Battery and laminate

Abstract

A battery provided with a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode, the electrolyte layer including a first electrolyte layer and a second electrolyte layer, the first electrolyte layer being disposed between the positive electrode and the second electrolyte layer, the first electrolyte layer containing a material different from that of the second electrolyte layer, and the second electrolyte layer containing a material different from that of the first electrolyte layer. The first electrolyte layer contains a solid electrolyte material that contains an alkali metal element, a metal element or semimetal element other than the alkali metal element, and a halogen element, and the metal element or semimetal element other than the alkali metal element contains Zr and / or In.

Description

Technical Field

[0001] The present disclosure relates to a battery and a laminate. Background Art

[0002] Lithium-ion batteries and other batteries that are charged and discharged with the movement of metal ions between the positive electrode and the negative electrode are actively studied because they have high capacity. As electrolytes for lithium-ion batteries, solutions of lithium salts containing organic solvents or ionic liquids are known, but solid electrolytes are studied from the perspective of safety and processability. As solid electrolytes, various types of compounds such as oxide-based solid electrolytes and sulfide-based solid electrolytes are known.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2019 / 135323

[0006] Patent Document 2: International Publication No. 2021 / 002064 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, conventional batteries having solid electrolytes cannot sufficiently reduce resistance, and microcracks and the like are easily generated in the electrolyte layer.

[0009] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a battery and a laminate in which microcracks are less likely to occur in a layer including an electrolyte layer.

[0010] Means for solving problems

[0011] The present disclosure includes the following embodiments [1] to [8].

[0012] [1] A battery,

[0013] It comprises a positive electrode, a negative electrode and an electrolyte layer disposed between the positive electrode and the negative electrode.

[0014] The electrolyte layer includes a first electrolyte layer and a second electrolyte layer.

[0015] The first electrolyte layer is disposed between the positive electrode and the second electrolyte layer.

[0016] The first electrolyte layer includes a material different from that of the second electrolyte layer.

[0017] The first electrolyte layer comprises a solid electrolyte material containing an alkali metal element, a metal element or a semi-metal element other than an alkali metal element, and a halogen element.

[0018] The metal element or semi-metal element other than the alkali metal element includes at least one of Zr and In.

[0019] [2] The battery according to [1], wherein:

[0020] The solid electrolyte material comprises A α M β Z γ D ζ O η The compounds represented by

[0021] In the formula, A is an alkali metal element, M is a metal element or a semi-metal 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.

[0022] [3] The battery according to [1] or [2], wherein:

[0023] The second electrolyte layer includes an oxide solid electrolyte.

[0024] [4] The battery according to any one of [1] to [3], wherein

[0025] The thickness ratio of the first electrolyte layer to the second electrolyte layer is 1:0.2 to 1:1.

[0026] [5] The battery according to any one of [1] to [4], wherein

[0027] The first electrolyte layer further contains an ionic liquid.

[0028] [6] The battery according to any one of [1] to [5], wherein

[0029] In the Nyquist curve obtained by measuring the impedance in the range of 0.1 Hz to 891 kHz by clamping the stack composed of the above-mentioned positive electrode and the above-mentioned first electrolyte layer between two SUS plates, the frequency at which the phase angle becomes minimum is 100 kHz to 891 kHz, and the ratio A / B of the real part resistance value (A) of the impedance measurement at the frequency where the phase angle becomes minimum to the real part resistance value (B) of the impedance at 891 kHz is 1.0 to 3.5.

[0030] [7] A laminated body,

[0031] It comprises a positive electrode and an electrolyte layer disposed on the positive electrode.

[0032] The electrolyte layer includes a first electrolyte layer and a second electrolyte layer.

[0033] The first electrolyte layer is disposed between the positive electrode and the second electrolyte layer.

[0034] The first electrolyte layer includes a material different from that of the second electrolyte layer.

[0035] The first electrolyte layer comprises a solid electrolyte material containing an alkali metal element, a metal element or a semi-metal element other than an alkali metal element, and a halogen element.

[0036] The metal element or semi-metal element other than the alkali metal element includes at least one of Zr and In.

[0037] [8] The laminate according to [7], wherein

[0038] In the Nyquist curve obtained by measuring the impedance in the range of 0.1 Hz to 891 kHz by clamping the stack composed of the above-mentioned positive electrode and the above-mentioned first electrolyte layer between two SUS plates, the frequency at which the phase angle becomes minimum is 100 kHz to 891 kHz, and the ratio A / B of the real part resistance value (A) of the impedance measurement at the frequency where the phase angle becomes minimum to the real part resistance value (B) of the impedance at 891 kHz is 1.0 to 3.5.

[0039] Effects of the Invention

[0040] According to the present disclosure, it is possible to provide a battery and a laminated body in which microcracks are less likely to occur in a layer including an electrolyte layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a graph showing the results of the charge and discharge test of the secondary battery of Example 1.

[0042] Figure 2 This is a graph showing the results of a charge and discharge test of the secondary battery of Example 2.

[0043] Figure 3 This is a scanning electron microscope image of the solid electrolyte material of Example 3.

[0044] Figure 4 Yes Figure 3 A diagram obtained by enlarging a portion of .

[0045] Figure 5 This is a scanning electron microscope image of a cross section of the laminate of Example 3.

[0046] Figure 6 This is a scanning electron microscope image of the solid electrolyte material of Comparative Example 1.

[0047] Figure 7 Yes Figure 6 A diagram obtained by enlarging a portion of .

[0048] Figure 8 This is a scanning electron microscope image of a cross section of the laminate of Comparative Example 1.

[0049] Fig. 9 It is the Nyquist curve of the laminated body of Example 3 and Comparative Example 1. DETAILED DESCRIPTION

[0050] The battery of this embodiment includes a positive electrode (which may be a positive electrode layer), a negative electrode (which may be a negative electrode layer), and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the electrolyte layer includes a first electrolyte layer and a second electrolyte layer, wherein the first electrolyte layer is disposed between the positive electrode and the second electrolyte layer, wherein the first electrolyte layer includes a material different from that of the second electrolyte layer, and wherein the first electrolyte layer includes a solid electrolyte material containing an alkali metal element, a metal element or a semimetal element other than an alkali metal element, and a halogen element. The metal element or the semimetal element other than an alkali metal element may include at least one of Zr and In.

[0051] In the Nyquist curve obtained by measuring the impedance in the range of 0.1 Hz to 891 kHz by clamping the stack consisting of the positive electrode and the first electrolyte layer between two SUS plates, the frequency at which the phase angle becomes minimum is 100 kHz to 891 kHz, and the ratio A / B of the resistance value (A) of the impedance measurement to the resistance value (B) of the real part of the impedance at 891 kHz can be 1.0 to 3.5.

[0052] The ratio A / B may be 1.0 to 3.0, or 1.0 to 2.8. In addition, the frequency at which the phase angle becomes minimum may be 200 kHz or more, or 220 kHz or more.

[0053] The electrolyte layer includes a solid electrolyte material (halide-based solid electrolyte) containing an alkali metal element, a metal element or a semi-metal element other than an alkali metal element, and a halogen element. Hereinafter, the solid electrolyte material containing an alkali metal element, a metal element or a semi-metal element other than an alkali metal element, and a halogen element is also referred to as the first solid electrolyte material. The first solid electrolyte material may be a material that satisfies 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.

[0054] The alkali metal element contained in the first solid electrolyte material may be any one of Li, Na, K, Rb and Cs, but may include at least one of Li, Na and K, may include at least one of Li and Na, and may include Li.

[0055] Among the alkali metal elements contained in the first solid electrolyte material, the ratio of one alkali metal element may be 80 mol % or more, 90 mol % or more, or 95 mol % or more. The one alkali metal element may be at least one of Li, Na, and K, at least one of Li and Na, or Li.

[0056] The content of the alkali metal element in the first solid electrolyte material may be 15 to 30 mol %, 18 to 28 mol %, or 20 to 27 mol % relative to the total amount of atoms contained in the first solid electrolyte material.

[0057] The metal element or semimetal element other than the alkali metal element is not particularly limited, but divalent to pentavalent elements can be listed, and one or more selected from the group consisting of trivalent elements and tetravalent elements can be included. The first solid electrolyte material can include one or two or more metal elements or semimetal elements other than the alkali metal element.

[0058] As divalent elements, alkaline earth metals, Zn, etc. can be listed. As alkaline earth metals, it can be at least one of Mg, Ca, Sr and Ba, it can be at least one of Mg and Ca, or it can be Mg. As trivalent metal elements, Sc, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu, Y, Al, Ga, In, Bi, Sb, etc. can be listed. As tetravalent elements, Zr, Ti, Hf, Sn, etc. can be listed, and it can be Zr. As pentavalent metal elements, Nb, Ta, etc. can be listed. As hexavalent or higher elements, W can be listed.

[0059] The metal element or semi-metal element other than the alkali metal element may include at least one of In and Zr. The content of the metal element or semi-metal 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 elements contained in the first solid electrolyte material.

[0060] In the first solid electrolyte material, the total mass of Zr and In may be greater than the total mass of the alkali metal element, the metal element or the semi-metal element other than Zr and In. It should be noted that, in the case where the first solid electrolyte material contains only one of Zr and In, the total mass is the content of the contained element. The total mass of Zr and In in the first solid electrolyte material may be 60 mol% or more of the total mass of the metal element or the semi-metal element other than the alkali metal element, may be 70 mol% or more, may be 80 mol% or more, may be 90 mol% or more.

[0061] In the first solid electrolyte material, the content of Y by mass may also be less than the total mass of Zr and In. It should be noted that, in the case where the first solid electrolyte material contains only one of Zr and In, the total mass is the content of the contained elements. The content of Y in the first solid electrolyte may be 40 mol% or less, 30 mol% or less, 20 mol% or less, or 10 mol% or less relative to the total mass of metal elements or semi-metal elements other than alkali metal elements. The first solid electrolyte material may also be substantially free of Y.

[0062] The first solid electrolyte material may contain 70 mol% or more of one element of the metal elements or semi-metal elements other than alkali metal elements relative to the total amount of the metal elements or semi-metal elements other than alkali metal elements, may contain 75 mol% or more, may contain 80 mol% or more. In this case, as the one element, it may be a trivalent or tetravalent element, and may be In or Zr. In this case, the first solid electrolyte material contains metal elements or semi-metal elements other than alkali metal elements other than the one element (also referred to as doping element X1). The doping element X1 is an element different from the above one element. In the case where the above one element is a trivalent element, the doping element X1 may be at least one element selected from the group consisting of Zr, Sn, Ti, Nb, Ta, Bi and Y, and may be at least one element selected from the group consisting of Zr, Sn, Nb and Ta. When the above-mentioned one element is a tetravalent element, the doping element X1 may be at least one element selected from the group consisting of Bi, Al, Ga, In, Sc, Sm, Sb, La, Zn, Sn and alkaline earth metals, and may be at least one element selected from the group consisting of Bi, La, Zn and Sn. As the hexavalent or higher element, W may be listed.

[0063] The halogen element contained in the first solid electrolyte material of the present embodiment may be any one of F, Cl, Br and I, but may include at least one of Cl, Br and I, may include at least one of Cl and Br, and may include Cl. The ion conductive material may also include only one halogen element, but may also include two or more halogen elements. In the case where the first solid electrolyte material includes Zr as a metal element other than an alkali metal element, the first solid electrolyte material may include two or more halogen elements, may include Cl and a halogen element other than Cl, and may include Cl and Br. The content of the halogen element other than Cl or Br may be less than 10 mol%, may be 0.1 to 10 mol%, and may be 1 to 8 mol% relative to the total amount of the halogen elements contained in the first solid electrolyte material.

[0064] 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 elements contained in the halogen element.

[0065] The first solid electrolyte material may contain 80 mol % or more of one element of the halogen elements relative to the total amount of the halogen elements, may contain 85 mol % or more, and may contain 90 mol % or more. The one halogen element may be Cl or Br, and may be Cl. In this case, the first solid electrolyte material contains halogen elements other than the one halogen element (also referred to as doping element X2). When the one halogen element is Cl, the doping element X2 may be at least one of Br and I, and may be Br.

[0066] The first solid electrolyte material may contain at least one of P and S (also referred to as doping element X3). The content of the doping element X3 in the first solid electrolyte material may be 0.05 to 5 mol %, 0.1 to 3 mol %, 0.2 to 2 mol %, or 0.3 to 1 mol % relative to the total amount of atoms contained in the first solid electrolyte material.

[0067] When the first solid electrolyte material includes at least one of P and S, the first solid electrolyte material may include a tetravalent metal element or a semi-metal element. Examples of the tetravalent metal element or semi-metal element include Zr, Ti, Hf, and the like, and Zr may be used. In addition, as the doping element X2, at least one of Hf and Mg may be included.

[0068] The content of the doping element X3 in the first solid electrolyte material may be 50 mol% or less of the content of the tetravalent metal element or semi-metal element, may be 1 to 30 mol%, may be 1 to 20 mol%, may be 2 to 10 mol%. The content of the doping element X in the first solid electrolyte material may be 20 mol% or less of the content of the tetravalent metal element or semi-metal element, may be 15 mol% or less, may be 10 mol% or less, may be 8 mol% or less.

[0069] The first solid electrolyte material may have a hexagonal crystal structure and may have a structure belonging to the space group P6. 3 The solid electrolyte material having a hexagonal crystal structure may include at least one element selected from the group consisting of Sc, La, Y, Ga, In, Bi, Sb, Ge, Zr, Sn, Nb and Ta, and may include Sc.

[0070] The first solid electrolyte material may include a compound represented by the following formula (A).

[0071] A α Mβ Z γ D ζ O η (A)

[0072] Among them, A is an alkali metal, M is a metal element or a semi-metal 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.

[0073] Examples of the compound represented by formula (A) include compounds represented by the following formulae (1) to (3).

[0074] A α1 M β1 Z 6-δ1 X1 ε11 X2 ε12 (1)

[0075] A α2 M β2 X2 ε21 Z 6-γ2 X1 ε22 (2)

[0076] A α3 M β3 X1 ε31 Z δ3 D ζ O η (3)

[0077] In formula (1), A, M and Z are alkali metal elements, trivalent metal elements or semimetal elements, halogen elements, and the above-mentioned elements can be listed as specific examples. M preferably contains In. X1 and X2 are doping elements X1 and X2, and the above-mentioned elements can be listed as specific examples. 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, and can be 0<ε11≤0.5, and can be 0.01≤ε11≤0.3. It can be 0≤ε12≤0.7, and can be 0<ε11≤0.5, and can be 0.01≤ε11≤0.3.

[0078] In formula (2), A, M and Z are alkali metal elements, tetravalent metal elements or semi-metal elements, halogen elements, and the above-mentioned elements can be listed as specific examples. M preferably contains Zr. X1 and X2 are doping elements X1 and X2, and the above-mentioned elements can be listed as specific examples. It can be 1.6≤α2≤2.5, 1.8≤α2≤2.4, or 2≤α2≤2.3. It can be 0<β2≤1.1, 0.5≤β2≤1, or 0.8≤β2≤1. It can be 0≤γ2<1, 0.01≤γ2≤0.8, 0.02≤γ2≤0.7, 0.1≤γ2≤0.6, or 0.2≤γ2≤0.6. It can be 0≤ε21≤0.7, 0<ε21≤0.5, or 0.01≤ε21≤0.3. It may be 0≤ε22≤0.8, or 0<ε21≤0.6. When X2 is iodine, it may be 0.01≤ε21≤0.3, or 0.015≤ε21≤0.1.

[0079] In formula (3), A, M and Z are alkali metal elements, tetravalent metal elements or semi-metal elements, halogen elements, and the above-mentioned elements can be listed as specific examples. M preferably contains Zr. X1 and D are doping elements X1 and X3, respectively, and the above-mentioned elements can be listed as specific examples. It can be 1.5≤α≤3, 1.8≤α3≤2.5, 1.9≤α3≤2.3, or 1.95≤α3≤2.2. It can be 0.5≤β≤2, 0.7≤β3≤1.4, 0.8≤β3≤1.2, or 0.9≤β3≤1.1. It can be 0.005≤ζ≤0.5, 0.01≤ζ≤0.2, 0.02≤ζ≤0.15, or 0.025≤ζ≤0.10. It can be 3.5≤δ3≤5, 3.7≤δ3≤4.3, or 3.8≤δ3≤4.1. It can be 0.1≤η≤1.5, 0.7≤η≤1.5, 0.8≤η≤1.3, or 0.9≤η≤1.1.

[0080] The first solid electrolyte material may be in the form of particles. In this case, the average particle size of the first solid electrolyte material may be 1 to 50 μm. In addition, the particles of the first solid electrolyte material may have a concave-convex structure of 0.5 to 2 μm in size. In the particles of the first solid electrolyte material, there may be no microcracks of a size of 0.5 μm or more.

[0081] The method for producing the first solid electrolyte material is not particularly limited, but for example, a method having a process of ball milling the raw material can be cited. The product after ball milling can also be annealed. In addition, in the case of obtaining a hexagonal solid electrolyte material, the method for producing the first solid electrolyte material can also be a method comprising a process of heating the raw material under a pressure of 1 GPa or more.

[0082] As a raw material, there is no particular limitation, for example, it can be a compound containing an alkali metal halide, a chloride of a metal element or a semi-metal element other than an alkali metal, and a doping element X1 or X2. In the case where the doping element is X1, the compound containing the doping element can be a halide of X1. In the case where 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 under an inert atmosphere (e.g., Ar atmosphere).

[0083] The ball milling conditions 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 to 72 hours, more preferably 36 to 60 hours.

[0084] The balls used for 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.

[0085] By performing ball milling for the above-mentioned time, the raw materials are sufficiently mixed, and the mechanochemical reaction is promoted, thereby improving the ion conductivity of the obtained compound.

[0086] The ball milling may have a multi-stage process with different rotation speeds. For example, the process of ball milling may have a first process, a second process, and a third process in sequence, and the second process may have a higher rotation speed than the first process and the third process. In addition, in this case, the third process may have a higher rotation speed than the first process.

[0087] Annealing is preferably performed in an inert atmosphere or in a vacuum. The annealing temperature is, for example, preferably 150 to 300° C., more preferably 200 to 250° C. The annealing time is, for example, 1 to 10 hours, preferably 3 to 6 hours.

[0088] The positive electrode active material is not particularly limited, and examples thereof include alkali metal composite oxides containing an alkali metal element and at least one metal element selected from the group consisting of transition metal elements and Al. The transition metal element may be at least one selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and Cu, and may include Ni. For example, when the alkali metal element is lithium (i.e., in the case of a lithium composite oxide), examples of the lithium composite oxide include 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 , Li 2 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 When the positive electrode active material contains an alkali metal element other than Li, specific examples thereof include those obtained by replacing the Li in the above specific examples with other alkali metals. Examples of alkali metals other than Li include Na and K.

[0089] The positive electrode (positive electrode material) of the present embodiment may further include a solid electrolyte material, a binding resin (binder), a conductive aid, and the like. As the binding resin, there is no particular limitation, but fluorine-based resins may be cited. As fluorine-based resins, resins having a carbon chain as a main chain are preferred. The carbon chain may be a carbon chain formed by free radical polymerization of ethylenically unsaturated groups. As fluororesins, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyvinylidene fluoride (PVDF), and the like may be cited. The content of the binding resin in the positive electrode may be 0.5 to 10% by mass, and may be 1 to 7% by mass.

[0090] As the conductive aid, graphites such as natural graphite (e.g., flaky graphite) and artificial graphite; carbon blacks such as acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black; carbon fibers; and other carbon materials can be listed. The content of the conductive aid in the positive electrode can be 0.5 to 10% by mass, and can be 1 to 7% by mass.

[0091] The solid electrolyte material contained in the positive electrode may be one or both of the first solid electrolyte material and the second solid electrolyte material described above.

[0092] The content of the positive electrode active material in the positive electrode material (or positive electrode) can be 50 mass % or more, 60 mass % or more, 70 mass % or more, 95 mass % or less, or 90 mass % or less relative to the total amount of the positive electrode material.

[0093] The negative electrode material may include a negative electrode active material and, if necessary, a polymer electrolyte, a binding resin, a conductive aid, an organic solvent, an ionic liquid, and the like.

[0094] As negative electrode active materials, there can be listed simple substances of alkali metal elements, Si, P, Sn, Si-Mn, Si-Co, Si-Ni, In, Au and the like, alloys or composites containing these elements, carbon materials such as graphite, substances obtained by inserting alkali metal ions between the layers of the carbon materials, oxides containing titanium, etc. The alkali metal element can be Li, Na or K, can be Li or Na, can be Li.

[0095] The oxide containing titanium may be a compound having the composition formula: s TiO t The compound given (A is an alkali metal element, s≥0). The alkali metal element A can be Li, Na or K, can be Li or Na, can be Li.

[0096] The first electrolyte layer may be a layer formed of a first electrolyte composition. The first electrolyte composition may include a solid electrolyte material and, as required, a polymer electrolyte, a binding resin, an organic solvent, an ionic liquid, etc. The solid electrolyte material may include at least one of the above-mentioned first solid electrolyte material and an optional solid electrolyte material other than the first solid electrolyte material (second solid electrolyte material).

[0097] The second solid electrolyte material is not particularly limited, and may be an oxide (oxide-based solid electrolyte), a sulfide (sulfide-based solid electrolyte), a hydride (hydride-based solid electrolyte), or the like. The second solid electrolyte material may contain an alkali metal element.

[0098] (Oxide-based solid electrolyte)

[0099] Examples of the oxide-based solid electrolyte include oxides such as perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, and garnet-type oxides, and oxides doped with other cations or anions.

[0100] Examples of perovskite-type oxides include Li a La 1-a TiO 3 (0 <a<1)等Li-La-Ti系氧化物、Li b La 1-b TaO 3 (0 <b<1)等Li-La-Ta系氧化物、Li c La 1-c NbO 3 (0 <c<1)等Li-La-Nb系氧化物等。

[0101] Examples of NASICON-type oxides include Li 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 (Where M 1 M is one or more elements selected from the group consisting of B, Al, Ga, In, C, Si, Ge, Sn, Sb and Se. 2is one or more elements selected from the group consisting of Ti, Zr, Ge, In, Ga, Sn and Al. m, n, o, p and q are any positive numbers. The oxide represented by ) includes Li 1+x+y Al x (Ti, Ge) 2-x Si y P 3-y O 12 (0 <x<2、0<y<3)(LATP)等。

[0102] Examples of LISICON type oxides include Li 4 M 3 O 4 -Li 3 M 4 O 4 (M 3 M is one or more elements selected from the group consisting of Si, Ge, and Ti. 4 It is one or more elements selected from the group consisting of P, As and V. ) Oxides represented by, etc.

[0103] Examples of garnet-type oxides include Li 7 La 3 Zr 2 O 12 (LLZ), Li 7-a2 La 3 Zr 2-a2 Ta a2 O 12 (LLZT, can be 0 <a2<1,可以为0.1<a2<0.8,0.2<a2<0.6)等Li-La-Zr系氧化物等。

[0104] The oxide-based solid electrolyte may be a crystalline material or an amorphous material.

[0105] Examples of oxide-based solid electrolytes include Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 , Li 0.33 La 0.55 TiO 3 wait.

[0106] (Sulfide-based solid electrolyte)

[0107] Examples of sulfide-based solid electrolytes include Li 2 SP 2 S 5 Compounds, Li 2S-SiS 2 Compounds, Li 2 S-GeS 2 Compounds, Li 2 SB 2 S 3 Compounds, Li 2 SP 2 S 3 System compounds, LiI-Si 2 SP 2 S 5 、LiI-Li 2 SP 2 O 5 、LiI-Li 3 PO 4 -P 2 S 5 , Li 10 G 2 S 12 wait.

[0108] In this specification, the expression "sulfide-based compound" which refers to a sulfide-based solid electrolyte mainly includes "Li 2 S" "P 2 S 5 " is used as a general term for solid electrolytes made of raw materials such as Li 2 SP 2 S 5 Series compounds, including Li 2 S and P 2 S 5 , a solid electrolyte further comprising other raw materials. In addition, for Li 2 SP 2 S 5 compounds, including Li 2 S and P 2 S 5 Solid electrolytes with different mixing ratios.

[0109] As Li 2 SP 2 S 5 System compounds, including Li 2 SP 2 S 5 , Li 2 SP 2 S 5 -LiI, Li 2 SP 2 S 5 -LiCl, Li 2 SP2 S 5 -LiBr, Li 2 SP 2 S 5 -Li 2 O. Li 2 SP 2 S 5 -Li 2 O-LiI、Li 2 SP 2 S 5 -Z m S n (m and n are positive numbers. Z is Ge, Zn or Ga), etc.

[0110] As Li 2 S-SiS 2 System compounds, including 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-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.

[0111] As Li 2 S-GeS 2 System compounds, including Li 2 S-GeS 2 , Li 2 S-GeS 2 -P 2 S 5wait.

[0112] The sulfide-based solid electrolyte may be a crystalline material or an amorphous material.

[0113] (Hydride-based solid electrolyte)

[0114] Examples of hydride-based solid electrolyte materials include 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 I. Li 2 NH, LiGd(BH 4 ) 3 Cl, Li 2 (BH 4 )(NH 2 )、Li 3 (NH 2 )I.Li 4 (BH 4 )(NH 2 ) 3 wait.

[0115] As the second solid electrolyte material, there can also be listed compounds obtained by replacing part or all of Li of the compounds listed as specific examples of oxide-based solid electrolytes, sulfide-based solid electrolytes, or hydride-based solid electrolytes with Na, K, Rb, or Cs.

[0116] The second electrolyte layer is formed of a second electrolyte composition. The second electrolyte layer may include a material different from that of the first electrolyte layer. The second electrolyte composition may include a solid electrolyte material and a polymer electrolyte, a binding resin, an organic solvent, an ionic liquid, etc. as required. The solid electrolyte material may include at least one of the first solid electrolyte material and the second solid electrolyte material described above, may include a second solid electrolyte material, and may include at least one of a sulfide-based solid electrolyte and an oxide-based solid electrolyte.

[0117] The thickness ratio of the first electrolyte layer to the second electrolyte layer ((thickness of the first electrolyte layer):(thickness of the second electrolyte layer)) may be 1:0.2 to 1:1, 1:0.3 to 1:1, or 1:0.5 to 1:1.

[0118] By having the first electrolyte layer and the second electrolyte layer, the interface between the positive electrode and the first electrolyte layer and the interface between the negative electrode and the second electrolyte layer are each formed to be able to perform good ion conduction. In addition, the ion conduction between the first electrolyte layer and the second electrolyte layer also becomes good. Through these, a battery that can perform good charge and discharge can be obtained.

[0119] This is derived from the characteristic that the first electrolyte layer has a small impedance strain (derived from the characteristic that it is mechanically flexible and can easily form a good interface).

[0120] Furthermore, since the first electrolyte layer has the characteristics of small strain and flexibility, cracks are less likely to occur inside the battery, which also contributes to obtaining good charge and discharge characteristics in that the ion conduction path is less likely to be interrupted.

[0121] The first electrolyte layer may have a region without microcracks exceeding 10 μm within 20 μm in the vertical direction (normal direction) from the interface between the positive electrode layer and the first electrolyte layer. In addition, a void structure may exist in this region.

[0122] The battery may also have a separator. The separator may be a porous material, such as a porous material made of resin. Specifically, porous polyolefin membranes, porous ceramic membranes, etc. may be mentioned.

[0123] The manufacturing method of the battery of the present embodiment is not particularly limited, but can be a method having the following steps: a step of pressurizing the positive electrode material to produce the positive electrode; and a step of pressurizing the first electrolyte composition to produce the first electrolyte layer. The step of pressurizing the positive electrode material to produce the positive electrode and the step of pressurizing the first electrolyte composition to produce the first electrolyte can also be performed simultaneously. In this case, the first electrolyte composition is arranged on the positive electrode material, and pressurization is performed together to produce the positive electrode and the first electrolyte layer. The second electrolyte layer can be formed by configuring the second electrolyte composition on the first electrolyte layer and pressurizing it. In addition, the negative electrode can be formed by configuring the negative electrode on the second electrolyte layer, or configuring the negative electrode material and pressurizing it.

[0124] Example

[0125] <Production of Solid Electrolyte Materials>

[0126] (Example 1)

[0127] In an argon atmosphere with a dew point of -70°C or less (hereinafter referred to as a dry argon atmosphere), LiCl and ZrCl 4 and LiBr were mixed in a molar ratio of 1.5:1:0.5 to prepare a raw material.

[0128] The raw materials were placed in a zirconia mortar for planetary ball milling, and 65 g of zirconia balls with a diameter of 4 mm were added. The solid electrolyte material (Li 2 O 2 ) was obtained by treating the solid electrolyte material (Li 2 O 2 ) in a mechanochemical reaction manner using a planetary ball mill (Verder Scientific Co., Ltd., PM 400) for 48 hours at 380 rpm. 2 ZrCl 5.5 Br 0.5 The ball mill was carried out in a mode in which the ball was rotated for 10 minutes and stopped for 1 minute at intervals, and the rotation direction was alternately switched between clockwise and counterclockwise.

[0129] <Production of Secondary Battery>

[0130] In a dry argon atmosphere, 29 parts by mass, 67 parts by mass, and 4 parts by mass of the solid electrolyte material of Example 1 and LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 and acetylene black, and mixed them in a mortar to obtain a mixture.

[0131] 100 mg of the solid electrolyte material of Example 1 and 15 mg of the above mixture were stacked in order in an insulating cylinder with an inner diameter of 10 mm to obtain a stacked body. A pressure of 200 MPa was applied to the stacked body to form the first electrode (layer of the above mixture) and the first solid electrolyte layer (layer of the solid electrolyte material of Example 1, 0.5 mm).

[0132] Next, 60 mg of 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 200 MPa was applied to the laminate to form a second solid electrolyte layer (0.3 mm). The first solid electrolyte layer was sandwiched between the first electrode and the second solid electrolyte layer.

[0133] Next, 60 mg of In foil was placed in contact with the second solid electrolyte layer, and 2 mg of Li foil was placed in contact with the In foil to obtain a stacked body. A pressure of 200 MPa was applied to the stacked body to form a second electrode.

[0134] A current collector made of stainless steel was attached to the first electrode and the second electrode, and then a lead was attached to the current collector. All components were placed in a desiccator and sealed, and the secondary battery of Example 1 was obtained in this manner.

[0135] <Charge and discharge test>

[0136] The test was carried out using the following product as a charge and discharge tester.

[0137] Charge and discharge tester: TOYO SYSTEM Co., Ltd. TOSCAT-3100

[0138] At 60°C, for the above secondary battery, the 2 )、1C(1.9mA / cm 2 ) and 3C(5.8mA / cm 2 ) were used to carry out charge and discharge tests at three C rates.

[0139] The battery was charged to 3.7 V at a current density corresponding to each C rate using constant current constant voltage (CCCV charging), and discharged to 1.9 V using a current density corresponding to each C rate.

[0140] Figure 1 The results of the charge and discharge test of the secondary battery of Example 1 are shown in FIG.

[0141] (Example 2)

[0142] LiCl and ZrCl 4 The solid electrolyte material (Li 2 ZrCl 6 ) were then prepared in the same manner and a charge and discharge test was performed. Figure 2 The results of the charge and discharge test of the secondary battery of Example 2 are shown in FIG.

[0143] (Example 3)

[0144] In an argon atmosphere with a dew point of -70°C or less (hereinafter referred to as a dry argon atmosphere), LiCl and ZrCl 4 、BiCl 3 、ZnCl 2 and LiBr becomes Li 2.05 Zr 0.96 Bi 0.03 Zn 0.01 Cl 5.7 Br 0.3 The raw materials are prepared by mixing the feed composition.

[0145] 1.2 g of the above raw material was placed in a zirconia pot for planetary ball milling, and 55 g of zirconia balls with a diameter of 4 mm and 15 g of zirconia balls with a diameter of 8 mm were added. The ball milling process was carried out at 300 rpm for 8 hours, 350 rpm for 8 hours, and 320 rpm for 8 hours using the planetary ball milling device, and the solid electrolyte material was obtained by treating it in a mechanochemical reaction manner. The ball milling was carried out in a mode of rotating for 10 minutes, stopping for 1 minute as an interval, and switching the rotation direction alternately between clockwise and counterclockwise.

[0146] (Example 4)

[0147] In an argon atmosphere having a dew point of -70°C or less (hereinafter referred to as a dry argon atmosphere), Li 2 O. Li 3 PO 4 , ZrCl 4 MgCl 2 Follow the steps below to become Li 2 Zr 0.95 Mg 0.05 Cl 3.9 O(PO 4 ) 0.033 The synthesis was carried out under the same conditions as in Example 3, except that the raw materials were prepared by mixing in a manner of the charging composition.

[0148] <Observation of Particles Using a Scanning Electron Microscope (SEM)>

[0149] The observation was performed using a scanning electron microscope JCM-7000 (manufactured by JEOL Ltd.) The particles of the produced solid electrolyte material were observed under the conditions of an accelerating voltage of 15 kV and a high vacuum mode.

[0150] <Measurement of resistance>

[0151] In a dry argon atmosphere, 29 parts by mass, 67 parts by mass, and 4 parts by mass of the solid electrolyte material of Example 3 and LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 and acetylene black, and mixed them in a mortar to obtain a mixture.

[0152] 100 mg of the solid electrolyte material of Example 3 and 15 mg of the above mixture were stacked in order in an insulating cylinder with an inner diameter of 10 mm to obtain a stacked body. A pressure of 200 MPa was applied to the stacked body to form the first electrode (layer of the above mixture) and the first solid electrolyte layer (layer of the solid electrolyte material of Example 3, 0.5 mm).

[0153] The laminate was sandwiched between two SUS plates and electrically connected to the terminals of an impedance analyzer (Sl1260 manufactured by Solatron Analytical). The resistance value was 274 Ω.

[0154] Similarly, the solid electrolyte material of Example 4 was used instead of the solid electrolyte material of Example 3, and a laminate was produced in the same manner as in Example 3, and impedance measurement was performed.

[0155] Based on the impedance measurement results, a Cole-Cole plot (Nyquist curve) graph was made. In the Cole-Cole plot, the real value of the impedance at the measurement point where the absolute value of the phase of the complex impedance is the smallest was regarded as the resistance value.

[0156] In addition, for the frequency at which the phase angle becomes the smallest in the Nyquist curve obtained by performing impedance measurement in the range of 0.1 Hz to 891 kHz, and the ratio A / B of the resistance value (A) of the impedance measurement to the resistance value (B) of the real part of the impedance at 891 kHz, they are summarized in Table 1.

[0157] (Comparative Example 1)

[0158] LiCl and YCl were used as raw materials 3 , and mixed at a molar ratio of 3:1 to prepare the raw materials. The same operation as in Example 1 was performed to obtain a solid electrolyte material (Li 3 YCl 6 ). Using the obtained solid electrolyte material, observation of the solid electrolyte material and the cross-section of the laminate using a scanning electron microscope and impedance measurement of the laminate were performed in the same manner as in Example 3. The resistance value was 2400 Ω.

[0159] Table 1

[0160] <![CDATA[频率 *1 ]]> <![CDATA[电阻值A(Ω) *2 ]]> <![CDATA[电阻值B(Ω) *3 ]]> A / B Micro cracks Example 3 250kHz 270 104.8 2.58 none Example 4 446kHz 107 71.4 1.50 none Comparative Example 1 71kHz 2400 665 3.61 have

[0161] *1: Frequency at which the phase angle becomes the smallest

[0162] *2: Resistance value of the real part of the impedance at the frequency at which the phase angle becomes the smallest

[0163] *3: Resistance value of the real part of the impedance at 891 kHz

[0164] <Cross-section observation using a scanning electron microscope (SEM)>

[0165] Observation was performed using a scanning electron microscope JCM-7000 (manufactured by JEOL Ltd.). Observation was performed under the conditions of an acceleration voltage of 15 kV and a high vacuum mode.

[0166] The measurement sample: Take out the laminate produced in the compression molding die as described above, cut it along the thickness direction, and observe its cross-section.

[0167] Figure 3 It is a scanning electron microscope image of the particles of the solid electrolyte material of Example 3. Figure 4 It is Figure 3 a figure obtained by magnifying a part of the particles. As can be seen from Figure 3 and Figure 4 , the particles of the solid electrolyte material of Example 1 have an uneven structure with a size of 0.5 - 2 μm.

[0168] In addition, Figure 5 it is a scanning electron microscope image of the cross-section of the laminate of Example 1. As shown in Figure 5 , although voids with a diameter of about 2 - 5 μm are seen, no large microcracks are seen in either the positive electrode layer or the solid electrolyte layer.

[0169] Figure 6 It is a scanning electron microscope image of the particles of the solid electrolyte material of Comparative Example 1. Figure 7 It is Figure 6 a figure obtained by magnifying a part of the particles in Figure 6 and Figure 7 . As can be seen from Figure 7 , no distinct uneven structure is seen in the particles of Comparative Example 1, and microcracks are seen in the part surrounded by the four corners of

[0170] In addition, Figure 8 it is a scanning electron microscope image of the cross-section of the laminate of Comparative Example 1. As shown in Figure 8 , although voids with a diameter of about 2 - 5 μm are seen, many microcracks are seen in both the positive electrode layer and the solid electrolyte layer, and the length of the microcracks in the solid electrolyte layer exceeds 10 μm (in the part surrounded by the four corners of Figure 8 ). In addition, Fig. 9 shows the Nyquist curves of the laminates of Example 3 and Comparative Example 1.

Claims

1. A battery, comprising a positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer is disposed between the positive electrode and the second electrolyte layer, the first electrolyte layer includes a material different from that of the second electrolyte layer, the first electrolyte layer includes a solid electrolyte material containing 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 the metalloid element other than the alkali metal element includes at least one of Zr and In.

2. The battery according to claim 1, wherein, in the Nyquist curve obtained by sandwiching the laminate composed of the positive electrode and the first electrolyte layer with two SUS plates and performing impedance measurement in the range of 0.1 Hz to 891 kHz, the frequency at which the phase angle becomes the minimum is 100 kHz to 891 kHz, and the ratio A / B of the resistance value (A) of the real part of the impedance measurement at the frequency at which the phase angle becomes the minimum to the resistance value (B) of the real part of the impedance at 891 kHz is 1.0 to 3.

5.

3. The battery according to claim 1 or 2, wherein, The solid electrolyte material contains A α M β Z γ D ζ O η represented compound in the formula, A is an alkali metal element, M is a metal element or a metalloid element other than the 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.

4. The battery according to claim 1 or 2, wherein, the second electrolyte layer includes at least one of an oxide-based solid electrolyte and a sulfide-based solid electrolyte.

5. The battery according to claim 1 or 2, wherein, the thickness ratio of the first electrolyte layer to the second electrolyte layer is 1:0.2 to 1:

1.

6. The battery according to claim 1 or 2, wherein, the first electrolyte layer further includes an ionic liquid.

7. A laminate, comprising a positive electrode and an electrolyte layer disposed on the positive electrode, wherein the electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer is disposed between the positive electrode and the second electrolyte layer, the first electrolyte layer includes a material different from that of the second electrolyte layer, the first electrolyte layer includes a solid electrolyte material containing 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 the metalloid element other than the alkali metal element includes at least one of Zr and In.

8. The laminate according to claim 7, wherein, in the Nyquist curve obtained by sandwiching the laminate composed of the positive electrode and the first electrolyte layer with two SUS plates and performing impedance measurement in the range of 0.1 Hz to 891 kHz, the frequency at which the phase angle becomes the minimum is 100 kHz to 891 kHz, and the ratio A / B of the resistance value (A) of the real part of the impedance measurement at the frequency at which the phase angle becomes the minimum to the resistance value (B) of the real part of the impedance at 891 kHz is 1.0 to 3.5.

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