Negative electrode material, negative electrode and battery

Abstract

This negative electrode material contains a negative electrode active material and a solid electrolyte material, the solid electrolyte material containing an alkali metal element, a metal element or metalloid element other than the alkali metal element, and a halogen element, and the metal element or metalloid element other than the alkali metal element contains at least one of Zr and In.

Description

Technical Field

[0001] The present disclosure relates to a negative electrode material, a negative electrode, and a battery. Background Art

[0002] In recent years, solid electrolytes have attracted attention as electrolytes used in electrochemical devices such as lithium ion batteries. Since solid electrolytes are excellent in high-temperature durability, high-voltage tolerance, etc. compared with conventional electrolytic solutions, they are considered useful for improving battery performance such as safety, high capacity, rapid charge and discharge, and battery pack energy density.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: International Publication No. 2019 / 146295 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Here, in order to improve ionic conductivity, a solid electrolyte is sometimes included in the negative electrode of a battery. However, conventional negative electrode materials containing a solid electrolyte sometimes cannot stably perform charge and discharge.

[0008] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a negative electrode material having good charge and discharge characteristics, and a negative electrode and a battery including such a negative electrode material.

[0009] Means for Solving the Problems

[0010] The present disclosure includes the following embodiments [1] to [9].

[0011] [1] A negative electrode material comprising a negative electrode active material and a solid electrolyte material,

[0012] wherein the solid electrolyte material contains an alkali metal element, a metal element other than an alkali metal element or a metalloid element, and a halogen element,

[0013] and the metal element other than an alkali metal or the metalloid element contains at least one of Zr and In.

[0014] [2] The negative electrode material according to [1], wherein the solid electrolyte material contains a compound represented by A α M β Z γ D ζ O η

[0015] In the formula, A is an alkali metal element, M is at least one of Zr and In, Z is a halogen element, D is at least one of P and S, 1.6 ≤ α ≤ 3.5, 0 < β ≤ 1.2, 3 ≤ γ ≤ 6.5, 0 ≤ ζ ≤ 0.5, and 0 ≤ η ≤ 2.

[0016] [3] The negative electrode material according to [1] or [2], wherein the volume ratio of the above-mentioned negative electrode active material to the total volume of the above-mentioned negative electrode active material and the above-mentioned solid electrolyte material is 0.30 to 0.90.

[0017] [4] The negative electrode material according to any one of [1] to [3], wherein the above-mentioned negative electrode active material is an oxide containing titanium.

[0018] [5] The negative electrode material according to any one of [1] to [4], which further contains an ionic liquid.

[0019] [6] The negative electrode material according to any one of [1] to [5], wherein in the above-mentioned solid electrolyte material, the total amount of Zr and In is more than the total amount of the alkali metal element, the metal element or the metalloid element other than Zr and In.

[0020] [7] The negative electrode material according to any one of [1] to [6], wherein in the above-mentioned solid electrolyte material, the content of Y in terms of the amount of substance is less than the total amount of Zr and In.

[0021] [8] A negative electrode comprising the negative electrode material according to any one of [1] to [7].

[0022] [9] A battery comprising the negative electrode according to [8].

[0023] Advantages of the Invention

[0024] According to the present disclosure, it is possible to provide a negative electrode material having good charge and discharge characteristics, and a negative electrode and a battery including such a negative electrode material. Description of the Drawings

[0025] Figure 1 It is a graph showing the results (the first cycle and the second cycle) of the charge and discharge test of the secondary battery of Example 1.

[0026] Figure 2 It is a graph showing the results (the third cycle and the fourth cycle) of the charge and discharge test of the secondary battery of Example 1.

[0027] Figure 3 It is a graph showing the results of the charge and discharge test of the secondary battery of Example 2.

[0028] Figure 4 It is a graph showing the results of the charge and discharge test of the secondary battery of Example 3.

[0029] Figure 5 It is a graph showing the results of charge and discharge tests of the secondary battery of Example 4.

[0030] Figure 6 It is a graph showing the results of charge and discharge tests of the secondary battery of Example 5. Detailed implementation mode

[0031] The negative electrode material of the present embodiment mode includes a negative electrode active material and a solid electrolyte material. The solid electrolyte material includes an alkali metal element, a metal element or a metalloid element other than the alkali metal element, and a halogen. The metal element or the metalloid element other than the alkali metal element may include at least one of Zr and In.

[0032] As the negative electrode active material, it can be a material that is charged and discharged at 0.5 V or more based on Li / Li + As a reference, substances can include simple substances of elements such as alkali metal elements, Si, P, Sn, In, Au, etc., alloys or complexes containing alkali metal elements, Si, P, Sn, In, Au, etc. such as Li-In, Si-Mn, Si-Co, Si-Ni, carbon materials such as graphite, substances in which alkali metal ions are intercalated between the layers of the carbon material, and oxides containing titanium. The alkali metal element can be Li, Na or K, can be Li or Na, and can be Li. The negative electrode active material may include one or more selected from alkali metal elements; simple substances of elements such as Si, P, Sn, In or Au; alloys or complexes containing alkali metal elements and one or more elements selected from Si, P, Sn, In and Au; and oxides containing titanium.

[0033] As the titanium-containing oxide, it can be a compound represented by the composition formula: A s TiO t Shown (A is an alkali metal element, s≥0). Among them, the alkali metal element A can be Li, Na or K, can be Li or Na, and can be Li. In the above composition formula, s can be 0.1 to 2, can be 0.3 to 1.5, and can be 0.5 to 1. In the above composition formula, t can be 2 to 3, or can be 2.2 to 2.8. Specifically, as the oxide containing titanium, A 4 Ti 5 O 12 (A is an alkali metal, which can be Li).

[0034] The content of the negative electrode active material in the negative electrode material (or negative electrode) can be 50% by mass or more, can be 60% by mass or more, and can be 70% by mass or more with respect to the total amount of the negative electrode material. The content of the negative electrode active material in the negative electrode material can be 99% by mass or less, can be 95% by mass or less, and can be 90% by mass or less with respect to the total amount of the negative electrode material. Additionally, the content of the negative electrode active material in the negative electrode material can be 50 to 99% by mass, can be 60 to 95% by mass, and can be 70 to 90% by mass with respect to the total amount of the negative electrode material. The volume ratio of the negative electrode active material to the total volume of the negative electrode active material and the solid electrolyte material can be 0.30 to 0.90. The volume ratio of the solid electrolyte to the total volume of the negative electrode active material and the solid electrolyte material can be 0.30 to 0.90, can be 0.30 to 0.70, can be 0.35 to 0.70, can be 0.40 to 0.70, can be greater than 0.50 and 0.70 or less, and can be 0.53 to 0.70. The volume ratio of the solid electrolyte to the total volume of the negative electrode active material and the solid electrolyte material can be 0.30 or more, can be 0.30 or more, can be 0.35 or more, can be 0.40 or more, can be greater than 0.50, and can be 0.53 or more. Additionally, the content of the solid electrolyte material in the negative electrode material can be 30 to 90% by mass, can be 30 to 70% by mass, and can be 35 to 70% by mass with respect to the total amount of the negative electrode active material and the solid electrolyte.

[0035] The negative electrode material contains a solid electrolyte material (halide-based solid electrolyte) containing an alkali metal element, a metal element other than an alkali metal element or a metalloid element, and a halogen element. Hereinafter, the solid electrolyte material containing an alkali metal element, a metal element other than an alkali metal element or a metalloid element, and a halogen element is also referred to as the first solid electrolyte material. The first solid electrolyte material can satisfy at least one of the following (A) to (C). (A) The first solid electrolyte material contains In as a metal element other than an alkali metal element. (B) The first solid electrolyte material contains Zr as a metal element other than an alkali metal element and contains two or more halogen elements. (C) The first solid electrolyte material further contains an oxygen element.

[0036] The alkali metal element contained in the first solid electrolyte material can be any one of Li, Na, K, Rb, and Cs, can contain at least one of Li, Na, and K, can contain at least one of Li and Na, and can contain Li.

[0037] The proportion of one alkali metal element among the alkali metal elements contained in the first solid electrolyte material may be 80 mol% or more, may be 90 mol% or more, and may be 95 mol% or more. This one alkali metal element may be at least one of Li, Na, and K, may be at least one of Li and Na, and may be Li.

[0038] The content of the alkali metal element in the first solid electrolyte material may be 15 to 30 mol%, may be 18 to 28 mol%, and may be 20 to 27 mol% based on the total amount of atoms contained in the first solid electrolyte material.

[0039] There is no particular limitation on the metal element or metalloid element other than the alkali metal element. Elements with a valence of 2 to 5 can be cited, and one or more elements selected from elements with a valence of 3 and elements with a valence of 4 may be included. The first solid electrolyte material may contain one or two or more metal elements or metalloid elements other than the alkali metal element.

[0040] As the element with a valence of 2, alkaline earth metals, Zn, etc. can be cited. As the alkaline earth metal, it may be at least one of Mg, Ca, Sr, and Ba, may be at least one of Mg and Ca, and may be Mg. As the metal element with a valence of 3, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, Al, Ga, In, Bi, and Sb can be cited. As the element with a valence of 4, Zr, Ti, Hf, Sn, etc. can be cited, and may be Zr. As the metal element with a valence of 5, Nb, Ta, etc. can be cited. In addition, as the element with a valence of 6 or more, W can be cited.

[0041] The metal element or metalloid element other than the alkali metal element may contain at least one of In and Zr. The content of the metal element or metalloid element other than the alkali metal element in the first solid electrolyte material is preferably 8 to 15 mol%, more preferably 8 to 13 mol%, and further preferably 9 to 12 mol% based on all the elements contained in the first solid electrolyte material.

[0042] In the first solid electrolyte material, the total amount of Zr and In may be more than the total amount of the alkali metal element, the metal element other than Zr and In, or the metalloid element. It should be noted that when the first solid electrolyte material contains only either Zr or In, this total amount is the content of the contained element. The total amount of Zr and In in the first solid electrolyte material may be 60 mol% or more, may be 70 mol% or more, may be 80 mol% or more, and may be 90 mol% or more of the total amount of the metal element or metalloid element other than the alkali metal element.

[0043] In the first solid electrolyte material, the content of Y in terms of the amount of substance may be less than the total amount of substance of Zr and In. It should be noted that in the case where the first solid electrolyte material contains only either Zr or In, the total amount of substance is the content of the contained element. The content of Y in the first solid electrolyte may be 40 mol% or less, may be 30 mol% or less, may be 20 mol% or less, may be 10 mol% or less, relative to the total amount of substance of metal elements or metalloid elements other than alkali metal elements. The first solid electrolyte material may substantially contain no Y.

[0044] The first solid electrolyte material may contain 70 mol% or more of one element among metal elements or metalloid elements other than alkali metal elements, may contain 75 mol% or more, may contain 80 mol% or more, relative to the total amount of metal elements or metalloid elements other than alkali metal elements. In this case, as this one element, it may be an element with a valence of 3 or 4, may be In or Zr. The first solid electrolyte material may contain 70 mol% or more of In, may contain 75 mol% or more, may contain 80 mol% or more, relative to the total amount of metal elements or metalloid elements other than alkali metal elements. In this case, the first solid electrolyte material contains a metal element or a metalloid element other than alkali metal elements other than this one element (also referred to as doping element X1). The doping element X1 is an element different from the above one element. When the above one element is an element with a valence of 3, the doping element X1 may be at least one element selected from Zr, Sn, Ti, Nb, Ta, Bi, and Y, may be at least one element selected from Zr, Sn, Nb, and Ta. When the above one element is an element with a valence of 4, the doping element X1 may be at least one element selected from Bi, Al, Ga, In, Sc, Sm, Sb, La, Zn, Sn, and alkaline earth metals, may be at least one element selected from Bi, La, Zn, and Sn.

[0045] The halogen element contained in the first solid electrolyte material of this embodiment may be any one of F, Cl, Br, and I, may contain at least one of Cl, Br, and I, may contain at least one of Cl and Br, may contain Cl. The ionic conductive substance may also contain only one halogen element, but may also contain two or more halogen elements. When the first solid electrolyte material contains Zr as a metal element other than alkali metal elements, the first solid electrolyte material may contain two or more halogen elements, may contain Cl and a halogen element other than Cl, may contain Cl and Br. The content of the halogen element other than Cl or Br may be 10 mol% or less, may be 0.1 - 10 mol%, may be 1 - 8 mol%, relative to the total amount of halogen elements contained in the solid electrolyte material.

[0046] The content of the halogen element in the first solid electrolyte material is preferably 40 to 70 mol%, more preferably 45 to 68 mol%, based on all the elements contained in the halogen element.

[0047] Relative to the total amount of the halogen element, the first solid electrolyte material may contain 80 mol% or more of one element in the halogen element, may contain 85 mol% or more, may contain 90 mol% or more. This one halogen element may be Cl or Br, and may be Cl. In this case, the first solid electrolyte material contains a halogen element other than this one halogen element (also referred to as the doping element X2). When this one halogen element is Cl, the doping element X2 may be at least one of Br and I, and may be Br.

[0048] The first solid electrolyte material may contain at least one of P and S (also referred to as the doping element X3). The content of the doping element X3 in the first solid electrolyte material may be 0.05 to 5 mol%, may be 0.1 to 3 mol%, may be 0.2 to 2 mol%, may be 0.3 to 1 mol%, relative to the total amount of atoms contained in the first solid electrolyte material.

[0049] When the first solid electrolyte material contains at least one of P and S, the first solid electrolyte material may contain a tetravalent metal element or a metalloid element. Examples of the tetravalent metal element or metalloid element include Zr, Ti, Hf, etc., and may be Zr. In addition, as the doping element X2, it may contain at least one of Hf and Mg.

[0050] The content of the doping element X3 in the first solid electrolyte material may be 50 mol% or less, may be 1 to 30 mol%, may be 1 to 20 mol%, may be 2 to 10 mol%, of the content of the tetravalent metal element or the metalloid element. The content of the doping element X in the first solid electrolyte material may be 20 mol% or less, may be 15 mol% or less, may be 10 mol% or less, may be 8 mol% or less, of the content of the tetravalent metal element or the metalloid element.

[0051] The first solid electrolyte material may have a hexagonal crystal structure, or may have a crystal structure belonging to the space group P6 3 mc. The solid electrolyte material having a hexagonal crystal structure may contain at least one element selected from Sc, La, Y, Ga, In, Bi, Sb, Ge, Zr, Sn, Nb, and Ta, and may contain Sc.

[0052] The first solid electrolyte material may contain a compound represented by the following formula (A).

[0053] A α M βZ γ D ζ O η (A)

[0054] Among them, A is an alkali metal, M is a metal element or a metalloid element other than an alkali metal element, Z is a halogen element, D is at least one of P and S, 1.6 ≤ α ≤ 3.5, 0 < β ≤ 1.2, 3 ≤ γ ≤ 6.5, 0 ≤ ζ ≤ 0.5, 0 ≤ η ≤ 2.

[0055] As the compound represented by formula (A), the compounds represented by the following formulas (1) to (3) can be cited.

[0056] A α1 M β1 Z 6-δ1 X1 ε11 X2 ε12 (1)

[0057] A α2 M β2 X2 ε21 Z 6-γ2 X1 ε22 (2)

[0058] A α3 M β3 X1 ε31 Z δ3 D ζ O η (3)

[0059] In formula (1), A, M, and Z are an alkali metal element, a trivalent metal element or a metalloid element, and a halogen element respectively. As specific examples, those mentioned above can be cited. M preferably contains In. X1 and X2 are a doping element X1 and a doping element X2 respectively. As specific examples, those mentioned above can be cited. It can be 2 ≤ α1 ≤ 3.5, and can be 2.5 ≤ α1 ≤ 3. It can be 0.5 ≤ β1 ≤ 1.1, and can be 0.5 ≤ β1 ≤ 1. It can be 0 ≤ δ1 ≤ 1, and can be 0 ≤ δ1 ≤ 0.5. It can be 0 ≤ ε11 ≤ 0.7, can be 0 < ε11 ≤ 0.5, and can be 0.01 ≤ ε11 ≤ 0.3. It can be 0 ≤ ε12 ≤ 0.7, can be 0 < ε11 ≤ 0.5, and can be 0.01 ≤ ε11 ≤ 0.3.

[0060] In formula (2), A, M, and Z are an alkali metal element, a tetravalent metal element or a metalloid element, and a halogen element, respectively. As specific examples, those described above can be cited. M preferably contains Zr. X1 and X2 are a doping element X1 and a doping element X2, respectively. As specific examples, those described above can be cited. It can be 1.6 ≤ α2 ≤ 2.5, it can be 1.8 ≤ α2 ≤ 2.4, it can be 2 ≤ α2 ≤ 2.3. It can be 0 < β2 ≤ 1.1, it can be 0.5 ≤ β2 ≤ 1, it can be 0.8 ≤ β2 ≤ 1. It can be 0 ≤ γ2 < 1, it can be 0.01 ≤ γ2 ≤ 0.8, it can be 0.02 ≤ γ2 ≤ 0.7, it can be 0.1 ≤ γ2 ≤ 0.6, it can be 0.2 ≤ γ2 ≤ 0.6. It can be 0 ≤ ε21 ≤ 0.7, it can be 0 < ε21 ≤ 0.5, it can be 0.01 ≤ ε21 ≤ 0.3. It can be 0 ≤ ε22 ≤ 0.8, it can be 0 < ε21 ≤ 0.6. When X2 is iodine, it can be 0.01 ≤ ε21 ≤ 0.3, it can be 0.015 ≤ ε21 ≤ 0.1.

[0061] In formula (3), A, M, and Z are an alkali metal element, a tetravalent metal element or a metalloid element, and a halogen element, respectively. As specific examples, those described above can be cited. M preferably contains Zr. X1 and D are a doping element X1 and a doping element X3, respectively. As specific examples, those described above can be cited. It can be 1.5 ≤ α ≤ 3, it can be 1.8 ≤ α3 ≤ 2.5, it can be 1.9 ≤ α3 ≤ 2.3, it can be 1.95 ≤ α3 ≤ 2.2. It can be 0.5 ≤ β3 ≤ 2, it can be 0.7 ≤ β3 ≤ 1.4, it can be 0.8 ≤ β3 ≤ 1.2, it can be 0.9 ≤ β3 ≤ 1.1. It can be 0.005 ≤ ζ ≤ 0.5, it can be 0.01 ≤ ζ ≤ 0.2, it can be 0.02 ≤ ζ ≤ 0.15, it can be 0.025 ≤ ζ ≤ 0.10. It can be 3.5 ≤ δ3 ≤ 5, it can be 3.7 ≤ δ3 ≤ 4.3, it can be 3.8 ≤ δ3 ≤ 4.1. It can be 0.1 ≤ η ≤ 1.5, it can be 0.7 ≤ η ≤ 1.5, it can be 0.8 ≤ η ≤ 1.3, it can be 0.9 ≤ η ≤ 1.1.

[0062] The first solid electrolyte material can be in a particle shape. In this case, the average particle size of the first solid electrolyte material can be 1 to 50 μm. In addition, the particles of the first solid electrolyte material can have an uneven structure with a size of 0.5 to 2 μm. Microcracks with a size of 0.5 μm or more may not exist in the particles of the first solid electrolyte material.

[0063] The manufacturing method of the first solid electrolyte material is not particularly limited. For example, a method including a process of ball-milling raw materials can be cited. Annealing can be performed on the product after ball-milling. In addition, when obtaining a hexagonal solid electrolyte material, the manufacturing method of the first solid electrolyte material can be a method including a process of heating raw materials under a pressure of 1 GPa or more.

[0064] The raw materials are not particularly limited. For example, they can be alkali metal halides, chlorides of metal elements or metalloid elements other than alkali metals, and compounds containing doping elements X1 or X2. When the doping element is X1, the compound containing the doping element can be a halide of X1. When the doping element is X2, the compound containing the doping element can be an alkali metal bromide or an alkali metal iodide. The raw materials are preferably mixed before ball-milling, and more preferably mixed in an inert atmosphere (such as an Ar atmosphere).

[0065] The conditions for ball-milling are not particularly limited, but can be set to a rotation speed of 200 to 700 rpm for 10 to 100 hours. The pulverization time is preferably 24 hours to 72 hours, and more preferably 36 to 60 hours.

[0066] The balls used in ball-milling are not particularly limited, but zirconia balls can be used. The size of the balls used is not particularly limited, but balls of 2 mm to 10 mm can be used.

[0067] By ball-milling for the above-mentioned time, the raw materials are sufficiently mixed, and the mechanochemical reaction is promoted, thereby enabling the improvement of the ionic conductivity of the obtained compound.

[0068] Ball-milling can have multi-stage processes with different rotation speeds. For example, the process of ball-milling can sequentially have a first process, a second process, and a third process. The rotation speed of the second process can be greater than that of the first process and the third process. In addition, in this case, the rotation speed of the third process can be greater than that of the first process.

[0069] Annealing is preferably performed in an inert atmosphere or under vacuum. As the annealing temperature, for example, it is preferably 150 to 300 °C, and more preferably 200 to 250 °C. As the annealing time, for example, it can be 1 to 10 hours, and preferably 3 to 6 hours.

[0070] The negative electrode material of the present embodiment can be used as a composition for forming a negative electrode. The negative electrode material of the present embodiment can be used as a composition for forming a negative electrode of an electrochemical device such as a capacitor or a battery. As the battery, batteries that charge and discharge through the migration of alkali metal ions such as lithium ion batteries and sodium ion batteries can be cited. The battery can be a primary battery, a secondary battery, or an all-solid-state battery. The battery of the present embodiment includes a negative electrode, a positive electrode, and an electrolyte layer disposed between the negative electrode and the positive electrode. The negative electrode can be formed on a current collector from the negative electrode material. The positive electrode can be formed on a current collector from the positive electrode material.

[0071] The negative electrode material can further contain a polymer electrolyte, a binder resin, a conductive additive, an organic solvent, an ionic liquid, etc. as needed.

[0072] The negative electrode material of the present embodiment can further contain a binder resin (adhesive), a conductive additive, etc. As the binder resin, there is no particular limitation, and fluororesins can be cited. As the fluororesin, a resin having a carbon chain as the main chain is preferred. The carbon chain can be formed by radical polymerization of an ethylenically unsaturated group. As the fluororesin, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyvinylidene fluoride (PVDF), etc. can be cited. The content of the binder resin in the negative electrode material can be 0.5 to 10% by mass, or can be 1 to 7% by mass.

[0073] As the conductive additive, carbon materials such as natural graphite (scaly graphite, etc.), artificial graphite, etc.; carbon blacks such as acetylene black, Ketjen black, channel black, furnace black, lamp black, pyrolytic carbon black, etc.; carbon fibers; etc. can be cited. The content of the conductive additive in the electrode material can be 0.5 to 10% by mass, or can be 1 to 7% by mass.

[0074] The solid electrolyte material can contain a solid electrolyte material other than the first solid electrolyte material (hereinafter, also referred to as the second solid electrolyte material).

[0075] As the second solid electrolyte material, there is no particular limitation, and it can be an oxide (oxide-based solid electrolyte), a sulfide (sulfide-based solid electrolyte), a hydride (hydride-based solid electrolyte), etc. The second solid electrolyte material can contain an alkali metal element.

[0076] (Oxide-based solid electrolyte)

[0077] As the oxide-based solid electrolyte, for example, perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, garnet-type oxides, etc., and oxides doped with other cations or anions in the oxide can be cited.

[0078] As perovskite-type oxides, Li can be cited a La 1-a TiO 3 (0 < a < 1) and other Li-La-Ti-based oxides, Li b La 1-b TaO 3 (0 < b < 1) and other Li-La-Ta-based oxides, Li c La 1-c NbO 3 (0 < c < 1) and other Li-La-Nb-based oxides, etc.

[0079] As NASICON-type oxides, Li can be cited 1+d Al d Ti 2-d (PO 4 ) 3 (0 ≤ d ≤ 1), etc. NASICON-type oxides are Li m M 1 n M 2 o P p O q (In the formula, M 1 is one or more elements selected from B, Al, Ga, In, C, Si, Ge, Sn, Sb, and Se. M 2 is one or more elements selected from Ti, Zr, Ge, In, Ga, Sn, and Al. m, n, o, p, and q are arbitrary positive numbers.) The oxides represented can include Li 1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 (0 < x < 2, 0 < y < 3) (LATP), etc.

[0080] As LISICON-type oxides, Li can be cited 4 M 3 O 4 -Li 3 M 4 O 4 (M 3 is one or more elements selected from Si, Ge, and Ti. M 4 is one or more elements selected from P, As, and V.) The oxides represented, etc.

[0081] As garnet-type oxides, Li can be cited 7 La 3 Zr 2 O12 (LLZ), Li 7-a2 La 3 Zr 2-a2 Ta a2 O 12 (LLZT, where 0 < a2 < 1, or 0.1 < a2 < 0.8, or 0.2 < a2 < 0.6) and other Li-La-Zr based oxides, etc.

[0082] The oxide-based solid electrolyte can be a crystalline material or an amorphous material.

[0083] Examples of the oxide-based solid electrolyte include Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 、Li 0.33 La 0.55 TiO 3 etc.

[0084] (Sulfide-based solid electrolyte)

[0085] Examples of the sulfide-based solid electrolyte include Li 2 S-P 2 S 5 -based compounds, Li 2 S-SiS 2 -based compounds, Li 2 S-GeS 2 -based compounds, Li 2 S-B 2 S 3 -based compounds, Li 2 S-P 2 S 3 -based compounds, LiI-Si 2 S-P 2 S 5 、LiI-Li 2 S-P 2 O 5 、LiI-Li 3 PO 4 -P 2 S 5 、Li 10 GeP 2 S 12 etc.

[0086] It should be noted that in this specification, the expression "based compound" referring to the sulfide-based solid electrolyte mainly includes "Li 2 S", "P 2 S5 are used as a general term for solid electrolytes of raw materials such as. For example, for Li 2 S-P 2 S 5 system compounds, which contain Li 2 S and P 2 S 5 , and also contain solid electrolytes of other raw materials. In addition, Li 2 S-P 2 S 5 system compounds also include solid electrolytes with different mixing ratios of Li 2 S and P 2 S 5 .

[0087] As Li 2 S-P 2 S 5 system compounds, examples include Li 2 S-P 2 S 5 , Li 2 S-P 2 S 5 -LiI, Li 2 S-P 2 S 5 -LiCl, Li 2 S-P 2 S 5 -LiBr, 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 -Z m S n (m, n are positive numbers. Z is Ge, Zn or Ga), etc.

[0088] As Li 2 S-SiS 2 system compounds, examples include Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li 2 SO 4 , Li 2 S-SiS 2 -Li x MO y (x and y are positive numbers. M is P, Si, Ge, B, Al, Ga, or In, etc.)

[0089] As Li 2 S-GeS 2 series compounds, Li 2 S-GeS 2 , Li 2 S-GeS 2 -P 2 S 5 etc.

[0090] The sulfide-based solid electrolyte can be a crystalline material or an amorphous material.

[0091] (Hydride-based solid electrolyte)

[0092] As hydride-based solid electrolyte materials, LiBH 4 , LiBH 4 -3KI, LiBH 4 -PI 2 , LiBH 4 -P 2 S 5 , LiBH 4 -LiNH 2 , 3LiBH 4 -LiI, LiNH 2 , Li 2 AlH 6 , Li(NH 2 ) 2 , Li 2 NH, LiGd(BH 4 ) 3 , Li 2 (BH4 )(NH 2 )、Li 3 (NH 2 )I、Li 4 (BH 4 )(NH 2 ) 3 etc.

[0093] As the second solid electrolyte material, compounds obtained by replacing part or all of Li in the compounds exemplified as specific examples of oxide-based solid electrolytes, sulfide-based solid electrolytes, or hydride-based solid electrolytes with Na, K, Rb, or Cs can also be cited.

[0094] The electrolyte layer can be formed from an electrolyte composition. The electrolyte composition can contain a solid electrolyte material and, if necessary, a polymer electrolyte, a binder resin, an organic solvent, an ionic liquid, etc. The solid electrolyte material can contain at least one of the above-mentioned first solid electrolyte material and second solid electrolyte material.

[0095] The positive electrode material contains a positive electrode active material and, if necessary, can contain a solid electrolyte material, a polymer electrolyte, a binder resin, a conductive aid, an organic solvent, an ionic liquid, etc.

[0096] The positive electrode active material is not particularly limited. For example, alkali metal composite oxides containing an alkali metal element and a transition metal element can be cited. The transition metal element can be at least one selected from V, Cr, Mn, Fe, Co, Ni, Cu, Al, and can contain Ni. For example, when the alkali metal element is lithium (i.e., in the case of a lithium composite oxide), as the lithium-containing composite oxide, for example, LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiNi 0.5 Mn 1.5 O 4 , Li 2 MnO 3 , LiNi x Mn y Co 1-x- y O 2 [0 < x + y < 1]), LiNi x Co y Al 1-x-y O 2 [0 < x + y < 1]), LiCr 0.5 Mn 0.5 O 2 , LiFePO 4 , Li2 FeP 2 O 7 、LiMnPO 4 、LiFeBO 3 、Li 3 V 2 (PO 4 ) 3 、Li 2 CuO 2 、Li 2 FeSiO 4 、Li 2 MnSiO 4 etc. When the positive electrode active material contains an alkali metal element other than Li, as a specific example, an example in which Li in the above specific example is replaced with another alkali metal can be cited. As the alkali metal other than Li, Na or K can be cited.

[0097] The manufacturing method of the battery of the present embodiment is not particularly limited, and it can be a manufacturing method having a process of manufacturing a negative electrode by pressing a negative electrode material. This manufacturing method can further include a process of manufacturing an electrolyte layer by pressing an electrolyte composition. The process of manufacturing a negative electrode by pressing a negative electrode material and the process of manufacturing an electrolyte layer by pressing an electrolyte composition can be carried out simultaneously. In this case, the electrolyte composition is disposed on the negative electrode material, and they are pressed together to manufacture the negative electrode and the electrolyte layer. In addition, the positive electrode can be formed by disposing a positive electrode on the electrolyte layer or disposing a positive electrode material and pressing it.

[0098] Examples

[0099] (Example 1)

[0100] As the negative electrode active material, carbon-coated Li 4 Ti 5 O 12 (hereinafter also referred to as LTO) is used.

[0101] <Fabrication of Solid Electrolyte Material>

[0102] (Example 1)

[0103] In an argon atmosphere having a dew point of -70°C or lower (hereinafter referred to as a dry argon atmosphere), LiCl, ZrCl 4 and LiBr are weighed at a molar ratio of 1.5:1:0.5 to prepare raw materials.

[0104] In a zirconia container for planetary ball milling, the above raw materials were added, and 65 g of zirconia balls with a diameter of 4 mm were put in. Using a planetary ball milling device (manufactured by Verder Scientific Co., Ltd., PM 400), the mechanical chemical reaction was carried out under the conditions of 48 hours and 380 rpm, and thus a solid electrolyte material (Li 2 ZrCl 5.5 Br 0.5 ) was obtained. The ball milling was carried out in a mode where it stopped for 1 minute every 10 minutes of rotation and the rotation direction was alternately switched between clockwise and counterclockwise.

[0105] <Fabrication of secondary battery>

[0106] In a dry argon atmosphere, 37 parts by mass of the above solid electrolyte material, 60 parts by mass of LTO, and 3 parts by mass of acetylene black were weighed and mixed with a mortar, and thus a mixture was obtained.

[0107] In an insulating cylinder with an inner diameter of 10 mm, 100 mg of the above solid electrolyte material and 15 mg of the above mixture were sequentially laminated to obtain a laminate. A pressure of 370 MPa was applied to the laminate to form a first electrode (layer of the above mixture) and a first solid electrolyte layer (layer of the solid electrolyte material of Example 1).

[0108] Next, 60 mg of the sulfide solid electrolyte Li 6 PS 5 Cl was placed in contact with the first solid electrolyte layer to obtain a laminate. A pressure of 370 MPa was applied to the laminate to form a second solid electrolyte layer. The first solid electrolyte layer was clamped between the first electrode and the second solid electrolyte layer.

[0109] Next, 60 mg of In foil was placed in contact with the second solid electrolyte layer, and further 2 mg of Li foil was placed in contact with the In foil to obtain a laminate. A pressure of 370 MPa was applied to the laminate to form a second electrode.

[0110] A current collector made of stainless steel was installed on the first electrode and the second electrode, and then a lead wire was installed on the current collector. All components were arranged in a dryer and sealed. Thus, the secondary battery of Example 1 was obtained.

[0111] (Example 2)

[0112] <Fabrication of solid electrolyte material>

[0113] In an argon atmosphere with a dew point of -70 °C or lower (hereinafter, referred to as a dry argon atmosphere), 0.4257 g of LiCl and 0.7044 g of InCl 3, 0.0784 g of ZrCl 4 , prepare the raw materials.

[0114] Add the above raw materials to the zirconia container for planetary ball milling, and put in 65 g of zirconia balls with a diameter of 4 mm. Treat them in such a way that a mechanical chemical reaction is carried out under the conditions of 48 hours and 380 rpm, thereby obtaining the crude composition of Example 2.

[0115] Planetary ball milling device: PM 400 manufactured by Verder Scientific Co., Ltd.

[0116] · Annealing

[0117] For the crude composition of Example 2 obtained above, heat it at 230 °C for 5 hours in an argon atmosphere, thereby obtaining a compound (lithium-containing chloride) with a feed composition of Li 2.89 In 0.91 Zr 0.096 Cl 6 .

[0118] <Fabrication of secondary battery>

[0119] Except for using 50 parts by mass of the solid electrolyte material of Example 2 and 50 parts by mass of LTO to form the first electrode, fabricate the secondary battery of Example 2 in the same manner as in Example 1.

[0120] (Example 3)

[0121] <Fabrication of secondary battery>

[0122] In a dry argon atmosphere, weigh 50 parts by mass of the solid electrolyte material of Example 2 and 50 parts by mass of LTO, and mix them in a mortar to obtain a negative electrode material mixture.

[0123] In addition, weigh 29 parts by mass of the solid electrolyte material of Example 2, 67 parts by mass of LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 3 , and 4 parts by mass of acetylene black, and mix them in a mortar to obtain a positive electrode material mixture.

[0124] In an insulating cylinder with an inner diameter of 10 mm, stack 200 mg of the solid electrolyte material of Example 2 and 15 mg of the above positive electrode material mixture in sequence to obtain a stacked body. Apply a pressure of 370 MPa to the stacked body to form the first electrode (layer of the above mixture) and the solid electrolyte layer.

[0125] Next, 25 mg of the above-described negative electrode material mixture was added in contact with the solid electrolyte layer to obtain a laminate. A pressure of 370 MPa was applied to the laminate to form the second electrode.

[0126] A current collector made of stainless steel was attached to the first electrode and the second electrode. Next, leads were attached to the current collector. All components were placed in a dryer and sealed. Thus, the secondary battery of Example 3 was obtained.

[0127] (Example 4)

[0128] (Production of Solid Electrolyte Material)

[0129] ·Ball Milling

[0130] In an argon atmosphere having a dew point of -70°C or lower (hereinafter, referred to as a dry argon atmosphere), a total of 1.2 g of Li 2 Zr 0.95 Mg 0.05 Cl 3.9 O(PO 4 ) 0.033 was weighed in a composition such that 2 O, ZrCl 4 , MgCl 2 , Li 3 PO 4 , and raw materials were prepared.

[0131] The above raw materials were placed in a 50 ml zirconia container for a planetary ball mill, and 65 g of zirconia balls with a diameter of 4 mm were added. The treatment was carried out under the condition of a mechanical chemical reaction at 300 rpm for 24 hours, thereby obtaining the solid electrolyte material of Example 4.

[0132] The ball milling was carried out at intervals of stopping for 1 minute every 10 minutes of rotation, and the rotation direction was alternately switched between clockwise and counterclockwise. The feed composition of the obtained solid electrolyte material was Li 2.15 ZrCl 4 O(PO 4 ) 0.05 .

[0133] Planetary Ball Mill: PM 400 manufactured by Verder Scientific Co., Ltd.

[0134] (Production of Secondary Battery)

[0135] In a dry argon atmosphere, 50 parts by mass of the solid electrolyte material of Example 4 and 50 parts by mass of LTO were weighed and mixed in a mortar to obtain a negative electrode material mixture. Except for this, a secondary battery of Example 4 was fabricated in the same manner as in Example 1.

[0136] (Example 5)

[0137] <Fabrication of Secondary Battery>

[0138] Using the solid electrolyte material of Example 4 instead of the solid electrolyte material of Example 2, a secondary battery of Example 5 was fabricated in the same steps as in Example 3 except for this.

[0139] <Charge and Discharge Tests>

[0140] As the charge and discharge testing machine, the following product was used for implementation.

[0141] Charge and Discharge Testing Machine: Toyo System Co., Ltd. TOSCAT-3100

[0142] At 60 °C, charge and discharge tests were performed on the above secondary battery at two C-rates of 0.05C (first cycle and second cycle) and 0.1C (third cycle and fourth cycle).

[0143] With constant current (CC charging, CC discharging), discharge was carried out to 0.8V at a current density corresponding to each C-rate. Regarding charging, discharge was carried out to 1.3V at a current density corresponding to each C-rate. Regarding discharge, it was carried out under the condition of ending at 140 mAh / g per capacity of LTO.

[0144] Figure 1 The results of the charge and discharge tests of the secondary battery of Example 1 (first cycle and second cycle) are shown. Figure 2 The results of the charge and discharge tests of the secondary battery of Example 1 (third cycle and fourth cycle) are shown. Charge and discharge were confirmed in any cycle, and a discharge capacity of 140 mAh / g could be observed.

[0145] It should be noted that in the above charge and discharge tests, since the potential of LTO is higher than that of Li-In, although it is set to have an electrode containing LTO as the positive electrode, it has been shown that a battery with an electrode containing LTO works well and it can be known that it can also be used as the negative electrode.

[0146] <Charge and Discharge Tests of the Secondary Battery of Example 2>

[0147] Using the above charge and discharge testing machine, charge and discharge tests were performed on the secondary battery of Example 2 at three rates of 0.1C, 0.5C, and 1C at 60 °C.

[0148] Discharge at a constant current (CC charging, CC discharging) to 0.85 V at a current density corresponding to the respective C-rates. For charging, charge to 1.3 V at a current density corresponding to the respective C-rates.

[0149] Figure 3 Shows the results of the charge-discharge tests of the secondary battery of Example 2.

[0150] Note that in the above charge-discharge tests, the potential of LTO is higher than that of Li-In. Therefore, although it is set up with an electrode containing LTO as the positive electrode, it has been shown that a battery with an electrode containing LTO operates well and can be used as the negative electrode.

[0151] <Charge-Discharge Tests of the Secondary Battery of Example 3>

[0152] Using the above charge-discharge testing machine, charge-discharge tests were performed on the secondary battery of Example 3 at 60 °C at four rates of 0.05 C, 0.1 C, 0.5 C, and 1 C. The current densities corresponding to the respective rates are shown in Table 1.

[0153] Table 1

[0154] C rate <![CDATA[Current density (mA / cm 2 )]]> 0.1C 0.19 1C 1.9 3C 5.8

[0155] Charge at a constant current and constant voltage (CCCV charging) to 2.75 V at a current density corresponding to the respective C-rates.

[0156] For discharging, discharge to 0.95 V at a current density corresponding to the respective C-rates.

[0157] Figure 4 Shows the results of the charge-discharge tests of the secondary battery of Example 3.

[0158] <Charge-Discharge Tests of the Secondary Battery of Example 4>

[0159] Using the above charge-discharge testing machine, charge-discharge tests were performed on the secondary battery of Example 4 at 60 °C at two rates of 0.1 C and 0.5 C.

[0160] Discharge at a constant current (CCCV charging, CC discharging) to 0.85 V at a current density corresponding to the respective C-rates. For charging, charge to 1.3 V at a current density corresponding to the respective C-rates.

[0161] Figure 5 Shows the results of the charge-discharge tests of the secondary battery of Example 4.

[0162] It should be noted that in the above charge-discharge test, the potential of LTO is higher than that of Li-In. Therefore, although it is set up with an electrode containing LTO as the positive electrode, it has been shown that a battery with an electrode containing LTO works well, indicating that it can also be used as the negative electrode.

[0163] <Charge-Discharge Test of the Secondary Battery of Example 5>

[0164] Using the above charge-discharge testing machine, the secondary battery of Example 3 was subjected to charge-discharge tests at four rates of 0.05C, 0.1C, 0.5C, and 1C at 25°C.

[0165] With constant current and constant voltage (CCCV charging), charging was carried out to 2.75V at a current density corresponding to each C rate. The current densities corresponding to each C rate are shown in Table 1 above.

[0166] For discharging, discharging was carried out to 0.95V at a current density corresponding to each C rate.

[0167] Figure 6 Shows the results of the charge-discharge test of the secondary battery of Example 5.

[0168] (Comparative Example 1)

[0169] Loaded LiCl and YCl as raw materials in a composition ratio of Li 3 YCl 6 A total of 4 g was charged, 65 g of zirconia balls were added, and ball milling was carried out under the conditions of 300 rpm for 24 hours. Except for this, Li 3 was obtained under the same conditions as in Example 1. 3 YCl 6 .

[0170] Using Li 3 YCl 6 to replace the solid electrolyte material of Example 1, and except for this, the charge-discharge test was carried out under the same conditions, but charge-discharge could not be carried out.

Claims

1. A negative electrode material, which comprises a negative electrode active material and a solid electrolyte material, The solid electrolyte material contains an alkali metal element, a metal element or a metalloid element other than the alkali metal element, and a halogen element, The metal element or metalloid element other than the alkali metal contains at least one of Zr and In.

2. The negative electrode material according to claim 1, wherein, In the solid electrolyte material, the total amount of Zr and In is more than the total amount of the alkali metal element, the metal element or metalloid element other than Zr and In.

3. The negative electrode material according to claim 1 or 2, wherein, In the solid electrolyte material, the content of Y in terms of the amount of substance is less than the total amount of Zr and In.

4. The negative electrode material according to claim 1 or 2, wherein, The solid electrolyte material contains A α M β Z γ D ζ O η denoted compound In the formula, A is an alkali metal element, M is at least one of Zr and In, Z is a halogen element, D is at least one of P and S, 1.6 ≤ α ≤ 3.5, 0 < β ≤ 1.2, 3 ≤ γ ≤ 6.5, 0 ≤ ζ ≤ 0.5, 0 ≤ η ≤ 2.

5. The negative electrode material according to claim 1 or 2, wherein, The volume ratio of the negative electrode active material to the total volume of the negative electrode active material and the solid electrolyte material is 0.30 to 0.

90.

6. The negative electrode material according to claim 1 or 2, wherein, The negative electrode active material is an oxide containing titanium.

7. The negative electrode material according to claim 1 or 2, which further comprises an ionic liquid.

8. A negative electrode, which comprises the negative electrode material according to claim 1 or 2.

9. A battery, which comprises the negative electrode according to claim 8.

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