Electrode mixture and battery

Abstract

The main purpose of this disclosure is to provide an electrode mixture capable of suppressing an increase in battery resistance.　For this purpose, the disclosure provides an electrode mixture containing an electrode active material, a sulfide solid electrolyte containing a lithium element, a sulfur element, and a phosphorus element, and an organic compound, wherein the organic compound has two or more benzene rings, and at least a portion of the organic compound is present between the electrode active material and the sulfide solid electrolyte.

Description

Electrode mixture and battery

[0001] The present disclosure relates to an electrode mixture and a battery.

[0002] In recent years, the development of batteries has been actively carried out. For example, in the automotive industry, various studies and developments are being carried out on batteries to be used in electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), or hybrid electric vehicles (HEVs).

[0003] For example, Patent Document 1 discloses a modified sulfide solid electrolyte for use in a battery. The modified sulfide solid electrolyte has a BET specific surface area of ​​10 m ２ / g or more, containing a sulfide solid electrolyte and an epoxy compound, and in an infrared absorption spectrum by FT-IR analysis (ATR method), －１ It has a peak at

[0004] International Publication No. 2022 / 158458

[0005] Sulfide solid electrolytes have attracted attention as battery materials, particularly as electrode layer materials, due to their excellent ionic conductivity. However, batteries using sulfide solid electrolytes are susceptible to deterioration (oxidation or reduction) of the sulfide solid electrolyte through repeated charge and discharge cycles, resulting in increased resistance.

[0006] The present disclosure has been made in view of the above circumstances, and has as its main object to provide an electrode mixture that can suppress an increase in battery resistance.

[0007] [1] An electrode mixture containing an electrode active material, a sulfide solid electrolyte containing lithium, sulfur, and phosphorus, and an organic compound, wherein the organic compound has two or more benzene rings, and at least a portion of the organic compound is present between the electrode active material and the sulfide solid electrolyte.

[0008] [2] The electrode mixture according to [1], containing at least one of a compound represented by the following general formula (1) or the following general formula (2) as the organic compound:

[0009] (In the formula, R １ and R２ are each independently an organic group, and R ３ ~R １０ are each independently a hydrogen atom or a substituent, and n is an integer of 0 to 4.

[0010] [3] The above R １ and the above R ２ At least one of the above is an organic group represented by the following general formula (3):

[0011] (In the formula, X represents an organic group, and * represents a bond.)

[0012] [4] The electrode mixture according to [3], wherein the X has an epoxy group.

[0013] [5] The electrode mixture according to any one of [1] to [4], wherein the organic compound contains 9,9-bis(4-glycidyloxyphenyl)fluorene represented by the following chemical formula (1):

[0014]

[0015] [6] The electrode mixture according to any one of [1] to [5], containing a compound represented by the following general formula (4) as the organic compound:

[0016] (wherein S is an organic group, n is 0 or 1, and R １１ ~R ２０ are each independently a hydrogen atom or a substituent.

[0017] [7] The electrode mixture according to [6], wherein the S has an epoxy group.

[0018] [8] The electrode mixture according to [6] or [7], wherein the S is an organic group represented by the following general formula (5):

[0019] (wherein T and U are each independently an organic group; n １ and n ２ are each independently 0 or 1, and * represents a bond.

[0020] [9] The electrode mixture according to any one of [1] to [8], wherein the organic compound contains 1,3-diphenyl-2,3-epoxy-1-propanone represented by the following chemical formula (2):

[0021]

[0022]

[10] The electrode mixture according to [1], wherein the organic compound has a sulfonyl group.

[0023]

[11] The electrode mixture according to

[10] , containing a compound represented by the following general formula (6) as the organic compound:

[0024] (In the formula, R ２１ ~R ３０ are each independently a hydrogen atom, a substituent, or an organic group.

[0025]

[12] The above R ２１ ~ Above R ３０ At least one of the above is an organic group represented by the following general formula (7) or the following general formula (8).

[0026] (wherein α and β each independently represent an organic group, n １ and n ２ are each independently 0 or 1, and * represents a bond.

[0027]

[13] The electrode mixture according to any one of [1] to

[12] , wherein the organic compound contains tetraglycidyl-3,3'-diaminodiphenylsulfone represented by the following chemical formula (3):

[0028]

[0029]

[14] The above R ２１ ~ Above R ３０ At least one of the above is an organic group represented by the following general formula (9):

[0030] (In the formula, γ represents an organic group, n represents 0 or 1, and * represents a bond.)

[0031]

[15] The electrode mixture according to any one of [1] to

[14] , containing a diglycidyl ether sulfone-based compound represented by the following chemical formula (4) as the organic compound:

[0032]

[0033]

[16] The organic compound has a structure represented by the following structural formula (1), a structure represented by the following structural formula (2), a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (1) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (2) is substituted with a group having a molecular weight of 50 or less. The electrode mixture according to [1].

[0034] (In the formula, * represents a bond, and n is an integer of 0 to 4.)

[0035]

[17] The organic compound has a structure represented by the following structural formula (3-1), a structure represented by the following structural formula (3-2), a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (3-1) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (3-2) is substituted with a group having a molecular weight of 50 or less. The electrode mixture according to [1].

[0036] (In the formula, * means a bond.)

[0037]

[18] The organic compound has a structure represented by the following structural formula (4-1), a structure represented by the following structural formula (4-2), a structure represented by the following structural formula (4-3), a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-1) is substituted with a group having a molecular weight of 50 or less, a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-2) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-3) is substituted with a group having a molecular weight of 50 or less. The electrode mixture according to [1].

[0038] (In the formula, * means a bond.)

[0039]

[19] The value of the Hansen solubility parameter of the organic compound is 8.0 MPa ０．５ The electrode mixture according to any one of [1] to

[18] above.

[0040]

[20] The electrode mixture according to any one of [1] to

[19] , wherein the ratio of the organic compound to the sulfide solid electrolyte is greater than 0.50 mass% and less than 14.0 mass%.

[0041]

[21] The electrode mixture according to any one of [1] to

[20] , wherein the electrode mixture is a negative electrode mixture.

[0042]

[22] The electrode mixture according to

[21] , wherein the electrode active material is a Si-based active material.

[0043]

[23] The electrode mixture according to any one of [1] to

[20] , wherein the electrode mixture is a positive electrode mixture.

[0044]

[24] The electrode mixture according to

[22] , wherein the electrode active material is an oxide active material containing at least Ni and Co elements.

[0045]

[25] A battery having a positive electrode active material layer, a negative electrode active material layer, and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein at least one of the positive electrode active material layer and the negative electrode active material layer contains the electrode mixture according to any one of [1] to

[24] .

[0046] The present disclosure provides an effect of suppressing an increase in the resistance of the battery.

[0047] FIG. 1 is a schematic cross-sectional view illustrating an electrode composite according to the present disclosure; FIG. 2 is a schematic cross-sectional view illustrating a battery according to the present disclosure; FIG. 3 is a graph showing typical results of a resistance increase rate; FIG. 4 is a graph showing typical results of a resistance increase rate; FIG. 5 is a graph showing typical results of an XPS measurement; FIG. 6 is a graph showing typical results of an XPS measurement; FIG. 7 is a graph showing results of a resistance increase rate for each example and each comparative example; FIG. 8 is a graph showing results of a resistance increase rate for each example and each comparative example.

[0048] The electrode mixture and the battery according to the present disclosure will be described in detail below. Note that the drawings shown below are schematic illustrations, and the size and shape of each part are appropriately exaggerated for ease of understanding.

[0049] A. Electrode Mixture The electrode mix of the present disclosure contains an electrode active material, a sulfide solid electrolyte containing lithium, sulfur, and phosphorus, and an organic compound. The organic compound has two or more benzene rings. As shown in FIG. 1 , in the electrode mix 10, at least a portion of the organic compound 3 is present between the electrode active material 1 and the sulfide solid electrolyte 2.

[0050] According to the present disclosure, the electrode mixture contains an organic compound, the organic compound has two or more benzene rings, and at least a portion of the organic compound is present between the electrode active material and the sulfide solid electrolyte, so that deterioration of the sulfide solid electrolyte (oxidation or reduction of the sulfide solid electrolyte) can be suppressed.

[0051] As described above, sulfide solid electrolytes may deteriorate during battery charging and discharging. For example, in the positive electrode active material layer, oxygen atoms released from the positive electrode active material may oxidize the sulfide solid electrolyte. On the other hand, since the electrode composite of the present disclosure has two or more benzene rings, at least a portion of which is present between the electrode active material (positive electrode active material) and the sulfide solid electrolyte, it is presumed that the organic compound functions as a barrier. Similarly, in the negative electrode active material layer, it is presumed that the organic compound functions as a barrier to suppress side reactions of the sulfide solid electrolyte (improve reduction resistance). Here, the benzene ring has a conjugated structure in which double bonds and single bonds are alternately connected, and has a π electron cloud. Therefore, in organic compounds with multiple benzene rings, the region in which the π electron cloud extends is wide, resulting in improved chemical stability (oxidation resistance, reduction resistance). As a result, it is presumed that the chemical stability of sulfide solid electrolytes located near such organic compounds is also improved. These mechanisms are presumed to suppress resistance increases in batteries using the electrode composite of the present disclosure.

[0052] Furthermore, if the electronic conductivity of the electrode layer is too high, it may accelerate the deterioration of the conductive additive. In contrast, the organic compound of the present disclosure can moderately suppress the electronic conductivity. As a result, it is presumed that the deterioration of the conductive additive can be suppressed and the increase in resistance can be suppressed.

[0053] 1. Organic Compound The organic compound in the present disclosure is a compound having two or more benzene rings. The number of benzene rings may be three or more, four or more, or five or more. On the other hand, the number of benzene rings is, for example, eight or less. Furthermore, the number of benzene rings in the organic compound may be any of 2, 3, 4, 5, 6, 7, and 8.

[0054] Examples of organic compounds having multiple benzene rings include condensed polycyclic hydrocarbons such as naphthalene, anthracene, fluorene, phenalene, tetracene, and pentacene, derivatives of condensed polycyclic hydrocarbons, biphenyl and its derivatives, and compounds in which multiple benzene rings are connected by organic groups.

[0055] In the organic compound of the present disclosure, it is preferable that the conjugation inside the benzene ring extends to the outside of the benzene ring. For example, in the compounds represented by the general formulas (1) and (2) described below, two benzene rings are connected by a single bond, so that the conjugation inside one benzene ring extends to the outside of that benzene ring (the other benzene ring). It is presumed that the wider range of conjugation improves the conductivity of carrier ions such as lithium ions.

[0056] Examples of the organic compound in the present disclosure include compounds (fluorene derivatives) represented by the following general formula (1) or (2).

[0057]

[0058] In the above general formulas (1) and (2), R １ and R ２are each independently an organic group. Here, in the present disclosure, an "organic group" is a group having at least hydrogen atoms and carbon atoms. The organic group may be a group composed only of hydrogen atoms and carbon atoms, or may be a group further containing other atoms. Examples of other atoms include at least one of an oxygen atom, a nitrogen atom, a phosphorus atom, a sulfur atom, and a halogen atom. Furthermore, the organic group may be a group composed only of hydrogen atoms, carbon atoms, and oxygen atoms, or may be a group composed only of hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms.

[0059] The number of carbon atoms in the organic group is not particularly limited, and may be, for example, 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, or 20 or less, 18 or less, or 16 or less. The number of carbon atoms in the organic group may be any range from 1 to 20. The organic group may be linear, branched, or cyclic. The organic group may partially have a ring structure such as a benzene ring. The organic group may or may not have a specific functional group. Examples of functional groups include hydroxy groups, ether groups, epoxy groups, carbonyl groups, amino groups, cyano groups, nitro groups, sulfo groups, sulfonyl groups, allyl groups, and halogen elements (halogeno groups) such as Cl and Br. The organic group preferably has an epoxy group at the terminal or interior of its molecular structure. The organic group may also be an alkyl group having 5 or less carbon atoms. The alkyl group may have 3 or less carbon atoms, or may have 1 or 2 carbon atoms. The organic group may have only one or two or more of the above-mentioned functional groups. The organic group may have only one or two or more of the above-mentioned functional groups.

[0060] The above R １ and the above R ２ Examples of R include organic groups represented by the following general formula (3): １ and R ２One of R may be an organic group represented by the following general formula (3), or both may be organic groups represented by the following general formula (3). １ and R ２ may be organic groups having the same structure. １ and R ２ may be organic groups represented by the following general formula (3) and having the same structure.

[0061]

[0062] In the general formula (3), X represents an organic group, and * represents a bond. That is, the organic group represented by the general formula (3) is bonded to another atom (e.g., carbon) constituting the organic compound at *. The meaning of the bond is the same in the following examples. The organic group is the same as that described for the general formulas (1) and (2). In particular, X preferably has an epoxy group. Furthermore, X preferably has an epoxy group at its terminal. Furthermore, X preferably has an epoxy group and an ether group (ether bond) between the epoxy group and the benzene ring represented by the general formula (3). The oxygen atom in the ether group (ether bond) may be directly bonded to a carbon atom in the benzene ring represented by the general formula (3). Furthermore, the oxygen atom in the ether group (ether bond) may be directly bonded to a carbon atom in the epoxy group or may be bonded via an alkyl group having 1 to 3 carbon atoms. Furthermore, in the general formula (3), the positional relationship between the bond and X may be ortho, meta, or para.

[0063] In addition, in the above general formulas (1) and (2), R ３ ~R １０ are each independently a hydrogen atom or a substituent (of a hydrogen atom). Examples of the substituent include the above-mentioned functional groups and alkyl groups having 1 to 10 carbon atoms. The number of carbon atoms in the alkyl group may be 1 or more and 5 or less, 1 or 2 or more. ３ ~R １０Among the six R's, the number of R's that are hydrogen atoms is not particularly limited, but may be four or more, five or more, or six.

[0064] In the general formula (2), n is an integer of 0 to 4. When n is 0, (CH ２ ) n is a single bond. That is, the carbon atom of the 5-membered ring in general formula (2) and CHR １ R ２ is directly bonded to "C (carbon atom)" in the formula.

[0065] A specific example of the organic compound represented by the above general formula (1) is 9,9-Bis(4-glycidyloxyphenyl)fluorene represented by the following chemical formula (1).

[0066]

[0067] Furthermore, examples of the organic compound in the present disclosure include compounds represented by the following general formula (4).

[0068]

[0069] In the general formula (4), S is an organic group. n is 0 or 1. R １１ ~R ２０ are each independently a hydrogen atom or a substituent (of a hydrogen atom). The organic group and the substituent (functional group) are the same as those described in the general formulas (1) and (2). It is preferable that the above S has an epoxy group. In addition, R １１ ~R ２０ Of the 10 R's, the number of R's that are hydrogen atoms is not particularly limited, but may be 6 or more, 8 or more, 9 or more, or even 10. In addition, in the above general formula (4), when n is 0, R １１ ~R １５ and carbon atoms in a benzene ring containing R １６ ~R ２０ is directly bonded to a carbon atom in a benzene ring containing

[0070] Here, examples of S include organic groups represented by the following general formula (5): As represented by general formula (5), the organic group in the present disclosure may contain an epoxy group and a carbonyl group.

[0071]

[0072] In the general formula (5), T and U each independently represent an organic group; １ and n ２ are each independently 0 or 1, and * represents a bond. The organic group is as described above. １ When n is 0, the carbon atom in the epoxy group is directly bonded to another atom constituting the organic compound (for example, a carbon atom in a benzene ring). ２ When is 0, the carbon atom in the epoxy group and the carbon atom in the carbonyl group are directly bonded. T and U may be composed only of carbon atoms and hydrogen atoms. The number of carbon atoms in T is, for example, 5 or less, may be 3 or less, or may be 1 or 2. The number of carbon atoms in U is, for example, 5 or less, may be 3 or less, or may be 1 or 2.

[0073] A specific example of the organic compound represented by the above general formula (4) is 1,3-diphenyl-2,3-epoxy-1-propanone represented by the following chemical formula (2).

[0074]

[0075] As described above, the organic compound in the present disclosure has two or more benzene rings. Preferably, the organic compound further has a sulfonyl group. The sulfonyl group in the organic compound improves the conductivity of metal ions such as Li ions.

[0076] Examples of organic compounds having a sulfonyl group include compounds represented by the following general formula (6).

[0077]

[0078] In the above general formula (6), R ２１ ~R３０ are each independently a hydrogen atom, a substituent (of a hydrogen atom), or an organic group. The organic group and the substituent (functional group) are the same as those described in the general formulas (1) and (2). In particular, it is preferable that the organic group has an epoxy group at the end of the molecular structure. ２１ ~R ２５ Among the five R's, the number of R's that are hydrogen atoms is not particularly limited, but may be 3 or more, 4 or more, or even 5. ２６ ~R ３０ Among the five Rs, the number of Rs that are hydrogen atoms is not particularly limited, but may be 3 or more, 4 or more, or even 5. ２１ ~R ２５ Among the five Rs, the number of Rs that are organic groups is not particularly limited, but may be two or less, or may be one. ２６ ~R ３０ Among the five Rs, the number of Rs that are organic groups is not particularly limited, but may be two or less, or may be one. ２１ ~R ２５ Of the five R's, the number of R's that are hydrogen atoms may be four, and the number of R's that are organic groups may be one. ２６ ~R ３０ Of the five R's, the number of R's that are hydrogen atoms may be four, and the number of R's that are organic groups may be one. ２１ ~R ２５ and a benzene ring structure having R ２６ ~R ３０ The structure of the benzene ring having the formula (6) is preferably symmetrical with respect to the sulfonyl group. For example, the compounds represented by the chemical formulas (3) and (4) described below have symmetrical structures with respect to the sulfonyl group. Furthermore, in one benzene ring in the general formula (6), the positional relationship between the sulfonyl group and the organic group may be ortho, meta, or para.

[0079] R ２１ ~R ３０ At least one of the above may be an organic group represented by the following general formula (7) or (8).

[0080]

[0081] In the above general formulas (7) and (8), α and β each independently represent an organic group. １ and n ２ are each independently 0 or 1. １ or n ２ When is 0, the nitrogen atom in general formulas (7) and (8) and the carbon atom in the epoxy group are directly bonded. * denotes a bond. The organic group is the same as that described in general formulas (1) and (2). α and β may be composed only of carbon atoms and hydrogen atoms. The number of carbon atoms in α is, for example, 3 or less, may be 2 or less, or may be 1. The number of carbon atoms in β is, for example, 3 or less, may be 2 or less, or may be 1.

[0082] A specific example of the organic compounds represented by general formula (6) and general formula (8) is tetraglycidyl-3,3'-diaminodiphenylsulfone represented by the following chemical formula (3).

[0083]

[0084] Also, R ２１ ~R ３０ At least one of the groups may be an organic group represented by the following general formula (9).

[0085]

[0086] In the above general formula (9), γ is an organic group. Furthermore, n is 0 or 1. When n is 0, the oxygen atom in general formula (9) (the oxygen atom that does not constitute the epoxy group) is directly bonded to the carbon atom in the epoxy group. Furthermore, * means a bond. The organic group is the same as that described in general formulas (1) and (2). γ may be composed only of carbon atoms and hydrogen atoms. The number of carbon atoms in γ is, for example, 3 or less, may be 2 or less, or may be 1.

[0087] Specific examples of the organic compounds represented by general formula (6) and general formula (9) include diglycidyl ether sulfone compounds represented by the following chemical formula (4).

[0088]

[0089] The organic compound in the present disclosure may have a polymerizable functional group such as an epoxy group. The organic compound may be polymerized via the polymerizable functional group such as an epoxy group. That is, the organic compound may be an oligomer having two or more and five or less identical structural units, or may be a polymer having more than five identical structural units.

[0090] The organic compound may have a structure represented by the following structural formula (1), a structure represented by the following structural formula (2), a structure in which at least one hydrogen atom bonded to the benzene ring of the following structural formula (1) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen atom bonded to the benzene ring of the following structural formula (2) is substituted with a group having a molecular weight of 50 or less.

[0091] (In the formula, * represents a bond, and n is an integer of 0 to 4.)

[0092] The * in structural formula (1) or structural formula (2) indicates a bond to another atom. An organic compound may have one or more structures represented by structural formula (1) or structural formula (2). The positional relationship between carbon (C) and oxygen (O) bonded to one benzene ring in a structure represented by structural formula (1) or structural formula (2) may be ortho, meta, or para. An organic compound may have a structure in which at least one hydrogen atom bonded to the benzene ring of structural formula (1) or structural formula (2) is substituted with a group having a molecular weight of 50 or less (especially, a group having a molecular weight of 30 or less). The group having a molecular weight of 50 or less is not particularly limited, but examples include a methyl group, an ethyl group, a propyl group, a hydroxyl group, and an amino group. The number of hydrogen atoms substituted with groups having a molecular weight of 50 or less (especially, a group having a molecular weight of 30 or less) among the hydrogen atoms bonded to the benzene ring of structural formula (1) or structural formula (2) may be one, two, three, four, or five or more.

[0093] The organic compound may have a structure represented by the following structural formula (3-1), a structure represented by the following structural formula (3-2), a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (3-1) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (3-2) is substituted with a group having a molecular weight of 50 or less.

[0094] (In the formula, * means a bond.)

[0095] The * in structural formula (3-1) or structural formula (3-2) indicates a bond to another atom. The organic compound may have one or more structures represented by structural formula (3-1) or structural formula (3-2). The organic compound may have a structure in which at least one of the hydrogen atoms bonded to the benzene ring of structural formula (3-1) or structural formula (3-2) is substituted with a group having a molecular weight of 50 or less (especially, a group having a molecular weight of 30 or less). The group having a molecular weight of 50 or less is the same as described above. The number of hydrogen atoms substituted with groups having a molecular weight of 50 or less (especially, a group having a molecular weight of 30 or less) among the hydrogen atoms bonded to the benzene ring of structural formula (3-1) or structural formula (3-2) may be 1, 2, 3, 4, or 5 or more.

[0096] The organic compound may have a structure represented by structural formula (4-1), a structure represented by structural formula (4-2), a structure represented by structural formula (4-3), a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of structural formula (4-1) is substituted with a group having a molecular weight of 50 or less, a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of structural formula (4-2) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen atom among the hydrogen atoms bonded to the benzene ring of the following structural formula (4-3) is substituted with a group having a molecular weight of 50 or less.

[0097] (In the formula, * means a bond.)

[0098] The * in structural formula (4-1), structural formula (4-2), or structural formula (4-3) indicates a bond to another atom. The organic compound may have one or more structures represented by structural formula (4-1), structural formula (4-2), or structural formula (4-3). The positional relationship between sulfur (S) and nitrogen (N), oxygen (O), or carbon (C) bonded to one benzene ring in the structure represented by structural formula (4-1), structural formula (4-2), or structural formula (4-3) may be ortho, meta, or para. Furthermore, at least one hydrogen atom bonded to the benzene ring of structural formula (4-1), structural formula (4-2), or structural formula (4-3) may be substituted with a group having a molecular weight of 50 or less (especially a group having a molecular weight of 30 or less). The same applies to groups having a molecular weight of 50 or less. Of the hydrogen atoms bonded to the benzene ring of Structural Formula (4-1), Structural Formula (4-2), or Structural Formula (4-3), the number of hydrogen atoms substituted with groups having a molecular weight of 50 or less (particularly, groups having a molecular weight of 30 or less) may be 1, 2, 3, 4, or 5 or more.

[0099] The organic compound in the present disclosure preferably has a high Hansen Solubility Parameter (HSP) value. This is because it can prevent deterioration (oxidation) of the electrode active material, particularly due to oxygen. The HSP value of the organic compound is, for example, 8.0 MPa. ０．５ or more, 8.5 MPa ０．５ It may be 9.0 MPa or more. ０．５ It may be 9.5 MPa or more. ０．５ Among the compounds represented by the above chemical formulas (1) to (4), the HSP value of the compound represented by chemical formula (1) is 10.13 MPa or more. ０．５ The HSP value of the compound represented by chemical formula (2) is 11.04 MPa. ０．５ The HSP value of the compound represented by chemical formula (3) is 11.62 MPa. ０．５ The HSP value of the compound represented by chemical formula (4) is 9.94 MPa. ０．５ In addition, among the compounds represented by chemical formulas (5) and (6) used in the comparative examples described later, the HSP value of the compound represented by chemical formula (5) is 8.26 MPa.０．５ The HSP value of the compound represented by chemical formula (6) is 7.33 MPa. ０．５ The type of organic compound contained in the electrode mixture may be one type or two or more types. The structure of the organic compound in the electrode mixture can be identified by, for example, gas chromatography mass spectrometry (GC-MS) or time-of-flight secondary ion mass spectrometry (TOF-SIMS).

[0100] Furthermore, at least a portion of the organic compound in the electrode mixture according to the present disclosure is present between the electrode active material and the sulfide solid electrolyte. This allows the organic compound in the present disclosure to function as a barrier and protect the sulfide solid electrolyte. The term "between the electrode active material and the sulfide solid electrolyte" in the electrode mixture envisions at least the following three positions: (1) a position in direct contact with both the electrode active material and the sulfide solid electrolyte, (2) a position in direct contact with one of the electrode active material and the sulfide solid electrolyte and indirect contact with the other, and (3) a position indirectly contacting both the electrode active material and the sulfide solid electrolyte. "Indirect contact" refers to contact via a conductive additive or the like, as described below. Note that, if the electrode active material has an ion-conductive coating layer, as described below, an organic substance may be present between the coating layer and the sulfide solid electrolyte. Here, the organic compound in the present disclosure is preferably present at least in the position (2). In particular, as described below, the organic compound preferably coats the sulfide solid electrolyte. Since the distance between the sulfide solid electrolyte and the organic compound is shorter, a better barrier function is exhibited. Note that since the proportions of the conductive additive and binder are expected to be smaller than those of the electrode active material and the sulfide solid electrolyte, even if the organic compound is present at the position (3), the distance between the sulfide solid electrolyte and the organic compound is sufficiently short to exhibit the barrier function.

[0101] The organic compound may coat the electrode active material. The organic compound may be present on the surface of the electrode active material. When the electrode active material has a coating layer described below, the organic compound may be present on the surface of the coating layer opposite to the electrode active material. The organic compound may also coat the sulfide solid electrolyte. The coverage rate of the organic compound is, for example, 50% or more and 95% or less. The proportion of the organic compound present between the electrode active material and the sulfide solid electrolyte relative to the total volume of the organic compound is, for example, 10% by volume or more and 50% by volume or less. The location and the proportion of the organic compound can be determined by microscopic observation using a scanning electron microscope (SEM) or the like.

[0102] The proportion of the organic compound in the electrode mixture is not particularly limited, but is, for example, 0.05% by mass or more and 3.0% by mass or less. The proportion of the organic compound relative to the sulfide solid electrolyte described below is also not particularly limited, but may be, for example, greater than 0.50% by mass, 1.0% by mass or more, 3.0% by mass or more, or 5.0% by mass or more. On the other hand, the proportion of the organic compound relative to the sulfide solid electrolyte may be, for example, less than 14.0% by mass, 13.0% by mass or less, 10.0% by mass or less, or 8.0% by mass or less.

[0103] 2. Sulfide Solid Electrolyte The sulfide solid electrolyte in the present disclosure contains lithium, sulfur, and phosphorus. The sulfide solid electrolyte preferably contains sulfur (S) as a main anion element.

[0104] The sulfide solid electrolyte may further contain an X element (X is at least one of As, Sb, Si, Ge, Sn, B, Al, Ga, and In). The sulfide solid electrolyte may further contain at least one of an O element and a halogen element.

[0105] The sulfide solid electrolyte is an ortho-composition of PS ４ ３－ It is preferable that the anion structure has a PS structure as the main component, because this has high chemical stability. ４ ３－The proportion of the structure is, for example, 70 mol % or more, and may be 90 mol % or more, based on the total anionic structures in the sulfide solid electrolyte.

[0106] Examples of sulfide solid electrolytes include Li ２ S-P ２ S ５ , Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -GeS ２ , Li ２ S-P ２ S ５ -Li ２ O, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li ２ S-P ２ S ５ -LiI-LiBr, Li ２ S-SiS ２ -P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Z ｍ S ｎ (where m and n are positive numbers. Z is Ge, Zn, or Ga.), Li ２ S-SiS ２ -Li ３ P.O. ４ Examples include:

[0107] The sulfide solid electrolyte may be glass (amorphous), crystallized glass (glass ceramics), or a crystalline sulfide solid electrolyte. Examples of the crystalline phase of the crystalline sulfide solid electrolyte include a Thio-LISICON-type crystalline phase, an LGPS-type crystalline phase, and an Argyrodite-type crystalline phase.

[0108] The ionic conductivity of the sulfide solid electrolyte is not particularly limited, but a higher value is preferable. The ionic conductivity at 25° C. is, for example, 0.1 mS / cm or more and 10 mS / cm or less.

[0109] The sulfide solid electrolyte may be in the form of particles, for example. ５０ ) is, for example, 0.1 μm or more and 50 μm or less. ５０ ) refers to the cumulative 50% particle size in the volume-based particle size distribution measured by a laser diffraction particle size distribution analyzer. The proportion of the sulfide solid electrolyte in the electrode mixture is not particularly limited, but is, for example, 8 mass% or more and 30 mass% or less.

[0110] 3. Electrode Active Material The electrode active material may be a negative electrode active material or a positive electrode active material.

[0111] Examples of negative electrode active materials include Si-based active materials, carbon-based active materials, and Li-based active materials. Among these, Si-based active materials are preferred. The Si-based active material is an active material containing elemental Si. Examples of Si-based active materials include simple Si, Si alloys, and Si oxides. The Si-based active material may also be a Si-C composite active material in which Si is present on the surface of a carbon (C) support. The Si alloy preferably contains elemental Si as a main component. The proportion of elemental Si in the Si alloy is, for example, 50 mol% or more, or may be 70 mol% or more, or may be 90 mol% or more. On the other hand, the proportion of elemental Si in the Si alloy is, for example, 99 mol% or less. Examples of Si alloys include Si-Al alloys, Si-Sn alloys, Si-In alloys, Si-Ag alloys, Si-Pb alloys, Si-Sb alloys, Si-Bi alloys, Si-Mg alloys, Si-Ca alloys, Si-Ge alloys, and Si-Pb alloys. The Si alloys may be binary alloys or multi-component alloys of ternary or higher components. Examples of Si oxides include SiO.

[0112] The Si-based active material may have a diamond-type crystalline phase, a clathrate I-type crystalline phase, or a clathrate II-type crystalline phase. In the clathrate I-type or II-type crystalline phase, a polyhedron (cage) including a pentagon or hexagon is formed by multiple Si elements. This polyhedron has a space inside that can encapsulate metal ions such as Li ions, thereby suppressing volume change due to charge and discharge.

[0113] The Si-based active material may have voids inside the primary particles. The voids can suppress volumetric changes in the active material and prevent cracking of the electrode layer (negative electrode active material layer). The void ratio is not particularly limited, but is, for example, 4% or more and 40% or less. The presence of voids in the primary particles and the void ratio can be confirmed by observation with a scanning electron microscope (SEM).

[0114] The carbon-based active material is an inorganic active material containing the element C, such as graphite, hard carbon, and soft carbon. The Li-based active material is an active material containing the element Li, such as simple Li and Li alloys.

[0115] The shape of the negative electrode active material may be, for example, particulate or layered. ５０ ) is, for example, 10 nm or more and 50 μm or less. ５０ ) is defined above.

[0116] The positive electrode active material may be, for example, an oxide active material. ２ , LiMnO ２ , LiNiO ２ , LiVO ２ , LiNi １／３ Co １／３ Mn １／３ O ２ Rock salt layered active materials such as LiMn ２ O ４ , Li ４ Ti ５ O １２ , Li(Ni ０．５ Mn １．５ ) O ４Spinel-type active materials such as LiFePO ４ , LiMnPO ４ , LiNiPO ４ , LiCoPO ４ Among these, LiNi １／３ Co １／３ Mn １／３ O ２ As described above, an oxide active material containing at least Ni and Co elements is preferred.

[0117] The shape of the positive electrode active material may be, for example, particulate or layered. ５０ ) is, for example, 10 nm or more and 50 μm or less. ５０ ) is as described above.

[0118] The electrode active material may have an ion-conductive coating layer. The proportion of the electrode active material in the electrode mixture is not particularly limited, but is, for example, 60 mass % or more and 90 mass % or less.

[0119] 4. Electrode Mixture The electrode mixture may further contain at least one of a conductive aid and a binder, if necessary.

[0120] Examples of the conductive additive include carbon materials, metal particles, and conductive polymers. Examples of the carbon material include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as carbon fibers, carbon nanotubes (CNT), and carbon nanofibers (CNF). The proportion of the conductive additive in the electrode mixture is, for example, 0.01% by mass or more and 10% by mass or less.

[0121] Examples of binders include rubber-based binders such as butadiene rubber (BR), acrylate butadiene rubber (ABR), and styrene butadiene rubber (SBR), as well as fluorine-containing binders such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), etc. The proportion of the binder in the electrode mixture is, for example, 0.01% by mass or more and 5% by mass or less.

[0122] The electrode mixture may contain an electrolyte other than the sulfide solid electrolyte described above. Examples of the electrolyte include those described in "2. Electrolyte Layer" below. The electrode mixture may be a negative electrode mixture or a positive electrode mixture.

[0123] B. Battery Figure 2 is a schematic cross-sectional view illustrating a battery according to the present disclosure. The battery 20 shown in Figure 2 includes a positive electrode active material layer 11, a negative electrode active material layer 12, and an electrolyte layer 13 disposed between the positive electrode active material layer 11 and the negative electrode active material layer 12. The battery 20 also includes a positive electrode current collector 14 that collects electrons from the positive electrode active material layer 11, and a negative electrode current collector 15 that collects electrons from the negative electrode active material layer 12. In particular, in the battery 20 according to the present disclosure, at least one of the positive electrode active material layer 11 and the negative electrode active material layer 12 contains the above-described electrode mixture.

[0124] According to the present disclosure, at least one of the positive electrode active material layer and the negative electrode active material layer contains the above-described electrode mixture, resulting in a battery in which an increase in resistance is suppressed.

[0125] 1. Positive Electrode Active Material Layer and Negative Electrode Active Material Layer The positive electrode active material layer is a layer containing at least a positive electrode active material, and preferably contains the above-described electrode mixture. By using the above-described electrode mixture, oxidation of the sulfide solid electrolyte in the positive electrode active material layer can be effectively suppressed. The electrode mixture is the same as that described in "A. Electrode Mixture." The thickness of the positive electrode active material layer is not particularly limited, but is, for example, 0.1 μm or more and 1000 μm or less.

[0126] The negative electrode active material layer is a layer containing at least a negative electrode active material, and preferably contains the above-described electrode mixture. By using the above-described electrode mixture, reduction of the sulfide solid electrolyte in the negative electrode active material layer can be effectively suppressed. The electrode mixture is the same as that described in "A. Electrode Mixture." The thickness of the negative electrode active material layer is not particularly limited, but is, for example, 0.1 μm or more and 1000 μm or less.

[0127] 2. Electrolyte Layer The electrolyte layer is a layer disposed between the positive electrode active material layer and the negative electrode active material layer, and contains at least an electrolyte. The electrolyte layer may also contain a binder as needed. The binder is the same as that described in "A. Electrode Mixture."

[0128] The electrolyte may be a liquid electrolyte (electrolytic solution) or a solid electrolyte. Generally, an electrolyte layer containing a solid electrolyte is called a solid electrolyte layer, and a battery having a solid electrolyte layer is called a solid-state battery. The solid-state battery may be a semi-solid battery or an all-solid-state battery. When the solid electrolyte layer in a solid-state battery contains only an inorganic solid electrolyte as the electrolyte, as described below, the solid-state battery is called an all-solid-state battery.

[0129] The electrolyte may be any known electrolyte used in batteries. ６ Examples of suitable electrolytes include those containing lithium salts such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) and non-aqueous solvents such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC). When the electrolyte contains an electrolytic solution, the electrolyte layer may be a separator impregnated with the electrolytic solution. The separator may be a conventionally known material.

[0130] Examples of solid electrolytes include inorganic solid electrolytes such as sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, halide solid electrolytes, and complex hydrides. Among these, sulfide solid electrolytes are particularly preferred because of their high ionic conductivity. The sulfide solid electrolyte is the same as that described in "A. Electrode mixture." The electrolyte layer may contain a sulfide solid electrolyte that does not contain a P element. Examples of sulfide solid electrolytes that do not contain a P element include Li ２ S-SiS ２ , Li ２ S-SiS ２ - LiI, Li ２ S-SiS ２ - LiBr, Li ２ S-SiS ２ -LiCl, Li ２ S-SiS２ -B ２ S ３ - LiI, Li ２ S-B ２ S ３ and Li ２ S-SiS ２ -Li ｘ MO ｙ (where x and y are positive numbers, and M is any of Si, Ge, B, Al, Ga, and In.) Oxide solid electrolytes, nitride solid electrolytes, and halide solid electrolytes usually contain oxygen (O), nitrogen (N), and halogen (X), respectively, as the main anion element components.

[0131] The solid electrolyte may also include organic solid electrolytes such as polymer electrolytes and gel electrolytes.

[0132] Here, the electrolyte layer may contain the sulfide solid electrolyte and organic compound described in "A. Electrode Composite." That is, the present disclosure can also provide an electrolyte layer composite containing a sulfide solid electrolyte containing lithium, sulfur, and phosphorus, and an organic compound, wherein the organic compound has two or more benzene rings. The electrolyte layer composite is similar to the content described in "A. Electrode Composite" except that it does not contain an electrode active material or a conductive additive. It is preferable that at least a portion of the organic compound is present on the surface of the sulfide solid electrolyte in the electrolyte layer composite. The thickness of the electrolyte layer is not particularly limited, but is, for example, 0.1 μm or more and 1000 μm or less.

[0133] 3. Other Configurations The battery according to the present disclosure typically includes a positive electrode current collector and a negative electrode current collector. Examples of materials for the positive electrode current collector include stainless steel, aluminum, nickel, iron, titanium, and carbon. Examples of materials for the negative electrode current collector include stainless steel, copper, nickel, and carbon.

[0134] The battery according to the present disclosure may also include an exterior body that houses the above-described components. Examples of the exterior body include a laminate-type exterior body and a case-type exterior body. The battery according to the present disclosure may also include a restraining jig that applies a restraining pressure in the thickness direction to the above-described components. A known jig can be used as the restraining jig. The restraining pressure may be, for example, 0.1 MPa or more and 50 MPa or less, or 1 MPa or more and 20 MPa or less.

[0135] 4. Battery The battery in the present disclosure may be a liquid-based battery in which the electrolyte layer contains an electrolytic solution, or a solid-state battery in which the electrolyte layer contains a solid electrolyte. As described above, the solid-state battery may be a semi-solid-state battery or an all-solid-state battery.

[0136] The type of battery in the present disclosure is not particularly limited, but is typically a lithium-ion battery. The battery in the present disclosure may be a primary battery or a secondary battery, but a secondary battery is preferred because it can be repeatedly charged and discharged and is useful, for example, as an in-vehicle battery.

[0137] The use of the battery in the present disclosure is not particularly limited, but examples include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the battery is preferably used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery in the present disclosure may also be used as a power source for mobile objects other than vehicles (e.g., trains, ships, and aircraft), or as a power source for electrical appliances such as information processing devices.

[0138] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure.

[0139] Example 1-1 A test battery (all-solid-state battery) was fabricated as follows, using the electrode mixture according to the present disclosure in the negative electrode active material layer.

[0140] (Preparation of Sulfide Solid Electrolyte) Under a nitrogen atmosphere, 0.59 g of lithium sulfide, 0.95 g of diphosphorus pentasulfide, 0.19 g of lithium bromide, and 0.28 g of lithium iodide were introduced into a Schlenk flask (volume: 100 mL) equipped with a stirrer. After rotating the stirrer, 20 mL of a complexing agent (tetramethylethylenediamine: TMEDA) was added, and stirring was continued for 12 hours to obtain a complex-containing material. The obtained complex-containing material was dried under vacuum at room temperature (23°C) to obtain a powdered complex. Next, the complex powder was heated under vacuum at 120°C for 2 hours to obtain an amorphous sulfide solid electrolyte. Furthermore, the amorphous sulfide solid electrolyte was heated under vacuum at 140°C for 2 hours to obtain a crystalline sulfide solid electrolyte. The ionic conductivity (25°C) of the obtained crystalline sulfide solid electrolyte was measured by an impedance method and was found to be 4.1 mS / cm.

[0141] (Preparation of Positive Electrode) Positive electrode active material (LiNi １／３ Co １／３ Mn １／３ O ２ 80.0 g of the sulfide solid electrolyte, 9.51 g of the sulfide solid electrolyte, and 2.5 g of a conductive additive (VGCF; manufactured by Showa Denko K.K.) were placed in a Filmix container. Then, a binder (a solution containing styrene butadiene rubber; the binder concentration in the solution was 5% by mass relative to the total solution) and 32.21 g of a solvent (tetralin) were added to the Filmix container and kneaded. This resulted in a positive electrode slurry with a solids concentration of 69% by mass. The positive electrode slurry was applied in the form of a film to the surface of a positive electrode current collector (aluminum foil) using a blade coating method with an applicator and heated at 100 °C for 30 minutes. This resulted in a positive electrode having a positive electrode current collector and a positive electrode active material layer.

[0142] (Preparation of Negative Electrode) 18.6 g of negative electrode active material (Si simple substance), 8.69 g of the sulfide solid electrolyte, 0.05 g of an organic compound represented by the above chemical formula (1) (organic compound A: 9,9-Bis(4-glycidyloxyphenyl)fluorene) as an additive, a binder (a solution containing styrene butadiene rubber; the binder concentration in the solution was 5% by mass relative to the total solution), and a solvent (diisobutyl ketone) were added to a FILMICS container and kneaded. This resulted in a negative electrode slurry (negative electrode composite) with a solids concentration of 43% by mass. In the negative electrode slurry, the ratio of the organic compound to the sulfide solid electrolyte was 0.58% by mass. The peripheral speed during kneading was in the range of 5 m / s to 30 m / s. A high-shear PC wheel was used for the FILMICS. The negative electrode slurry was applied in the form of a film onto the surface of a negative electrode current collector (nickel foil) by a blade coating method using an applicator, and the resultant was heated at 100° C. for 30 minutes, thereby obtaining a negative electrode having a negative electrode current collector and a negative electrode active material layer.

[0143] (Preparation of Solid Electrolyte Layer) 40 g of the sulfide solid electrolyte was mixed with 8.00 g of a solution containing acrylate butadiene rubber and hexane (the concentration of the acrylate butadiene rubber in the solution was 5% by mass relative to the total solution), 25.62 g of heptane, and 8.00 g of dibutyl ether, and the mixture was kneaded using an ultrasonic homogenizer. This produced a slurry for the solid electrolyte layer. The slurry was applied to the surface of a substrate (aluminum foil) in the form of a film using a blade coating method with an applicator, and heated at 100°C for 30 minutes. This produced a transfer member having a substrate and a solid electrolyte layer.

[0144] (Preparation of Evaluation Battery) Using the above-described components, a laminate having a negative electrode, a solid electrolyte layer, and a positive electrode in this order was obtained. The solid electrolyte layer and the positive electrode were each transferred using a pressure of 20 kN. The obtained laminate was pressed using a roll press. The press linear pressure was 4 ton / cm, and the gap between the rolls was 130 μm. In this way, an evaluation battery (all-solid-state battery) was prepared. The design capacity of the battery was 0.3 Ah.

[0145] Examples 1-2 to 1-12 and Comparative Examples 1-1 to 1-7 Evaluation batteries were fabricated in the same manner as in Example 1-1, except that negative electrodes were fabricated by changing the types and amounts of organic compounds as shown in Table 1. Organic compound B in Table 1 is 1,3-diphenyl-2,3-epoxy-1-propanone, represented by the above chemical formula (2). Organic compound E in Table 1 is 5,12-dioxahexacyclohexadecane, represented by the following chemical formula (5).

[0146]

[0147] Example 2-1 A test battery (all-solid-state battery) was fabricated as follows, using the electrode mixture according to the present disclosure in the positive electrode active material layer.

[0148] (Fabrication of Positive Electrode) A crystalline sulfide solid electrolyte was fabricated in the same manner as in Example 1-1. A positive electrode was fabricated using this sulfide solid electrolyte as follows. １／３ Co １／３ Mn １／３ O ２ 80.0 g of the sulfide solid electrolyte, 9.51 g of the sulfide solid electrolyte, 0.05 g of an organic compound represented by the chemical formula (1) (A: 9,9-Bis(4-glycidyloxyphenyl)fluorene) as an additive, and 2.5 g of a conductive additive (VGCF; manufactured by Showa Denko K.K.) were placed in a FILMICS container. Then, 32.21 g of a binder (a solution containing styrene butadiene rubber; the binder concentration in the solution was 5% by mass relative to the total solution) and a solvent (tetralin) were added to the FILMICS container and kneaded. This resulted in a positive electrode slurry with a solids concentration of 69% by mass. In the positive electrode slurry (positive electrode composite), the ratio of the organic compound to the sulfide solid electrolyte was 0.53% by mass. The positive electrode slurry was applied in the form of a film onto the surface of a positive electrode current collector (aluminum foil) by a blade coating method using an applicator, and the resulting film was heated at 100° C. for 30 minutes, thereby obtaining a positive electrode having a positive electrode current collector and a positive electrode active material layer.

[0149] (Preparation of Negative Electrode) 18.6 g of negative electrode active material (Si simple substance), 8.69 g of the above sulfide solid electrolyte, a binder (a solution containing styrene butadiene rubber; the binder concentration in the solution was 5% by mass relative to the total solution), and a solvent (diisobutyl ketone) were added to a FILMICS container and kneaded. As a result, a negative electrode slurry with a solids concentration of 43% by mass was obtained. The peripheral speed during kneading was in the range of 5 m / s to 30 m / s. A high-shear PC wheel was used for the FILMICS. The negative electrode slurry was applied in the form of a film to the surface of a negative electrode current collector (nickel foil) by a blade coating method using an applicator, and the mixture was heated at 100°C for 30 minutes. As a result, a negative electrode having a negative electrode current collector and a negative electrode active material layer was obtained.

[0150] (Preparation of Test Battery) A test battery was prepared in the same manner as in Example 1-1, except that the above positive electrode and negative electrode were used.

[0151] Examples 2-2 to 2-12 and Comparative Examples 2-1 to 2-13 Evaluation batteries were fabricated in the same manner as in Example 2-1, except that the positive electrodes were fabricated by changing the types and amounts of additives (organic compounds) as shown in Table 2. Organic compound F in Table 2 is 2-Ethylhexylglycidylether, which is represented by the following chemical formula (6). Organic compounds A, B, and E are the same as those in Table 1.

[0152]

[0153] [Evaluation] Charge-discharge tests and XPS measurements were performed on the all-solid-state batteries fabricated in Examples 1-1 to 1-12, Comparative Examples 1-1 to 1-7, Examples 2-1 to 2-12, and Comparative Examples 2-1 to 2-13. Specifically, the tests were as follows.

[0154] <Charge / Discharge Test> A cycle test was carried out using each of the prepared all-solid-state batteries as follows. First, CCCV charge / discharge was carried out for 4 cycles at 0.1 C with an upper limit voltage of 4.25 V and a lower limit voltage of 2.87 V. The resistance value after 4 cycles was recorded as the initial resistance (Ω cm ２ Then, CCCV charge / discharge with an upper limit voltage of 4.25 V and a lower limit voltage of 2.87 V was performed for 100 cycles at 1 / 3 C. The resistance value (Ω cm) after 100 cycles was measured.２ ) was measured. The resistance increase rate was calculated using the following formula. The results are shown in Tables 1 and 2. Representative results for an evaluation battery fabricated using an electrode mixture according to the present disclosure in the negative electrode active material layer and an evaluation battery fabricated using an electrode mixture according to the present disclosure in the positive electrode active material layer are summarized in Figures 3 and 4. Resistance increase rate (%) = [(resistance after 100 cycles - initial resistance) / (initial resistance)] x 100

[0155] <XPS Measurement> XPS measurement was performed on the electrode before charge / discharge and after 100 cycles under the following conditions to obtain 2p spectra for S and P. Equipment used: Versa Probe III (ULVAC-PHI) X-ray source used: mono-AlKα ray (hν=1486.6 eV), photoelectron take-off angle: 45°, X-ray beam diameter: 100 μmΦ, analysis position: 500 μm × 300 μm at the center of the sample

[0156] In Examples 1-4 and 1-9 and Comparative Examples 1-1 and 1-4, the negative electrode active material layer was measured, and the S element and the P element were measured. ４ ３－ The deterioration of the sulfide solid electrolyte was evaluated based on the abundance ratio of P. In addition, for Examples 2-3, 2-9, and 2-12 and Comparative Examples 2-4 and 2-10, the positive electrode active material layer was measured. ４ ３－ and PO Ｘ The deterioration of the sulfide solid electrolyte was evaluated based on the abundance ratio of each of the sulfide solid electrolytes. The results are shown in Tables 1 and 2. Representative results for the negative electrode active material layer (the results of Examples 1-4 and Comparative Example 1-1) are summarized in FIGS. 5 and 6 along with the abundance ratios of other structures. Representative results for the positive electrode active material layer (Examples 2-3 and Comparative Example 2-1) are also summarized in FIG. 7.

[0157]

[0158]

[0159] As shown in Tables 1 and 2 and Figures 3 and 4, the resistance increase rate was significantly reduced in the battery using the electrode mixture of the present disclosure. For example, as shown in Table 1, Figures 5(a) and 5(b) and Figures 6(a) and 6(b), in the examples, the ortho-composition PS ４ ３－ is sufficiently maintained even after cycling, and the product of the reduction reaction, Li ２ S and Li ３ This is thought to be because the proportion of P was low, and the reduction reaction of the sulfide solid electrolyte was suppressed. Similarly, as shown in Figures 7(a) and 7(b), in the examples, ４ ３－ is sufficiently maintained even after cycling, and PO, which is a product of the oxidation reaction, Ｘ This is thought to be because the generation of sulfide solid electrolyte was suppressed, and the oxidation reaction of the sulfide solid electrolyte was suppressed. Thus, it was confirmed that the electrode mixture according to the present disclosure can suppress the deterioration of the sulfide solid electrolyte and the increase in battery resistance.

[0160] Examples 3-1 to 3-12 Evaluation batteries were fabricated in the same manner as in Example 1-1, except that negative electrodes were fabricated by changing the types and amounts of organic compounds as shown in Table 3. Organic compound C in Table 3 is tetraglycidyl-3,3'-diaminodiphenylsulfone represented by the above chemical formula (3), and organic compound D in Table 3 is a diglycidyl ether sulfone-based compound represented by the above chemical formula (4).

[0161] Examples 4-1 to 4-12 Evaluation batteries were fabricated in the same manner as in Example 2-1, except that positive electrodes were fabricated by changing the types and amounts of organic compounds as shown in Table 4. Organic compounds C and D in Table 4 are the same as organic compounds C and D in Table 3.

[0162] [Evaluation] Charge-discharge tests and XPS measurements were performed on the all-solid-state batteries fabricated in Examples 3-1 to 3-12 and Examples 4-1 to 4-12. The specific measurement methods were the same as those described above. The results are shown in Tables 3 and 4.

[0163]

[0164]

[0165] As shown in Table 3 and FIG. 8, the batteries fabricated in Examples 3-1 to 3-12 had a lower resistance increase rate than the batteries fabricated in Comparative Examples 1-1 to 1-7 described above. Furthermore, the batteries fabricated in Examples 3-1 to 3-12 had a lower resistance increase rate than the batteries fabricated in Examples 1-1 to 1-12 described above. Furthermore, as shown in Table 4 and FIG. 9, the batteries fabricated in Examples 4-1 to 4-12 had a lower resistance increase rate than the batteries fabricated in Comparative Examples 2-1 to 2-13 described above. Furthermore, the batteries fabricated in Examples 4-1 to 4-12 had a lower resistance increase rate than the batteries fabricated in Examples 2-1 to 2-12 described above.

[0166] 1...Electrode active material 2...Sulfide solid electrolyte 3...Organic compound 10...Electrode mixture 11...Positive electrode active material layer 12...Negative electrode active material layer 13...Electrolyte layer 14...Positive electrode current collector 15...Negative electrode current collector 20...Battery

Claims

1. An electrode mixture comprising an electrode active material, a sulfide solid electrolyte containing lithium, sulfur, and phosphorus, and an organic compound, wherein the organic compound has two or more benzene rings, and at least a portion of the organic compound is present between the electrode active material and the sulfide solid electrolyte.

2. The electrode mixture according to claim 1, containing at least one of a compound represented by the following general formula (1) or the following general formula (2) as the organic compound: (In the formula, R １ and R ２ are each independently an organic group, and R ３ ~R １０ are each independently a hydrogen atom or a substituent, and n is an integer of 0 to 4.

3. The above R １ and the R ２ The electrode mixture according to claim 2 , wherein at least one of the above is an organic group represented by the following general formula (3): (In the formula, X represents an organic group, and * represents a bond.) 4. The electrode mixture according to claim 3, wherein X has an epoxy group.

5. The electrode mixture according to claim 1, wherein the organic compound contains 9,9-bis(4-glycidyloxyphenyl)fluorene represented by the following chemical formula (1):

6. The electrode mixture according to claim 1, containing a compound represented by the following general formula (4) as the organic compound: (wherein S is an organic group, n is 0 or 1, and R １１ ~R ２０ are each independently a hydrogen atom or a substituent.

7. The electrode mixture according to claim 6, wherein said S has an epoxy group.

8. The electrode mixture according to claim 7, wherein S is an organic group represented by the following general formula (5): (wherein T and U are each independently an organic group; n １ and n ２ are each independently 0 or 1, and * represents a bond.

9. The electrode mixture according to claim 1, wherein the organic compound contains 1,3-diphenyl-2,3-epoxy-1-propanone represented by the following chemical formula (2):

10. The electrode mixture according to claim 1, wherein the organic compound has a sulfonyl group.

11. The electrode mixture according to claim 10, containing a compound represented by the following general formula (6) as the organic compound: (In the formula, R ２１ ~R ３０ are each independently a hydrogen atom, a substituent, or an organic group.

12. The above R ２１ ~ The above R ３０ The electrode mixture according to claim 11, wherein at least one of the above is an organic group represented by the following general formula (7) or the following general formula (8): (wherein α and β each independently represent an organic group, n １ and n ２ are each independently 0 or 1, and * represents a bond.

13. The electrode mixture according to claim 1, wherein the organic compound contains tetraglycidyl-3,3'-diaminodiphenylsulfone represented by the following chemical formula (3):

14. The above R ２１ ~ The above R ３０ The electrode mixture according to claim 11, wherein at least one of the above is an organic group represented by the following general formula (9): (In the formula, γ represents an organic group, n represents 0 or 1, and * represents a bond.) 15. The electrode mixture according to claim 1, wherein the organic compound contains a diglycidyl ether sulfone compound represented by the following chemical formula (4):

16. The electrode mixture according to claim 1, wherein the organic compound has a structure represented by the following structural formula (1), a structure represented by the following structural formula (2), a structure in which at least one hydrogen atom bonded to the benzene ring of the following structural formula (1) is substituted with a group having a molecular weight of 30 or less, or a structure in which at least one hydrogen atom bonded to the benzene ring of the following structural formula (2) is substituted with a group having a molecular weight of 30 or less. (In the formula, * represents a bond, and n is an integer of 0 to 4.) 17. The electrode mixture according to claim 1, wherein the organic compound has a structure represented by the following structural formula (3-1), a structure represented by the following structural formula (3-2), a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (3-1) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (3-2) is substituted with a group having a molecular weight of 50 or less. (In the formula, * means a bond.) 18. The electrode mixture according to claim 1, wherein the organic compound has a structure represented by the following structural formula (4-1), a structure represented by the following structural formula (4-2), a structure represented by the following structural formula (4-3), a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-1) is substituted with a group having a molecular weight of 50 or less, a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-2) is substituted with a group having a molecular weight of 50 or less, or a structure in which at least one hydrogen bonded to the benzene ring of the following structural formula (4-3) is substituted with a group having a molecular weight of 50 or less. (In the formula, * means a bond.) 19. The value of the Hansen solubility parameter of the organic compound is 8.0 MPa. ０．５ The electrode mixture according to claim 1 .

20. The electrode mixture according to claim 1, wherein the ratio of the organic compound to the sulfide solid electrolyte is greater than 0.50 mass % and less than 14.0 mass %.

21. The electrode mixture of claim 1, wherein the electrode mixture is a negative electrode mixture.

22. The electrode mixture according to claim 21, wherein the electrode active material is a Si-based active material.

23. The electrode mixture of claim 1, wherein the electrode mixture is a positive electrode mixture.

24. The electrode mixture according to claim 23, wherein the electrode active material is an oxide active material containing at least Ni and Co elements.

25. A battery having a positive electrode active material layer, a negative electrode active material layer, and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein at least one of the positive electrode active material layer and the negative electrode active material layer contains the electrode mixture described in any one of claims 1 to 24.

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