Battery

Abstract

A battery provided with a laminate including a positive electrode layer and a solid electrolyte layer, the positive electrode layer containing a positive electrode active material and a solid electrolyte material, the solid electrolyte material containing an alkali metal element, a metal element or a semimetal element other than the alkali metal element, and a halogen element, a test piece is manufactured by punching the laminate into a cylindrical shape having a diameter of 10 mm, and the resistance value of the test piece when impedance measurement is performed by sandwiching the test piece with two SUS plates is 1000 Omega or less.

Description

Technical Field

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

[0002] Batteries such as lithium-ion batteries that charge and discharge with the movement of metal ions between the positive electrode and the negative electrode have been actively studied because of their high capacity. As an electrolyte for lithium-ion batteries and the like, a solution containing a lithium salt of an organic solvent or an ionic liquid is known, but research on solid electrolytes has been carried out from the viewpoints 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 Documents

[0004] Patent Documents

[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] Here, sometimes a solid electrolyte is also included in the positive electrode for the purpose of improving ionic conductivity. However, in the positive electrode having a conventional solid electrolyte, microcracks and the like are likely to occur inside the positive electrode.

[0009] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a battery in which microcracks and the like are not likely to occur inside the positive electrode.

[0010] Means for Solving the Problems

[0011] The present disclosure includes the following embodiments [1] to [6].

[0012] [1] A battery,

[0013] which includes a laminate having a positive electrode layer and a solid electrolyte layer,

[0014] wherein the positive electrode layer includes a positive electrode active material and a solid electrolyte material,

[0015] 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,

[0016] when a test piece is produced by punching the laminate into a cylindrical shape with a diameter of 10 mm and the resistance value when the test piece is sandwiched between two SUS plates for impedance measurement is 1000 Ω or less.

[0017] [2] A battery,

[0018] It has a laminate including a positive electrode layer and a solid electrolyte layer,

[0019] The above positive electrode layer includes a positive electrode active material and a solid electrolyte material,

[0020] The above 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,

[0021] In the Nyquist curve obtained by sandwiching the above laminate 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 smallest is 100 kHz to 891 kHz, and the ratio A / B of the resistance value (A) of the impedance measurement to the real part resistance value (B) of the impedance at 891 kHz is 1.0 to 3.5.

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

[0023] The above solid electrolyte material contains A α M β Z γ D ζ O η The compound represented by,

[0024] In the formula, A is an alkali metal, 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.

[0025] [4] The battery according to any one of [1] to [3], wherein,

[0026] The ratio of the volume of the positive electrode active material in the above positive electrode layer to the total volume of the positive electrode active material and the solid electrolyte material is 0.30 to 0.95.

[0027] [5] The battery according to any one of [1] to [4], wherein,

[0028] The above positive electrode layer further contains a binder resin.

[0029] [6] The battery according to any one of [1] to [5], wherein,

[0030] The above positive electrode active material is an alkali metal composite oxide containing nickel.

[0031] Advantages of the Invention

[0032] According to the present disclosure, a battery with a small resistance of the layer including the electrolyte layer can be provided. Description of the Drawings

[0033] Figure 1 It is a scanning electron microscope image of the solid electrolyte material of Example 1.

[0034] Figure 2 It is Figure 2 a figure obtained by magnifying a part of

[0035] Figure 3 It is a scanning electron microscope image of the cross-section of the laminate of Example 2.

[0036] Figure 4 It is a scanning electron microscope image of the solid electrolyte material of Comparative Example 1.

[0037] Figure 5 It is Figure 4 a figure obtained by magnifying a part of

[0038] Figure 6 It is a scanning electron microscope image of the cross-section of the laminate of Comparative Example 1.

[0039] Figure 7 It is the Nyquist curve of the laminates of Example 1 and Comparative Example 1. Detailed implementation mode

[0040] The battery of this implementation mode includes a laminate having a positive electrode layer and a solid electrolyte layer. The positive electrode layer contains a positive 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, and satisfies at least one of the following (1) and (2).

[0041] (1) When a test piece is produced by punching the laminate into a cylindrical shape with a diameter of 10 mm and the resistance value during impedance measurement by sandwiching the test piece with two SUS plates is 1000 Ω or less.

[0042] (2) In the Nyquist curve obtained by sandwiching the laminate 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 smallest 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 is 1.0 to 3.5.

[0043] Regarding (1), the resistance value can be 750 Ω or less, can be 500 Ω or less, and can be 300 Ω or less.

[0044] Regarding (2), the ratio A / B can be 1.0 to 3.0, and can be 1.0 to 2.8. In addition, the frequency at which the phase angle becomes the smallest can be 200 kHz or more, and can be 220 kHz or more.

[0045] The laminate can be a laminate obtained by adding 100 mg of a solid electrolyte layer to 15 mg of a positive electrode material (a composition forming a positive electrode) in a cylindrical container with a diameter of 10 mm and producing a compacted powder.

[0046] The positive electrode layer can be a positive electrode layer obtained by forming a layer containing a positive electrode material containing a positive electrode active material on a current collector. In addition, the negative electrode layer can be a negative electrode layer obtained by forming a layer containing a negative electrode material containing a negative electrode active material on a current collector. Examples of the battery include batteries that are charged and discharged by the movement of alkali metal ions, such as lithium ion batteries and sodium ion batteries. The battery can be a primary battery, a secondary battery, or an all-solid-state battery.

[0047] The solid electrolyte material contained in the positive electrode layer may contain an alkali metal element, a metal element or a metalloid element other than the alkali metal element, and a halogen element. Hereinafter, the 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 is also referred to as a first solid electrolyte material. The first solid electrolyte material can 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 the alkali metal element. (B) The first solid electrolyte material contains Zr as a metal element other than the alkali metal element and contains two or more halogen elements. (C) The first solid electrolyte material further contains an oxygen element.

[0048] The alkali metal element contained in the first solid electrolyte material can be any one of Li, Na, K, Rb, and Cs, but may contain at least one of Li, Na, and K, may contain at least one of Li and Na, and may contain Li.

[0049] Among the alkali metal elements contained in the first solid electrolyte material, the proportion of one alkali metal element can be 80 mol% or more, can be 90 mol% or more, and can be 95 mol% or more. This one alkali metal element can be at least one of Li, Na, and K, can be at least one of Li and Na, and can be Li.

[0050] The content of the alkali metal element in the first solid electrolyte material can be 15 to 30 mol%, can be 18 to 28 mol%, and can be 20 to 27 mol% relative to the total amount of atoms contained in the first solid electrolyte material.

[0051] As a metal element or a metalloid element other than an alkali metal element, elements with a valence of 2 to 5 can be cited, and one or more selected from the group consisting of elements with a valence of 3 and elements with a valence of 4 can be included. The first solid electrolyte material may contain one or two or more metal elements or metalloid elements other than an alkali metal element.

[0052] As the element with a valence of 2, alkaline earth metals, Zn, etc. can be cited. As the alkaline earth metal, at least one of Mg, Ca, Sr, and Ba can be used, at least one of Mg and Ca can be used, and Mg can be used. 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, Sb, etc. can be cited. As the element with a valence of 4, Zr, Ti, Hf, Sn, etc. can be cited, and Zr can be used. As the metal element with a valence of 5, Nb, Ta, etc. can be cited.

[0053] The metal element or the metalloid element other than the alkali metal element may contain at least one of In and Zr. The content of the metal element or the 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.

[0054] In the first solid electrolyte material, the total amount of Zr and In in terms of the amount of substance can be more than the total amount of substance of the alkali metal element, the metal element or the metalloid element other than Zr and In. It should be noted that when the first solid electrolyte material contains only one of Zr and In, the total amount of substance is the content of the contained element. The total amount of Zr and In in the first solid electrolyte material can be 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more of the total amount of substance of the metal element or the metalloid element other than the alkali metal element.

[0055] In the first solid electrolyte material, the content of Y in terms of the amount of substance can also be less than the total amount of Zr and In. It should be noted that when the first solid electrolyte material contains only one of Zr and In, the total amount of substance is the content of the contained element. The content of Y in the first solid electrolyte can be 40 mol% or less, 30 mol% or less, 20 mol% or less, or 10 mol% or less with respect to the total amount of substance of the metal element or the metalloid element other than the alkali metal element. The first solid electrolyte material may also substantially not contain Y.

[0056] 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, and 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, and may be In or Zr. In this case, the first solid electrolyte material contains metal elements or metalloid elements 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 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 one element is an element with a valence of 4, 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.

[0057] The halogen element contained in the first solid electrolyte material of this embodiment may be any one of F, Cl, Br, and I, but may contain at least one of Cl, Br, and I, may contain at least one of Cl and Br, and 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 a halogen element other than Cl and Cl, and may contain Cl and Br. The content of the halogen element other than Cl or Br relative to the total amount of halogen elements contained in the first solid electrolyte material may be 10 mol% or less, may be 0.1 to 10 mol%, and may be 1 to 8 mol%.

[0058] 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.

[0059] The first solid electrolyte material may contain 80 mol% or more of one element among the halogen elements, may contain 85 mol% or more, and may contain 90 mol% or more, relative to the total amount of the halogen elements. This 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 this one halogen element (also referred to as 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.

[0060] The first solid electrolyte material may contain at least one of P and S (also referred to as doping element X3). The content of 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%, or may be 0.3 to 1 mol% relative to the total amount of atoms contained in the first solid electrolyte material.

[0061] 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 it may be Zr. In addition, as doping element X2, it may also contain at least one of Hf and Mg.

[0062] The content of 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%, or may be 2 to 10 mol% of the content of the tetravalent metal element or metalloid element. The content of 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, or may be 8 mol% or less of the content of the tetravalent metal element or metalloid element.

[0063] The solid electrolyte material may have a hexagonal crystal structure and 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 the group consisting of Sc, La, Y, Ga, In, Bi, Sb, Ge, Zr, Sn, Nb, and Ta, and may contain Sc.

[0064] The first solid electrolyte material may contain a compound represented by the following formula (A).

[0065] A α M β Z γ D ζ O η (A)

[0066] Wherein, 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.

[0067] Examples of the compound represented by formula (A) include compounds represented by the following formulas (1) to (3).

[0068] Aα1 M β1 Z 6-δ1 X1 ε11 X2 ε12 (1)

[0069] A α2 M β2 X2 ε21 Z 6-γ2 X1 ε22 (2)

[0070] A α3 M β3 X1 ε31 Z δ3 D ζ O η (3)

[0071] In Formula (1), A, M, and Z are an alkali metal element, a trivalent metal element or a semi-metal element, and a halogen element, respectively. As specific examples, the above elements can be cited. M preferably contains In. X1 and X2 are a doping element X1 and a doping element X2, respectively. As specific examples, the above elements 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.

[0072] In Formula (2), A, M, and Z are an alkali metal element, a tetravalent metal element or a semi-metal element, and a halogen element, respectively. As specific examples, the above elements can be cited. M preferably contains Zr. X1 and X2 are a doping element X1 and a doping element X2, respectively. As specific examples, the above elements can be cited. It can be 1.6 ≤ α2 ≤ 2.5, can be 1.8 ≤ α2 ≤ 2.4, and can be 2 ≤ α2 ≤ 2.3. It can be 0 < β2 ≤ 1.1, can be 0.5 ≤ β2 ≤ 1, and can be 0.8 ≤ β2 ≤ 1. It can be 0 ≤ γ2 < 1, can be 0.01 ≤ γ2 ≤ 0.8, can be 0.02 ≤ γ2 ≤ 0.7, can be 0.1 ≤ γ2 ≤ 0.6, and can be 0.2 ≤ γ2 ≤ 0.6. It can be 0 ≤ ε21 ≤ 0.7, can be 0 < ε21 ≤ 0.5, and can be 0.01 ≤ ε21 ≤ 0.3. It can be 0 ≤ ε22 ≤ 0.8, and can be 0 < ε21 ≤ 0.6. When X2 is iodine, it can be 0.01 ≤ ε21 ≤ 0.3, and can be 0.015 ≤ ε21 ≤ 0.1.

[0073] 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, the above elements can be cited. M preferably contains Zr. X1 and D are a doping element X1 and a doping element X3, respectively. As specific examples, the above elements 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 ≤ β ≤ 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.

[0074] The first solid electrolyte material can be in a particle shape. In this case, the average particle diameter 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. In the particles of the first solid electrolyte material, microcracks with a size of 0.5 μm or more may not exist.

[0075] As a method for manufacturing the first solid electrolyte material, there is no particular limitation. For example, a method including a step of ball-milling the raw materials can be cited. Annealing can also be performed on the product after ball-milling. In addition, in the case of obtaining a hexagonal solid electrolyte material, the manufacturing method of the first solid electrolyte material can also be a method including a step of heating the raw materials under a pressure of 1 GPa or more.

[0076] There is no particular limitation on the raw materials. For example, they can be compounds containing an alkali metal halide, a chloride of a metal element or a metalloid element other than an alkali metal, and a doping element 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).

[0077] There is no particular limitation on the conditions for ball-milling, but it can be set to 10 to 100 hours at a rotation speed of 200 to 700 rpm. The rotation speed can be 250 to 600 rpm, or can be 300 to 500 rpm. The pulverization time is preferably 24 hours to 72 hours, and more preferably 36 to 60 hours.

[0078] As the balls for ball milling, there is no particular limitation, but zirconia balls can be used. As for the size of the balls used, there is no particular limitation, but balls with a size of 2 mm to 10 mm can be used.

[0079] As the balls, it is preferable to combine balls of two or more sizes.

[0080] For example, balls with a diameter of 4 mm can be combined with balls with a diameter of 8 mm. In this case, it is preferable that the total weight of the balls with a size of 4 mm is greater than the total weight of the balls with a size of 8 mm.

[0081] By performing ball milling for the above-mentioned time, each raw material is sufficiently mixed, promoting mechanical chemical reactions, and thereby the ionic conductivity of the resulting compound can be improved.

[0082] The ball milling can have multi-stage processes with different rotation speeds. For example, the process of performing ball milling can successively have a first process, a second process, and a third process, and 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.

[0083] Annealing is preferably performed in an inert atmosphere or in a vacuum. As the annealing temperature, for example, it is preferably 150 to 300 °C, more preferably 200 to 250 °C. As the annealing time, for example, it can be 1 to 10 hours, preferably 3 to 6 hours.

[0084] As the positive electrode active material, there is no particular limitation, and examples thereof include alkali metal-containing 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 can be at least one selected from the group consisting of V, Cr, Mn, Fe, Co, Ni, and Cu, and Ni can be included. For example, in the case where the alkali metal element is lithium (i.e., in the case of a lithium-containing 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]), LiCr0.5 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 etc. When the positive electrode active material in the positive electrode material contains an alkali metal element other than Li, as specific examples thereof, substances obtained by replacing Li in the above specific examples with other alkali metals can be cited. As alkali metals other than Li, Na or K can be cited.

[0085] The content of the positive electrode active material in the positive electrode material 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 positive electrode material. The content of the positive electrode active material in the positive electrode material can be 99% by mass or less, can be 95% by mass or less, and can be 90% by mass or less. In addition, the content of the positive electrode active material in the positive electrode material can be 50 to 99% by mass, can be 60 to 95% by mass, and can be 70 to 90% by mass. The ratio of the volume of the positive electrode active material in the positive electrode layer to the total volume of the positive electrode active material and the solid electrolyte material can be 0.30 to 0.95.

[0086] The positive electrode layer (positive electrode material) of the present embodiment may further contain a binder resin (adhesive), a conductive additive, etc. There is no particular limitation on the binder resin, but fluororesins can be cited. As the fluororesin, a resin having a carbon chain as the main chain is preferred. The carbon chain can be a carbon chain 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 positive electrode layer can be 0.5 to 10% by mass, and can be 1 to 7% by mass.

[0087] Examples of the conductive additive include carbon materials such as natural graphite (flake graphite, etc.) and artificial graphite; carbon blacks such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and pyrolytic carbon black; carbon fibers; etc. The content of the conductive additive in the positive electrode layer can be 0.5 to 10% by mass, and can be 1 to 7% by mass.

[0088] The solid electrolyte material contained in the positive electrode layer can be one or two of the above-mentioned first solid electrolyte material and second solid electrolyte material.

[0089] The positive electrode layer can have a region within 20 μm in the vertical direction (normal direction) from the interface between the positive electrode layer and the solid electrolyte layer and having no microcracks exceeding 10 μm. In addition, a void structure can exist in this region.

[0090] The negative electrode material can contain a negative electrode active material and, as required, a polymer electrolyte, a binder resin, a conductive additive, an organic solvent, an ionic liquid, etc.

[0091] Examples of the negative electrode active material include elemental substances of alkali metal elements, Si, P, Sn, Si-Mn, Si-Co, Si-Ni, In, Au, etc., alloys or composites containing these elements, carbon materials such as graphite, substances obtained by intercalating alkali metal ions between the layers of the carbon material, and oxides containing titanium, etc. The alkali metal element can be Li, Na, or K, can be Li or Na, and can be Li.

[0092] As the oxide containing titanium, it can be a compound represented by the compositional formula: A s TiO t (where 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.

[0093] The solid electrolyte layer can be a layer formed from an electrolyte composition. The electrolyte composition can contain a solid electrolyte material and, as required, 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 a solid electrolyte material other than the first solid electrolyte material (second solid electrolyte material).

[0094] 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), or the like. The second solid electrolyte material can contain an alkali metal element.

[0095] (Oxide-based solid electrolyte)

[0096] As the oxide-based solid electrolyte, for example, perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, garnet-type oxides and other oxides, and substances obtained by doping other cations or anions into the oxides can be cited.

[0097] As the perovskite-type oxide, Li 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.

[0098] As the NASICON-type oxide, Li 1+d Al d Ti 2-d (PO 4 ) 3 (0 ≤ d ≤ 1), etc. The NASICON-type oxide is an oxide represented by Li m M 1 n M 2 o P p O q (wherein, M 1 is one or more elements selected from the group consisting of B, Al, Ga, In, C, Si, Ge, Sn, Sb and Se. M 2 is 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 optional positive numbers.) The oxides represented can be cited as 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.

[0099] As the LISICON-type oxide, Li 4 M 3 O 4 -Li 3 M 4 O 4 (M 3 is one or more elements selected from the group consisting of Si, Ge and Ti. M4 is one or more elements selected from the group consisting of P, As, and V. Oxides and the like represented by

[0100] As the garnet-type oxide, Li 7 La 3 Zr 2 O 12 (LLZ), Li 7-a2 La 3 Zr 2-a2 Ta a2 O 12 (LLZT, 0 < a2 < 1 can be, 0.1 < a2 < 0.8 can be, 0.2 < a2 < 0.6), etc., Li-La-Zr-based oxides and the like.

[0101] The oxide-based solid electrolyte can be a crystalline material or an amorphous material.

[0102] As the oxide-based solid electrolyte, Li 6.6 La 3 Zr 1.6 Ta 0.4 O 12 、Li 0.33 La 0.55 TiO 3 etc.

[0103] (Sulfide-based solid electrolyte)

[0104] As the sulfide-based solid electrolyte, 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 S12 etc.

[0105] It should be noted that in this specification, the expression "system compound" referring to a sulfide-based solid electrolyte is used as a general term for solid electrolytes mainly containing the "Li" described before the "system compound". 2 S, P 2 S 5 ", etc. as raw materials. For example, for Li 2 S-P 2 S 5 system compounds, it includes solid electrolytes containing Li 2 S and P 2 S 5 and further containing other raw materials. In addition, for Li 2 S-P 2 S 5 system compounds, it also includes solid electrolytes with different mixing ratios of Li2S and P2S5.

[0106] 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 and n are positive numbers. Z is Ge, Zn or Ga), etc.

[0107] 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, 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, y are positive numbers. M is P, Si, Ge, B, Al, Ga or In, etc.)

[0108] As Li 2 S - GeS 2 series compounds, Li 2 S - GeS 2 、Li 2 S - GeS 2 -P 2 S 5 etc.

[0109] The sulfide - based solid electrolyte can be a crystalline material or an amorphous material.

[0110] (Hydride - based solid electrolyte)

[0111] 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 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 etc.

[0112] As the second solid electrolyte material, compounds obtained by substituting part or all of the Li in 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 can also be cited.

[0113] The battery can also have a separator. The separator can be a porous material and can be a resinous porous material. Specifically, porous polyolefin membranes, porous ceramic membranes, etc. can be cited.

[0114] The manufacturing method of the battery of the present embodiment is not particularly limited, but it can be a method having the following steps: a step of manufacturing a positive electrode by pressing a positive electrode material; and a step of manufacturing a solid electrolyte layer by pressing an electrolyte composition. The step of manufacturing a positive electrode by pressing a positive electrode material and the step of manufacturing a solid electrolyte by pressing an electrolyte composition can also be carried out simultaneously. In this case, the first electrolyte composition is disposed on the positive electrode material, and pressing is carried out simultaneously to manufacture the positive electrode and the solid electrolyte layer. In addition, the negative electrode can be formed by disposing a negative electrode on the solid electrolyte layer or by disposing a negative electrode material and pressing.

[0115] Examples

[0116] (Example 1)

[0117] In an argon atmosphere having a dew point of -70°C or lower (hereinafter, referred to as a dry argon atmosphere), LiCl, ZrCl 4 , BiCl 3 , ZnCl 2 and LiBr were mixed in such a way as to achieve the feeding composition of Li 2.05 Zr 0.96 Bi 0.03 Zn 0.01 Cl 5.7 Br 0.3 to prepare raw materials.

[0118] Place 1.2 g of the above raw materials in a zirconia mortar for planetary ball milling, and add 55 g of zirconia balls with a diameter of 4 mm and 15 g of zirconia balls with a diameter of 8 mm. By using the above planetary ball milling device, perform ball milling operations successively for 8 hours at 300 rpm, 8 hours at 350 rpm, and 8 hours at 320 rpm, and process in a manner that mechanical chemical reactions occur to obtain a solid electrolyte material. The ball milling is carried out in a mode where it stops for 1 minute every 10 minutes of rotation and the rotation direction is alternately switched between clockwise and counterclockwise.

[0119] <Observation of Particles by Scanning Electron Microscope (SEM)>

[0120] Use a scanning electron microscope JCM-7000 (manufactured by JEOL Ltd.) for observation. Observe the particles of the fabricated solid electrolyte material under the conditions of an acceleration voltage of 15 kV and a high vacuum mode.

[0121] <Measurement of Resistance Value>

[0122] In a dry argon atmosphere, weigh 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 mix them in a mortar to obtain a mixture.

[0123] Stack 100 mg of the solid electrolyte material of Example 1 and 15 mg of the above mixture successively in an insulating cylinder with an inner diameter of 10 mm to obtain a laminate. Apply a pressure of 370 MPa 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, 0.5 mm).

[0124] Next, prepare a compression molding die having a frame type, a lower punch, and an upper punch. It should be noted that the frame type is formed of insulating polycarbonate. In addition, both the upper punch and the lower punch are formed of electrically conductive stainless steel (SUS) and are electrically connected to the terminals of an impedance analyzer (Sl1260 manufactured by Solatron Analytical) respectively.

[0125] Using the above-mentioned compression molding die, the ionic conductivity was measured by the following method. First, in a dry argon atmosphere, each electrolyte material of the examples and comparative examples was filled onto the lower part of the punch inserted vertically downward into the hollow part of the frame type. Then, by pressing the upper part of the punch into the hollow part of the frame type from above, a pressure of 370 MPa was applied to the electrolyte material inside the compression molding die. After applying the pressure, the punch was fixed by tightening it from above and below with a clamp. In a state of maintaining a constant pressure, using the above-mentioned impedance analyzer, the impedance of the electrolyte material at 25 °C was measured by electrochemical impedance measurement method.

[0126] From the impedance measurement results, a chart of the Cole-Cole plot (Nyquist curve) 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.

[0127] 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.

[0128] <Cross-sectional Observation Using Scanning Electron Microscope (SEM)>

[0129] Observation was carried out using a scanning electron microscope JCM-7000 (manufactured by JEOL Ltd.). Observation was carried out under the conditions of an acceleration voltage of 15 kV and a high vacuum mode.

[0130] As for the measurement sample, the laminate produced in the compression molding die as described above was taken out, cut along the thickness direction, and its cross-section was observed.

[0131] (Example 2)

[0132] In an argon atmosphere having a dew point of -70 °C or lower (hereinafter, referred to as a dry argon atmosphere), Li 2 О, Li 3 PO 4 , ZrCl 4 , MgCl 2 were mixed in such a way as to have a feeding composition of Li 2 Zr 0.95 Mg 0.05 Cl 3.9 O(PO 4 ) 0.033 to prepare raw materials. Except for this, synthesis was carried out under the same conditions as in Example 1, and impedance measurement was performed.

[0133] (Comparative Example 1)

[0134] As raw materials, LiCl and YCl 3 were used and mixed at a molar ratio of 3:1 to prepare the raw materials. The same operations as in Example 1 were carried out to obtain a solid electrolyte material (Li 3 YCl 6 ). Using the obtained solid electrolyte material, a laminate was fabricated in the same manner as in Example 1, and observations of the cross-sections of the solid electrolyte material and the laminate were made using a scanning electron microscope, and the resistance value of the laminate was measured. The resistance value was 2400 Ω.

[0135] Table 1

[0136] <![CDATA[Frequency *1 > <![CDATA[Resistance value A (Ω) *2 > <![CDATA[Resistance value B (Ω) *3 > A / B microcrack Example 1 250 kHz 270 104.8 2.58 none Example 2 446 kHz 107 71.4 1.50 none Comparative Example 1 71 kHz 2400 665 3.61 yes

[0137] *1: Frequency at which the phase angle becomes minimum

[0138] *2: Resistance value of the real part of the impedance at the frequency at which the phase angle becomes minimum

[0139] *3: Resistance value of the real part of the impedance at 891 kHz (Ω)

[0140] Figure 1 is a scanning electron microscope image of the particles of the solid electrolyte material of Example 1. Figure 2 is a figure obtained by magnifying a part of Figure 1 . As can be seen from Figure 1 and Figure 2 , the particles of the solid electrolyte material of Example 1 have an uneven structure with a size of 0.5 - 2 μm.

[0141] In addition, Figure 3 is a scanning electron microscope image of the cross-section of the laminate of Example 1. As shown in Figure 3 , 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.

[0142] Figure 4 is a scanning electron microscope image of the particles of the solid electrolyte material of Comparative Example 1. Figure 5 is a figure obtained by magnifying a part of Figure 4 . As can be seen from Figure 5 , 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 Figure 5 .

[0143] In addition, Figure 6 is a scanning electron microscope image of the cross-section of the laminate of Comparative Example 1. As shown in Figure 6As shown, voids with a diameter of about 2 to 5 μm are observed, but many microcracks are observed 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 (the part surrounded by the four corners of Figure 6 ). In addition, Figure 7 shows the Nyquist curves of the laminate of Example 1 and the laminate of Comparative Example 1 described later.

Claims

1. A battery comprising a laminate including a positive electrode layer and a solid electrolyte layer, wherein the positive electrode layer contains a positive 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, when a test piece is produced by punching the laminate into a cylindrical shape with a diameter of 10 mm and the resistance value during impedance measurement while the test piece is clamped between two SUS plates is 1000 Ω or less.

2. A battery comprising a laminate including a positive electrode layer and a solid electrolyte layer, wherein the positive electrode layer contains a positive 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, in the Nyquist curve obtained by performing impedance measurement in the range of 0.1 Hz to 891 kHz while the laminate is clamped 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 at which the phase angle becomes minimum to the real part resistance value (B) 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, 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 ratio of the volume of the positive electrode active material in the positive electrode layer to the total volume of the positive electrode active material and the solid electrolyte material is 0.30 to 0.

95.

5. The battery according to claim 1 or 2, wherein, the positive electrode layer further contains a binder resin.

6. The battery according to claim 1 or 2, wherein, the positive electrode active material is an alkali metal-containing composite oxide containing nickel.

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