of the present invention have been described in detail above, those skilled in the art will readily be able to make numerous modifications to these exemplary embodiments and / or examples without substantially departing from the novel teachings and advantages of the present invention. Accordingly, these numerous modifications are within the scope of the present invention. The contents of all documents cited in this specification and of the applications from which this application claims priority under the Paris Convention are incorporated by reference in their entirety.

Claims

1. Containing P and S as constituent elements, and a group bonded to the P and containing one or more elements selected from the group consisting of O, N, and halogen; A compound having a disulfide bond.

2. The compound of claim 1 , wherein the group comprises O.

3. The compound according to claim 1 or 2, which has a peak derived from a disulfide bond connecting two P's in Raman spectroscopy.

4. ３１ In the P-NMR measurement, ｘ O ｙ The compound according to claim 1 or 2, having a peak derived from the structure (wherein 1≦x and 0<y).

5. Said P.S. ｘ O ｙ The peaks due to the structure are ３ The compound according to claim 4 , wherein the peak is derived from an O structure.

6. The compound according to claim 1 or 2, comprising a structure represented by the following formula (1): 【Chemistry 11】 (In formula (1), X is any group.)

7. The compound according to claim 1 or 2, comprising a structure represented by the following formula (1) and a structure represented by the following formula (7): 【Chemistry 12】 (In formulas (1) and (7), X is any group, and multiple Xs may be the same or different.)

8. 3. The compound according to claim 1, comprising, as a constituent element, one or more elements selected from the group consisting of Li, Na, Mg, and Al.

9. 3. The compound according to claim 1 or 2, which is obtained by adding an oxidizing agent to a raw material compound containing, as constituent elements, P and S, and one or more elements selected from the group consisting of O, N and halogen, and then reacting the raw material compound with the oxidizing agent.

10. The compound according to claim 1 or 2, comprising a disulfide bond formed by the following reaction formula (9): 【Chemistry 13】 (In the formula, R is a group containing one or more elements selected from the group consisting of O, N, and halogen. X is a halogen.)

11. The compound according to claim 10, wherein X in the reaction formula (9) is iodine (I), fluorine (F), chlorine (Cl) or bromine (Br).

12. A binder for a battery comprising the compound according to claim 1 or 2.

13. 13. The battery binder of claim 12, comprising a halogen.

14. 14. The battery binder of claim 13, wherein the halogen is I or Br.

15. 13. A battery electrode mix layer or electrolyte layer comprising the battery binder according to claim 12.

16. 16. The battery electrode mix layer or electrolyte layer according to claim 15, further comprising a solid electrolyte.

17. A sheet for a battery comprising at least one selected from the group consisting of the electrode mixture layer for a battery according to claim 15 and an electrolyte layer.

18. A battery comprising a compound according to claim 1 or 2.

19. Adding an oxidizing agent to a raw material compound containing P and S as constituent elements, and one or more elements selected from the group consisting of O, N and halogens; and reacting said raw material compound with said oxidizing agent; A method for producing a compound, comprising:

20. The method for producing a compound according to claim 19, wherein the raw material compound contains one or more constituent elements selected from the group consisting of Li, Na, Mg, and Al.

21. The raw material compound is PS ｘ O ｙ 21. A method for preparing a compound according to claim 19 or 20, comprising the structure: wherein 1≦x and 0<y.

22. Said P.S. ｘ O ｙ The structure is PS ３ A method for producing the compound according to claim 21, which is an O-structure.

23. The method for producing a compound according to claim 19 or 20, wherein the oxidizing agent is a halogen alone.

24. The halogen element is I ２ Or Br ２ 24. A method for producing the compound according to claim 23,

25. The method for producing a compound according to claim 19 or 20, wherein the raw material compound and the oxidizing agent are reacted with one or more energy sources selected from the group consisting of physical energy, thermal energy, and chemical energy.

26. The method for producing a compound according to claim 19 or 20, wherein the raw material compound and the oxidizing agent are reacted in a liquid.

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