Electrode plate and battery

Abstract

An electrode plate (1000) according to the present disclosure is provided with a current collector (100) having a substrate (101) and a coating layer (102) covering the substrate (101), and an electrode layer (110) disposed on the current collector (100), the coating layer (102) containing conductive carbon (103) and a first binder (104), the electrode layer (110) containing a second binder (113), the first binder (104) containing an aromatic super-engineering plastic, and the second binder (113) containing an aromatic super-engineering plastic. The second adhesive (113) contains a styrene-based elastomer in which the molar fraction of repeating units derived from styrene is 0.18 or more.

Description

Technical Field

[0001] The present disclosure relates to an electrode plate and a battery. Background Art

[0002] A current collector is an indispensable component in electrochemical devices such as batteries and capacitors. An electrode layer such as an active material layer is disposed on the current collector. The adhesion between the current collector and the electrode layer affects the performance of the electrochemical device. As a current collector capable of improving the adhesion, a current collector having a substrate and a coating layer is known.

[0003] In Patent Document 1, an electrode plate is disclosed which includes a current collector having a coating layer containing polyimide and an electrode layer provided on the surface of the current collector. The electrode layer contains styrene-butadiene rubber (SBR).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2010-153224 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] An object of the present disclosure is to provide an electrode plate suitable for improving the peel strength between an electrode layer and a current collector.

[0009] Means for Solving the Problems

[0010] The present disclosure provides an electrode plate including: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing conductive carbon and a first binder, the electrode layer containing a second binder, the first binder containing an aromatic super engineering plastic, and the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.18 or more.

[0011] Effects of the Invention

[0012] According to the present disclosure, an electrode plate suitable for improving the peel strength between an electrode layer and a current collector can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a cross-sectional view of the electrode plate according to Embodiment 1.

[0014] Figure 2 It is a cross-sectional view of the battery according to Embodiment 2.

[0015] Figure 3 It is a cross-sectional view of the battery according to the modification. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments.

[0017] (Embodiment 1)

[0018] Figure 1 FIG. is a cross-sectional view of the electrode plate 1000 according to Embodiment 1. The electrode plate 1000 includes a current collector 100 and an electrode layer 110. The current collector 100 has a substrate 101 and a coating layer 102. The coating layer 102 covers the substrate 101 and contacts the electrode layer 110. The coating layer 102 contains conductive carbon 103 and a first binder 104. The electrode layer 110 contains a second binder 113. The first binder 104 contains an aromatic super engineering plastic. The second binder 113 contains a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.18 or more.

[0019] According to the above configuration, the peel strength between the electrode layer 110 and the current collector 100 is improved. Furthermore, the cycle characteristics of the battery including the electrode plate 1000 can be improved. The electrode plate 1000 can be used as an electrode plate for electrochemical devices such as non-aqueous electrolyte batteries, solid-state batteries, and capacitors. The electrode plate 1000 is particularly suitable as an electrode plate for all-solid-state secondary batteries.

[0020] In the electrode plate 1000, the reason for the improvement in the peel strength between the electrode layer 110 and the current collector 100 is not necessarily clear, but it is presumed that the interaction between the aromatic rings contained in the styrene-based elastomer (second binder) and the aromatic rings contained in the aromatic super engineering plastic (first binder) has an effect. As such an interaction, π-π interaction can be cited.

[0021] According to the electrode plate 1000 of the present embodiment, the electrode layer 110 contacts the coating layer 102. The electrode layer 110 has a second binder 113 containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.18 or more. The coating layer 102 has a first binder 104 containing an aromatic super engineering plastic. Therefore, the interaction between the aromatic rings of the styrene-based elastomer contained in the second binder 113 and the aromatic rings contained in the aromatic super engineering plastic contained in the first binder 104 easily occurs.

[0022] The electrode layer 110 may contain a solid electrolyte 111, may contain an active material 112, or may contain both.

[0023] [Current Collector]

[0024] The current collector 100 includes a substrate 101 and a coating layer 102. The coating layer 102 contains an aromatic super engineering plastic. Due to the interaction between the aromatic rings of the aromatic super engineering plastic and the aromatic rings of the styrene-based elastomer contained in the electrode layer 110, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase.

[0025] The current collector 100 has, for example, a plate-like or foil-like shape. The thickness of the current collector 100 can be 0.1 μm or more and 1 mm or less, can also be 1 μm or more and 100 μm or less, and can also be 10 μm or more and 50 μm or less. When the thickness of the current collector 100 is 0.1 μm or more, the breakage of the current collector 100 is suppressed due to the increased strength of the current collector 100. When the thickness of the current collector 100 is 1 mm or less, the energy density of the electrochemical device can be increased by lightening the current collector 100. That is, by appropriately adjusting the thickness of the current collector 100, an electrochemical device can be stably manufactured and the energy density of the electrochemical device can be increased.

[0026] <Coating layer>

[0027] The coating layer 102 can entirely cover the main surface of the substrate 101, or can partially cover the main surface of the substrate 101. The "main surface" refers to the surface of the substrate 101 having the largest area. The coating layer 102 is located between the substrate 101 and the electrode layer 110 and contacts the substrate 101 and the electrode layer 110 respectively. The shape of the coating layer 102 can be dot-like, strip-like, etc.

[0028] Examples of the conductive carbon 103 contained in the coating layer 102 include graphite-based materials such as natural graphite and artificial graphite, carbon black-based materials such as acetylene black (AB) and Ketjen black (KB), conductive fiber-based materials such as carbon fiber (CF), vapor grown carbon fiber (VGCF (registered trademark)), and carbon nanotube (CNT), and nano-carbon materials such as graphene. As the conductive carbon, one conductive carbon selected from the above can be used alone, or two or more conductive carbons selected from the above can be used.

[0029] The first binder 104 contained in the coating layer 102 includes an aromatic super engineering plastic. The so-called aromatic super engineering plastic refers to an engineering plastic that contains an aromatic ring in the main chain skeleton and has a continuous use temperature of 150 °C or higher. Examples of the aromatic super engineering plastic include polybenzimidazole (PBI), polyimide (PI), polyetherketoneetherketoneketone (PEKEKK), polyamideimide (PAI), polyetheretherketone (PEEK), polyetherketone (PEK), liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyethersulfone (PES), polyphenylsulfone (PPSU), polyetherimide (PEI), polysulfone (PSU), polyparaphenylene (PPP), polyarylate (PAR), etc. As the first binder 104, a mixture containing two or more selected from the above can be used. The aromatic super engineering plastic exhibits high heat resistance. Therefore, when the aromatic super engineering plastic is included in the coating layer 102 as the first binder 104, even if the member including the current collector 100 is compressed at a high temperature, the coating layer 102 is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0030] The aromatic super engineering plastic can be polyimide (PI). Polyimide has a tendency to exhibit higher heat resistance. Therefore, even if the member including the current collector 100 is compressed at a high temperature, the coating layer 102 is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0031] The first binder 104 may include a supplementary binder other than the aromatic super engineering plastic. Alternatively, the first binder 104 can be an aromatic super engineering plastic. In other words, the first binder 104 can only include the aromatic super engineering plastic.

[0032] Examples of supplementary adhesives include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyethylene, polypropylene, aromatic polyamide resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, methyl polyacrylate, ethyl polyacrylate, hexyl polyacrylate, polymethacrylic acid, polymethyl methacrylate (PMMA), ethyl polymethacrylate, hexyl polymethacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polycarbonate, polyethersulfone, polyether ketone, polyether ether ketone, polyphenylene sulfide, hexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, ethyl cellulose, etc. As supplementary adhesives, copolymers synthesized from two or more monomers selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, butadiene, isoprene, styrene, pentafluoropropylene, fluoromethyl vinyl ether, acrylate, acrylic acid, and hexadiene can also be used. As supplementary adhesives, one selected from the above can be used alone, or a mixture containing two or more selected from the above can be used.

[0033] From the viewpoint of excellent adhesiveness, the supplementary adhesive may contain an elastomer. An elastomer refers to a polymer having rubber elasticity. The elastomer used as an adhesive can be a thermoplastic elastomer or a thermosetting elastomer. As elastomers, in addition to the above-mentioned styrene-based elastomers, butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), hydrogenated isoprene rubber (HIR), hydrogenated butyl rubber (HIIR), hydrogenated nitrile rubber (HNBR), acrylate-butadiene rubber (ABR), etc. can be cited. A mixture containing two or more selected from the above can be used.

[0034] There is no particular limitation on the content rate of the first adhesive 104 in the coating layer 102. For example, it is 20% by mass or more and 95% by mass or less, or it can be 40% by mass or more and 90% by mass or less, or it can be 55% by mass or more and 85% by mass or less. When the content rate of the first adhesive 104 is 95% by mass or less, the conductivity of the coating layer 102 is improved, and thus high output of the electrochemical device can be achieved. When the content rate of the first adhesive 104 is 20% by mass or more, the first adhesive 104 and the like are sufficiently present, so there is a tendency to suppress peeling of the coating layer 102.

[0035] The coating layer 102 may contain a conductive material other than the conductive carbon 103. Examples of conductive materials other than conductive carbon include conductive fiber materials such as metal fibers, conductive powder materials such as carbon fluoride and aluminum, conductive whisker materials such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene.

[0036] The coating layer 102 may contain other elements or components in addition to the conductive carbon 103 and the first binder 104. The other elements or components may be added to the coating layer 102 by contamination or the like. For example, an inevitable oxide film or the like may be formed on a part of the surface of the coating layer 102. That is, the coating layer 102 may contain inevitable oxides or the like.

[0037] The coating layer 102 can be produced, for example, by a method of sputtering the material of the coating layer 102 onto the surface of the substrate 101. The coating layer 102 can be produced by coating a solution or dispersion containing the material of the coating layer 102 on the surface of the substrate 101. The coating of the solution or dispersion can be carried out using a gravure coater, a slot die coater, or the like.

[0038] There is no particular limitation on the mass per unit area of the coating layer 102. For example, it can be 0.01 g / m 2 or more and 5 g / m 2 or less, and can also be 0.1 g / m 2 or more and 3 g / m 2 or less, and can also be 0.5 g / m 2 or more and 2 g / m 2 or less. When the mass per unit area is 0.01 g / m 2 or more, contact between the substrate 101 and the electrode layer can be prevented, thereby suppressing corrosion of the substrate 101. When the mass per unit area is 5 g / m 2 or less, the resistance of the coating layer 102 is reduced, and for an electrochemical device, operation at high output can be easily performed.

[0039] There is no particular limitation on the thickness of the coating layer 102. For example, it can be 0.001 μm or more and 10 μm or less, can also be 0.01 μm or more and 5 μm or less, and can also be 0.1 μm or more and 3 μm or less. When the thickness of the coating layer 102 is 0.001 μm or more, contact between the substrate 101 and the electrode layer 110 can be prevented, thereby suppressing corrosion of the substrate 101. When the thickness of the coating layer 102 is 10 μm or less, the resistance of the coating layer 102 is reduced, and for an electrochemical device, operation at high output can be easily performed.

[0040] <Substrate>

[0041] The substrate 101 has, for example, a foil shape or a plate shape. As the material of the substrate 101, a metal or an alloy can be used. As the metal, aluminum, iron, nickel, copper, etc. can be cited. As the alloy, aluminum alloy, stainless steel (SUS), etc. can be cited. The substrate 101 may contain aluminum or an aluminum alloy.

[0042] The substrate 101 may contain aluminum as the main component. "The substrate 101 contains aluminum as the main component" means that the content rate of aluminum in the substrate 101 is 50% by mass or more. Aluminum is a lightweight metal with high electrical conductivity. Therefore, the electrode plate 1000 having the substrate 101 containing aluminum as the main component can improve the weight energy density of the electrochemical device. The substrate 101 containing aluminum as the main component may further contain elements other than aluminum. It should be noted that when the substrate 101 contains only aluminum, that is, when the content rate of aluminum in the substrate 101 is 100%, sometimes the strength of the substrate 101 decreases. Therefore, the substrate 101 may contain elements other than aluminum. The content rate of aluminum in the substrate 101 may be 99% by mass or less, or may be 90% by mass or less.

[0043] The substrate 101 may contain an aluminum alloy. The aluminum alloy is lightweight and has high strength. Therefore, the electrode plate 1000 having the substrate 101 containing an aluminum alloy can realize an electrochemical device having both high weight energy density and high durability. There is no particular limitation on the aluminum alloy, and examples thereof include Al-Cu alloy, Al-Mn alloy, Al-Mn-Cu alloy, Al-Fe-Cu alloy, etc.

[0044] As the material of the substrate 101, an Al-Mn alloy can be used. The Al-Mn alloy has high strength and excellent formability and corrosion resistance. Therefore, the electrode plate 1000 having the substrate 101 containing an Al-Mn alloy can improve the cycle characteristics of the battery.

[0045] There is no particular limitation on the thickness of the substrate 101. For example, it is 0.1 μm or more and 50 μm or less, or may be 1 μm or more and 30 μm or less. When the thickness of the substrate 101 is 0.1 μm or more, the strength of the substrate 101 is improved, and thus breakage of the substrate 101 is suppressed. When the thickness of the substrate 101 is 50 μm or less, the mass of the substrate 101 is reduced, and the mass energy density of the electrochemical device can be improved.

[0046] [Electrode layer]

[0047] The electrode layer 110 contains a second binder 113. The electrode layer 110 may further contain a solid electrolyte 111 and an active material 112. Hereinafter, the solid electrolyte 111, the active material 112, and the second binder 113 will be described in detail.

[0048] <Solid electrolyte>

[0049] The solid electrolyte 111 may contain a sulfide solid electrolyte. The sulfide solid electrolyte may contain lithium. By using a sulfide solid electrolyte having lithium as the solid electrolyte 111, a lithium secondary battery using the electrode plate 1000 containing the sulfide solid electrolyte can be manufactured.

[0050] The solid electrolyte 111 may include solid electrolytes other than sulfide solid electrolytes, such as oxide solid electrolytes, halide solid electrolytes, polymer solid electrolytes, and complex hydride solid electrolytes. Alternatively, the solid electrolyte 111 may be a sulfide solid electrolyte. In other words, the solid electrolyte 111 may only include sulfide solid electrolytes.

[0051] In the present disclosure, the so-called "oxide solid electrolyte" refers to a solid electrolyte containing oxygen. The oxide solid electrolyte may further include anions other than sulfur and halogen elements as anions other than oxygen.

[0052] In the present disclosure, the so-called "halide solid electrolyte" refers to a solid electrolyte containing halogen elements and not containing sulfur. In the present disclosure, the so-called solid electrolyte not containing sulfur refers to a solid electrolyte represented by a compositional formula not containing sulfur elements. Therefore, a solid electrolyte with an extremely small amount of sulfur component, for example, a solid electrolyte with sulfur of 0.1% by mass or less, is included in the solid electrolyte not containing sulfur. The halide solid electrolyte may further include oxygen as an anion other than halogen elements.

[0053] As the sulfide solid electrolyte, for example, Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 etc. Among these, LiX, Li2O, MO q 、Li p MO q etc. can be added. The element X in "LiX" is at least one selected from F, Cl, Br, and I. The element M in "MO q " and "Li p MO q " is at least one selected from P, Si, Ge, B, Al, Ga, In, Fe, and Zn. The p and q in "MO q " and "Li p MO q " are each independently a natural number.

[0054] As the sulfide solid electrolyte, for example, Li2S-P2S5-based glass ceramics can be used. In the Li2S-P2S5-based glass ceramics, LiX, Li2O, MO q 、Li p MO qetc., and two or more selected from LiCl, LiBr, and LiI can be added. Since the Li2S-P2S5-based glass-ceramic is a relatively soft material, by using the electrode plate 1000 containing the Li2S-P2S5-based glass-ceramic, a battery with higher durability can be manufactured.

[0055] As the oxide solid electrolyte, for example, NASICON-type solid electrolytes represented by LiTi2(PO4)3 and its elemental substitution products, perovskite-type solid electrolytes of the (LaLi)TiO3 system, and Li 14 ZnGe4O 16 , Li4SiO4, LiGeO4, and their elemental substitution products, LISICON-type solid electrolytes represented by Li7La3Zr2O 12 and its elemental substitution products, garnet-type solid electrolytes, Li3PO4 and its N substitution products, glasses and glass-ceramics based on Li-B-O compounds such as LiBO2 and Li3BO3 and added with Li2SO4, Li2CO3, etc.

[0056] The halide solid electrolyte contains, for example, Li, M1, and X. M1 is at least one selected from metal elements and metalloid elements other than Li. X is at least one selected from F, Cl, Br, and I. Since the halide solid electrolyte has high thermal stability, the safety of the battery can be improved. Furthermore, since the halide solid electrolyte does not contain sulfur, the generation of hydrogen sulfide gas can be controlled.

[0057] In the present disclosure, the "metalloid element" is B, Si, Ge, As, Sb, and Te.

[0058] In the present disclosure, the "metal element" is all elements contained in Groups 1 to 12 of the periodic table other than hydrogen, and all elements contained in Groups 13 to 16 of the periodic table other than B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se.

[0059] That is, in the present disclosure, the "metalloid element" and the "metal element" are a group of elements that can become cations when forming inorganic compounds with halogen elements.

[0060] For example, the halide solid electrolyte can be a material represented by the following compositional formula (1).

[0061] Li α M1 β X γ Formula (1)

[0062] In the above compositional formula (1), α, β, and γ are each independently values greater than 0. γ can be 4, 6, etc.

[0063] With the above composition, the ionic conductivity of the halide solid electrolyte is increased. Accordingly, the ionic conductivity of the electrode plate 1000 can be increased. When the electrode plate 1000 is used in a battery, the cycle characteristics of the battery can be further improved.

[0064] In the above compositional formula (1), the element M1 may include Y (=yttrium). That is, the halide solid electrolyte may include Y as a metal element.

[0065] The halide solid electrolyte containing Y can be represented, for example, by the following compositional formula (2).

[0066] Li a Me b Y c X6 Formula (2)

[0067] In formula (2), a, b, and c may satisfy a + mb + 3c = 6 and c>0. The element Me is at least one selected from metal elements and metalloid elements other than Li and Y. m represents the valence of the element Me. It should be noted that when the element Me contains multiple elements, mb is the sum of the product of the composition ratio of each element and the valence of the element. For example, when Me contains element Me1 and element Me2, the composition ratio of element Me1 is b1, the valence of element Me1 is m1, the composition ratio of element Me2 is b2, and the valence of element Me2 is m2, mb is represented by m1b1 + m2b2. In the above compositional formula (2), the element X is at least one selected from F, Cl, Br, and I.

[0068] The element Me may be, for example, at least one selected from Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, Gd, and Nb.

[0069] As the halide solid electrolyte, for example, the following materials can be used. According to the following materials, the ionic conductivity of the solid electrolyte 111 is further increased, and the output characteristics of the battery can be further improved.

[0070] The halide solid electrolyte may be a material represented by the following compositional formula (A1).

[0071] Li 6-3d Y d X6 Formula (A1)

[0072] In the compositional formula (A1), the element X is at least one selected from Cl, Br, and I. In the compositional formula (A1), d satisfies 0 <d <2.

[0073] The halide solid electrolyte may be a material represented by the following compositional formula (A2).

[0074] Li3YX6 formula (A2)

[0075] In the compositional formula (A2), element X is at least one selected from Cl, Br, and I.

[0076] The halide solid electrolyte can be a material represented by the following compositional formula (A3).

[0077] Li 3-3δ Y 1+δ Cl6 formula (A3)

[0078] In the compositional formula (A3), δ satisfies 0 < δ ≤ 0.15.

[0079] The halide solid electrolyte can be a material represented by the following compositional formula (A4).

[0080] Li 3-3δ Y 1+δ Br6 formula (A4)

[0081] In the compositional formula (A4), δ satisfies 0 < δ ≤ 0.25.

[0082] The halide solid electrolyte can be a material represented by the following compositional formula (A5).

[0083] Li 3-3δ+a Y 1+δ-a Me a Cl 6-x-y Br x I y Formula (A5)

[0084] In the compositional formula (A5), element Me is at least one selected from Mg, Ca, Sr, Ba, and Zn.

[0085] Furthermore, in the above compositional formula (A5), the following are satisfied:

[0086] -1 < δ < 2,

[0087] 0 < a < 3,

[0088] 0 < (3 - 3δ + a),

[0089] 0 < (1 + δ - a),

[0090] 0 ≤ x ≤ 6,

[0091] 0 ≤ y ≤ 6, and

[0092] (x + y) ≤ 6.

[0093] The halide solid electrolyte can be a material represented by the following compositional formula (A6).

[0094] Li 3-3δY 1+δ-a Me a Cl 6-x-y Br x I y Formula (A6)

[0095] In the compositional formula (A6), the element Me is at least one selected from Al, Sc, Ga, and Bi.

[0096] Furthermore, in the above compositional formula (A6), the following are satisfied:

[0097] -1 < δ < 1,

[0098] 0 < a < 2,

[0099] 0 < (1 + δ - a),

[0100] 0 ≤ x ≤ 6,

[0101] 0 ≤ y ≤ 6, and

[0102] (x + y) ≤ 6.

[0103] The halide solid electrolyte can be a material represented by the following compositional formula (A7).

[0104] Li 3-3δ-a Y 1+δ-a Me a Cl 6-x-y Br x I y Formula (A7)

[0105] In the above compositional formula (A7), the element Me is at least one selected from Zr, Hf, and Ti.

[0106] Furthermore, in the above compositional formula (A7), the following are satisfied:

[0107] -1 < δ < 1,

[0108] 0 < a < 1.5,

[0109] 0 < (3 - 3δ - a),

[0110] 0 < (1 + δ - a),

[0111] 0 ≤ x ≤ 6,

[0112] 0 ≤ y ≤ 6, and

[0113] (x + y) ≤ 6.

[0114] The halide solid electrolyte can be a material represented by the following compositional formula (A8).

[0115] Li 3-3δ-2a Y1+δ-a Me a Cl 6-x-y Br x I y Formula (A8)

[0116] In the compositional formula (A8), the element Me is at least one selected from Ta and Nb.

[0117] Furthermore, in the above compositional formula (A8), the following conditions are satisfied:

[0118] -1 < δ < 1,

[0119] 0 < a < 1.2,

[0120] 0 < (3 - 3δ - 2a),

[0121] 0 < (1 + δ - a),

[0122] 0 ≤ x ≤ 6,

[0123] 0 ≤ y ≤ 6, and

[0124] (x + y) ≤ 6.

[0125] The halide solid electrolyte may be a compound containing Li, M2, O (oxygen), and X2. The element M2 includes, for example, at least one selected from Nb and Ta. In addition, X2 is at least one selected from F, Cl, Br, and I.

[0126] The compound containing Li, M2, X2, and O (oxygen) may be represented, for example, by the compositional formula: Li x M2O y X2 5+x-2y where x may satisfy 0.1 < x < 7.0. y may satisfy 0.4 < y < 1.9.

[0127] As the halide solid electrolyte, more specifically, for example, Li3Y(Cl, Br, I)6, Li 2.7 Y 1.1 (Cl, Br, I)6, Li2Mg(F, Cl, Br, I)4, Li2Fe(F, Cl, Br, I)4, Li(Al, Ga, In)(F, Cl, Br, I)4, Li3(Al, Ga, In)(F, Cl, Br, I)6, Li3(Ca, Y, Gd)(Cl, Br, I)6, Li 2.7 (Ti, Al)F6, Li 2.5(Ti, Al)F6, Li(Ta, Nb)O(F, Cl)4, etc. It should be noted that in this disclosure, when an element in a formula is represented as "(Al, Ga, In)", this notation means at least one element selected from the group of elements within the parentheses. That is, "(Al, Ga, In)" is synonymous with "at least one selected from Al, Ga, and In". The same applies to other elements.

[0128] As the polymer solid electrolyte, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound can have an ethylene oxide structure. The polymer compound having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further improved. As the lithium salt, LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), LiC(SO2CF3)3, etc. can be used. The lithium salt can be used alone or two or more of them can be used in combination.

[0129] As the complex hydride solid electrolyte, for example, LiBH4-LiI, LiBH4-P2S5, etc. can be used.

[0130] The shape of the solid electrolyte 111 is not particularly limited and can be needle-shaped, spherical, ellipsoidal, etc. The shape of the solid electrolyte 111 can be particulate.

[0131] When the shape of the solid electrolyte 111 is particulate (e.g., spherical), the median diameter of the solid electrolyte 111 can be 0.1 μm or more and 5 μm or less, or can be 0.5 μm or more and 3 μm or less. When the median diameter of the solid electrolyte 111 is 0.1 μm or more, the dispersibility of the electrode composition (slurry) for manufacturing the electrode plate 1000 is improved and a denser structure can be obtained. When the median diameter of the solid electrolyte 111 is 5 μm or less, the electrode plate 1000 has high surface smoothness and a denser structure can be obtained.

[0132] The so-called median diameter refers to the particle diameter at which the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is obtained by the laser diffraction scattering method. The same applies to other materials below.

[0133] The specific surface area of the solid electrolyte 111 can be 0.1 m 2 / g or more and 100 m 2 / g or less, or can be 1 m 2 / g or more and 10 m 2 / g or less. When the specific surface area of the solid electrolyte 111 is 0.1 m 2above / g and 100 m 2 When it is below / g, the dispersibility of the electrode composition (slurry) for manufacturing the electrode plate 1000 is improved, and a denser structure can be obtained. The specific surface area can be measured by the BET multipoint method using a gas adsorption amount measuring device.

[0134] The ionic conductivity of the solid electrolyte 111 can be 0.01 mS / cm 2 or more, and can also be 0.1 mS / cm 2 or more, and can also be 1 mS / cm 2 or more. When the ionic conductivity of the solid electrolyte 111 is 0.01 mS / cm 2 or more, the output characteristics of the battery can be improved.

[0135] <Active material>

[0136] The active material 112 contains a material having the property of storing and releasing metal ions (such as lithium ions). The active material 112 includes, for example, a positive electrode active material or a negative electrode active material. When the electrode plate 1000 contains the active material 112, a lithium secondary battery can be manufactured using the electrode plate 1000.

[0137] The active material 112 includes, for example, a material having the property of storing and releasing metal ions (such as lithium ions) as a positive electrode active material. Examples of the positive electrode active material include transition metal oxides, transition metal fluorides, polyanion materials, fluorinated polyanion materials, transition metal sulfides, transition metal oxysulfides, transition metal oxynitrides, and their lithium-containing compounds. Examples of the lithium-containing transition metal oxides include Li(NiCoAl)O2, Li(NiCoMn)O2, LiCoO2, etc. When using a lithium-containing transition metal oxide as the positive electrode active material, for example, the manufacturing cost of the electrode plate 1000 can be reduced, and the average discharge voltage of the battery can be increased. Li(NiCoAl)O2 means containing Ni, Co, and Al in an arbitrary ratio. Li(NiCoMn)O2 means containing Ni, Co, and Mn in an arbitrary ratio.

[0138] The median diameter of the positive electrode active material can be 0.1 μm or more and 100 μm or less, and can also be 1 μm or more and 10 μm or less. When the median diameter of the positive electrode active material is 0.1 μm or more, the active material 112 and the solid electrolyte 111 can be well dispersed in the electrode plate 1000. As a result, the charge and discharge characteristics of the battery are improved. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate in the positive electrode active material is increased. Therefore, the battery can operate at a high output.

[0139] The active material 112 contains, for example, a material having the property of storing and releasing metal ions (such as lithium ions) as the negative electrode active material. As the negative electrode active material, metal materials, carbon materials, oxides, nitrides, tin compounds, silicon compounds, etc. can be cited. The metal material can be a single metal or an alloy. As the metal material, lithium metal, lithium alloy, etc. can be cited. As the carbon material, natural graphite, coke, carbon in the middle of graphitization, carbon fiber, spherical carbon, artificial graphite, amorphous carbon, etc. can be cited. By using silicon (Si), tin (Sn), silicon compounds, tin compounds, etc., the capacity density of the battery can be improved. By using an oxide compound containing titanium (Ti) or niobium (Nb), the safety of the battery can be improved.

[0140] The median diameter of the negative electrode active material can be 0.1 μm or more and 100 μm or less, or can be 1 μm or more and 10 μm or less. When the median diameter of the negative electrode active material is 0.1 μm or more, the active material 112 and the solid electrolyte 111 can be well dispersed in the electrode plate 1000. Thereby, the charge and discharge characteristics of the battery are improved. When the median diameter of the negative electrode active material is 100 μm or less, the lithium diffusion rate in the negative electrode active material is increased. Therefore, the battery can operate at a high output.

[0141] In order to reduce the interface resistance between each active material and the solid electrolyte, the positive electrode active material and the negative electrode active material can be coated with a coating material. That is, a coating layer can be provided on the surfaces of the positive electrode active material and the negative electrode active material. The coating layer is a layer containing the coating material. As the coating material for the coating layer, a material with low electronic conductivity can be used. As the coating material for the coating layer, oxide materials, oxide solid electrolytes, halide solid electrolytes, sulfide solid electrolytes, etc. can be used. The positive electrode active material and the negative electrode active material can be coated with only one of the above-mentioned materials as the coating material. That is, for the coating layer, a coating layer formed of only one of the above-mentioned materials can be provided. Or, two or more of the above-mentioned materials can be used to provide a coating layer of two or more layers.

[0142] As the oxide material for the coating material of the coating layer, SiO2, Al2O3, TiO2, B2O3, Nb2O5, WO3, ZrO2, etc. can be cited.

[0143] As the oxide solid electrolyte for the coating material of the coating layer, the previously exemplified oxide solid electrolytes can be used. For example, Li-Nb-O compounds such as LiNbO3, Li-B-O compounds such as LiBO2, Li3BO3, Li-Al-O compounds such as LiAlO2, Li-Si-O compounds such as Li4SiO4, Li-S-O compounds such as Li2SO4, Li4Ti5O12 Li-Ti-O compounds such as etc., Li-Zr-O compounds such as Li2ZrO3, Li-Mo-O compounds such as Li2MoO3, Li-V-O compounds such as LiV2O5, Li-W-O compounds such as Li2WO4, Li-P-O compounds such as LiPO4, etc. Oxide solid electrolytes have high potential stability. Therefore, by using an oxide solid electrolyte as the coating material, the cycle characteristics of the battery can be further improved.

[0144] As the halide solid electrolyte used as the coating material for the coating layer, the halide solid electrolytes exemplified previously can be used. For example, Li-Y-Cl compounds such as LiYCl6, Li-Y-Br-Cl compounds such as LiYBr2Cl4, Li-Ta-O-Cl compounds such as LiTaOCl4, Li 2.7 Ti 0.3 Al 0.7 Li-Ti-Al-F compounds such as F6, etc. Halide solid electrolytes have high ionic conductivity and high potential stability. Therefore, by using a halide solid electrolyte as the coating material, the cycle characteristics of the battery can be further improved.

[0145] As the sulfide solid electrolyte used as the coating material for the coating layer, the sulfide solid electrolytes exemplified previously can be used. For example, Li-P-S compounds such as Li2S-P2S5, etc. Sulfide solid electrolytes have high ionic conductivity and low Young's modulus. Therefore, by using a sulfide solid electrolyte as the coating material, uniform coating can be achieved, and the cycle characteristics of the battery can be further improved.

[0146] <Second Adhesive>

[0147] As described above, the second adhesive 113 contains a styrene-based elastomer with a molar fraction of repeating units derived from styrene of 0.18 or more. According to such a configuration, a sufficient amount of aromatic rings exist in the electrode layer 110, and the interaction between the second adhesive 113 and the aromatic super engineering plastic contained in the current collector 100 is more strongly exerted, and there is a tendency for the peeling strength between the electrode layer 110 and the current collector 100 to increase. A styrene-based elastomer refers to an elastomer containing repeating units derived from styrene. A repeating unit refers to the molecular structure derived from a monomer, and is sometimes also called a structural unit. Since styrene-based elastomers are excellent in flexibility and elasticity, they are suitable as adhesives for the electrode plate 1000.

[0148] In a styrenic elastomer, the ratio of the degree of polymerization m of the repeating units derived from styrene to the degree of polymerization n of the repeating units derived from monomers other than styrene is defined as m:n. In this case, in the styrenic elastomer, the mole fraction (φ) of the repeating units derived from styrene can be calculated as φ = m / (m + n). In the styrenic elastomer, the mole fraction (φ) of the repeating units derived from styrene can be determined, for example, by proton nuclear magnetic resonance ( 1 1H-NMR) measurement.

[0149] In the styrenic elastomer, the mole fraction (φ) of the repeating units derived from styrene is 0.18 or more. Thereby, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase. The mole fraction (φ) of the styrenic elastomer can be 0.18 or more and 0.355 or less, or can be 0.18 or more and 0.3 or less. By the mole fraction (φ) of the styrenic elastomer being 0.18 or more, the strength of the electrode layer 110 can be increased. By φ of the styrenic elastomer being 0.55 or less, the flexibility of the electrode layer 110 can be increased.

[0150] The content rate of the repeating units derived from styrene in the styrenic elastomer can be 30% by mass or more. Thereby, there is a tendency for the peel strength between the electrode layer 110 and the current collector 100 to increase. The content rate of the repeating units derived from styrene in the styrenic elastomer can be 30% by mass or more and 70% by mass or less, or can be 30% by mass or more and 45% by mass or less. The content rate of the repeating units derived from styrene in the styrenic elastomer can be calculated using the mole fraction of each repeating unit contained in the styrenic elastomer and the molecular weight of each repeating unit, which can be obtained by the above-described method. Or it can be determined by a method using an ultraviolet spectrophotometer.

[0151] The styrenic elastomer can be a block copolymer including a first block composed of repeating units derived from styrene and a second block composed of repeating units derived from a conjugated diene. Examples of the conjugated diene include butadiene and isoprene. The repeating units derived from the conjugated diene can be hydrogenated. That is, the repeating units derived from the conjugated diene can have an unsaturated bond such as a carbon-carbon double bond, or can not have an unsaturated bond such as a carbon-carbon double bond. The block copolymer can have an arrangement of a triblock composed of two first blocks and one second block. The block copolymer can be an ABA-type triblock copolymer. In this triblock copolymer, the A block corresponds to the first block, and the B block corresponds to the second block. The first block functions as a hard segment, for example. The second block functions as a soft segment, for example.

[0152] Examples of the styrenic elastomer include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene rubber (SBR), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-butadiene rubber (HSBR), etc. The second binder 113 may contain SBR or SEBS as the styrenic elastomer. As the second binder 113, a mixture containing two or more selected from the above may be used. Since the styrenic elastomer is excellent in flexibility and elasticity, it is suitable as the binder for the electrode layer 110.

[0153] The styrenic elastomer may be a styrenic triblock copolymer. Examples of the styrenic triblock copolymer include styrene-ethylene / butylene-styrene block copolymer (SEBS), styrene-ethylene / propylene-styrene block copolymer (SEPS), styrene-ethylene / ethylene / propylene-styrene block copolymer (SEEPS), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), etc. These styrenic triblock copolymers are sometimes referred to as styrenic thermoplastic elastomers. These styrenic triblock copolymers have the following tendency: they are soft and have high strength.

[0154] The styrenic elastomer may contain styrene-ethylene / butylene-styrene block copolymer (SEBS). Since SEBS is excellent in flexibility and elasticity and has excellent filling properties during hot compression, it is particularly suitable as the binder for the electrode layer 110.

[0155] Styrene-based elastomers may contain modifying groups. The so-called modifying groups refer to functional groups that chemically modify all of the repeating units contained in the polymer chain, a part of the repeating units contained in the polymer chain, or the terminal portion of the polymer chain. Modifying groups can be introduced into the polymer chain through substitution reactions, addition reactions, etc. Modifying groups include, for example, elements such as O, N, S, F, Cl, Br, F with relatively high electronegativity, and Si, Sn, P with relatively low electronegativity. By using modifying groups containing such elements, polarity can be imparted to the polymer. Examples of modifying groups include carboxyl groups, acid anhydride groups, acyl groups, hydroxyl groups, sulfo groups, thioalkyl groups, phosphoric acid groups, phosphonic acid groups, isocyanate groups, epoxy groups, silyl groups, amino groups, nitrile groups, nitro groups, etc. A specific example of the acid anhydride group is the maleic anhydride group. As the modifying group, it can be a functional group that can be introduced by reacting a modifier generated from the following compounds. Examples of the compounds used as modifiers include epoxy compounds, ether compounds, ester compounds, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing amino groups, vinyl compounds containing amino groups, epoxy compounds containing amino groups, mercapto derivatives, thiocarbonyl compounds, silicon halide compounds, epoxy silicon compounds, vinylated silicon compounds, alkoxysilane compounds, alkoxysilane compounds containing amino groups, tin halide compounds, organotin carboxylate compounds, phosphite compounds, phosphine compounds, etc. In the second adhesive 113, when the styrene-based elastomer contains the above-mentioned modifying groups, the peel strength between the electrode layer 110 and the current collector 100 can be improved through the interaction with the current collector 100.

[0156] Styrene-based elastomers may contain modifying groups having nitrogen atoms. The so-called modifying groups having nitrogen atoms are nitrogen-containing functional groups, and examples thereof include amino groups such as amine compounds. The position of the modifying group can be at the polymer chain end. The styrene-based elastomer can be, for example, a terminal amine-modified styrene-based elastomer. The styrene-based elastomer can be, for example, a styrene-based elastomer having a star polymer structure centered on a nitrogen-containing alkoxysilane substituent and having nitrogen atoms at at least one end of the polymer chain.

[0157] The weight-average molecular weight (M w)It can be 200,000 or more. The weight-average molecular weight of the styrene-based elastomer can be 300,000 or more, can also be 500,000 or more, can also be 800,000 or more, and can also be 1,000,000 or more. The upper limit value of the weight-average molecular weight is, for example, 1,500,000. By the weight-average molecular weight of the styrene-based elastomer being 200,000 or more, the particles of the solid electrolyte 111 and the active material 112 can be bonded with sufficient adhesive strength. By the weight-average molecular weight of the styrene-based elastomer being 1,500,000 or less, the ion conduction between the particles of the solid electrolyte 111 is not easily hindered by the second binder 113, and the output characteristics of the battery can be improved. The weight-average molecular weight of the styrene-based elastomer can be determined, for example, by gel permeation chromatography (GPC) measurement using polystyrene as a standard sample. In other words, the weight-average molecular weight is a value converted to polystyrene. In GPC measurement, chloroform can be used as an eluent. When two or more peaks are observed in the graph obtained by GPC measurement, the weight-average molecular weight calculated from the entire peak range including each peak can be regarded as the weight-average molecular weight of the styrene-based elastomer.

[0158] The second binder 113 may contain a binder other than the styrene-based elastomer. Alternatively, the second binder 113 may be a styrene-based elastomer. In other words, the second binder 113 may contain only the styrene-based elastomer.

[0159] In order to improve processability, the styrene-based elastomer may be an oil-extended polymer compounded with processing oil or the like. As the processing oil, for example, aromatic oil, paraffin oil, naphthenic oil, vegetable oil, oil with a low content of polycyclic aromatic compounds (low PCA oil), etc. can be cited. As the processing oil, low PCA oil can be used. As the low PCA oil, for example, mildly extracted solvate (MES), oil after treating aromatic extracts from distillate oil (TDAE), aromatic special extracts from residual oil (SRAE), heavy naphthenic oil, etc. can be cited. The ratio of the mass of the processing oil to the mass of the styrene-based elastomer is not particularly limited, and is, for example, 10% by mass or more and 100% by mass or less. By the second binder 113 containing the processing oil, the processing oil acts as a lubricant, and the filling property of the electrode layer 110 can be improved.

[0160] The ratio of the mass of the processing oil to the mass of the styrene-based elastomer can be 1% by mass or less. By making the ratio of the mass of the processing oil to the mass of the styrene-based elastomer 1% by mass or less, the reaction between the processing oil and the solid electrolyte can be suppressed, and the cycle characteristics of the battery can be improved. When the styrene-based elastomer is an oil-extended polymer, by dissolving the styrene-based elastomer in tetrahydrofuran (THF) and then performing washing by reprecipitation in ethanol and reprecipitation in acetone, the oil contained in the styrene-based elastomer can be removed.

[0161] <Electrode layer>

[0162] The electrode layer 110 includes a second binder 113. The electrode layer 110 may further include a solid electrolyte 111, may include an active material 112, or may include both. According to this configuration, while maintaining sufficient strength of the electrode layer 110, the ionic conductivity inside the electrode layer 110 is improved, and the battery can operate at a high output.

[0163] The median diameter of the solid electrolyte 111 contained in the electrode layer 110 may be smaller than the median diameter of the active material 112. Thus, the solid electrolyte 111 and the active material 112 can be well dispersed.

[0164] In the electrode layer 110, for the volume ratio "v1: 100 - v1" of the active material 112 and the solid electrolyte 111, 30 ≤ v1 ≤ 95 can be satisfied. v1 represents the volume ratio of the active material 112 when the total volume of the active material 112 and the solid electrolyte 111 contained in the electrode layer 110 is set to 100. When 30 ≤ v1 is satisfied, it is easy to ensure sufficient energy density for the battery. When v1 ≤ 95 is satisfied, the battery can operate more easily at a high output.

[0165] The thickness of the electrode layer 110 may be 10 μm or more and 500 μm or less. When the thickness of the electrode layer 110 is 10 μm or more, it is easy to ensure sufficient energy density for the battery. When the thickness of the electrode layer 110 is 500 μm or less, the battery can operate more easily at a high output.

[0166] In the electrode layer 110, the ratio of the second binder 113 to the solid electrolyte 111 may be 0.1 mass% or more and 10 mass% or less, may be 0.5 mass% or more and 8 mass% or less, or may be 1 mass% or more and 5 mass% or less. When the ratio of the second binder 113 to the solid electrolyte 111 is 0.1 mass% or more, there is a tendency to bond more particles of the solid electrolyte 111 using the second binder 113. Thus, the film strength of the electrode layer 110 can be improved. When the ratio of the second binder 113 to the solid electrolyte 111 is 10 mass% or less, in the electrode layer 110, there is a tendency to improve the contact between the particles of the solid electrolyte 111. Thus, the ionic conductivity of the electrode layer 110 can be improved.

[0167] In the electrode layer 110, the ratio of the second binder 113 to the active material 112 may be 0.03% by mass or more and 4% by mass or less, may also be 0.15% by mass or more and 2% by mass or less, and may also be 0.3% by mass or more and 1% by mass or less. When the ratio of the second binder 113 to the active material 112 is 0.03% by mass or more, there is a tendency to bond more particles of the active material 112 using the second binder 113. Thereby, the film strength of the electrode layer 110 can be improved. When the ratio of the second binder 113 to the active material 112 is 4% by mass or less, in the electrode layer 110, there is a tendency for the contact between the particles of the active material 112 to be improved. Thereby, the output characteristics of the battery can be improved.

[0168] For the purpose of improving electron conductivity, the electrode layer 110 may further contain a conductive additive. As the conductive additive, for example, graphite-based materials such as natural graphite and artificial graphite, carbon black-based materials such as acetylene black and Ketjen black, conductive fiber-based materials such as carbon fiber and metal fiber, conductive powder-based materials such as carbon fluoride and aluminum, conductive whisker-based materials such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymers such as polyaniline, polypyrrole, and polythiophene can be cited. If a carbon material is used as the conductive additive, cost reduction can be achieved.

[0169] For the purpose of improving the dispersibility of the solid electrolyte 111 and the active material 112, the electrode layer 110 may contain a dispersant. The dispersant may be a low molecular weight dispersant or a high molecular weight dispersant. As the dispersant, for example, commercially available dispersants, wetting agents, or surfactants can be used.

[0170] In the electrode layer 110, the dispersant may contain an amine compound. The amine compound is suitable for improving the dispersibility of the solid electrolyte 111. As the amine compound, for example, aliphatic amines such as methylamine and dimethylamine, aromatic amines such as aniline, and heterocyclic amines such as imidazole and imidazoline can be cited.

[0171] In the electrode layer 110, the dispersant may contain imidazoline or an imidazoline derivative. Imidazoline or an imidazoline derivative is more suitable for improving the dispersibility of the solid electrolyte 111. As the imidazoline derivative, for example, 1-hydroxyethyl-2-alkenyl imidazoline can be cited.

[0172] In the electrode layer 110, the ratio of the mass of the dispersant to the mass of the solid electrolyte 111 is not particularly limited. For example, it is 0.001% by mass or more and 10% by mass or less, and may also be 0.01% by mass or more and 1.0% by mass or less. When the ratio of the mass of the dispersant is 0.001% by mass or more, the dispersibility of the solid electrolyte 111 can be improved in the electrode layer 110. When the ratio of the mass of the dispersant is 10% by mass or less, a decrease in the ionic conductivity of the solid electrolyte 111 can be suppressed.

[0173] [Method for manufacturing electrode plate]

[0174] The electrode plate 1000 can be manufactured, for example, by the following method. First, an electrode composition containing a solid electrolyte 111, an active material 112, and a second binder 113 for forming the electrode layer 110 is prepared. As the electrode composition, a slurry in which the solid electrolyte 111, the active material 112, and the second binder 113 are dispersed in a solvent can be used. As the solvent, a solvent that does not react with the solid electrolyte 111, such as an aromatic hydrocarbon-based solvent like tetralin, can be used. Next, the electrode composition is coated on the coating layer 102 of the current collector 100. As methods for coating the electrode composition, an extrusion die coating method, a gravure coating method, a doctor blade method, a rod coating method, a spraying method, an electrostatic coating method, etc. can be cited. By drying the obtained coating film, the electrode layer 110 is formed, and the electrode plate 1000 can be obtained. There is no particular limitation on the drying method of the coating film. For example, the coating film can be dried by heating the coating film at a set temperature of 80°C or higher and 150°C or lower using warm air / hot air drying. It should be noted that the method of coating the electrode composition on the coating layer 102 to form the electrode layer 110 is sometimes referred to as a wet coating method.

[0175] [Method for measuring peel strength of electrode plate]

[0176] The peel strength between the electrode layer 110 and the current collector 100 can be measured by the following method in a drying chamber with a dew point of -50°C or lower using a universal material testing machine (manufactured by A&D Company, RTH-1310). First, the electrode plate 1000 cut to a width of 15 mm is bonded to a double-sided tape for test plate. Specifically, the electrode layer 110 of the electrode plate 1000 is bonded to the test plate via the double-sided tape. Next, using a testing machine equipped with a jig for a 90° peel test of the tape, the electrode layer 110 is peeled from the current collector 100 at a peel angle of 90° and a peel speed of 5 mm / min. Then, after the start of measurement, the measured values for the length from the initial 5 mm to 12 mm peeled from the current collector 100 are not used, and then, for the electrode layer 110 with a length of 5 mm peeled from the current collector 100, the continuously recorded measured values (unit: N) are recorded. The average value (Av) obtained by dividing the measured value by the width of the electrode plate 1000 can be regarded as the peel strength between the electrode layer 110 and the current collector 100 in the electrode plate 1000 (unit: N / m).

[0177] (Embodiment 2)

[0178] Figure 2 It is a cross-sectional view of the battery 2000 according to Embodiment 2. The battery 2000 includes a negative electrode 201, a positive electrode 203, and an electrolyte layer 202.

[0179] At least one selected from the negative electrode 201 and the positive electrode 203 includes the electrode plate 1000 in Embodiment 1. That is, at least one selected from the negative electrode 201 and the positive electrode 203 includes the electrode layer 110 and the current collector 100.

[0180] The electrolyte layer 202 is located between the negative electrode 201 and the positive electrode 203.

[0181] Since the peeling strength between the electrode layer 110 and the current collector 100 is high, the battery 2000 using the electrode plate 1000 having such an electrode layer 110 and current collector 100 has excellent cycle characteristics. In addition, the output characteristics of the battery 2000 can also be improved.

[0182] As Figure 2 shown, in the battery 2000, the negative electrode 201 may be the electrode plate 1000 in Embodiment 1. In this case, the negative electrode 201 includes the electrode layer 110 and the current collector 100 described in Embodiment 1. Hereinafter, the battery 2000 in which the negative electrode 201 is the electrode plate 1000 will be described. However, the battery 2000 is not limited to the following form. In the battery 2000, the positive electrode 203 may be the electrode plate 1000 in the above-described Embodiment 1.

[0183] According to the above configuration, the output characteristics of the battery 2000 can be further improved.

[0184] The electrolyte layer 202 is a layer containing an electrolyte material. As the electrolyte material, for example, a solid electrolyte can be cited. That is, the electrolyte layer 202 may be a solid electrolyte layer. As the solid electrolyte contained in the electrolyte layer 202, the solid electrolytes exemplified as the solid electrolyte 111 can be used. For example, a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte, a polymer solid electrolyte, a complex hydride solid electrolyte, etc. can be used.

[0185] The electrolyte layer 202 may contain a solid electrolyte as a main component. The electrolyte layer 202 may contain a solid electrolyte in a mass ratio of 70% or more (70 mass% or more) with respect to the whole of the electrolyte layer 202.

[0186] According to the above configuration, the charge-discharge characteristics of the battery 2000 can be improved.

[0187] The electrolyte layer 202 contains a solid electrolyte as a main component, and may further contain inevitable impurities, or starting materials, by-products, and decomposition products used in synthesizing the solid electrolyte.

[0188] The electrolyte layer 202 may contain a solid electrolyte in a mass ratio of 100% (100 mass%) with respect to the whole of the electrolyte layer 202 except for inevitably mixed impurities.

[0189] According to the above configuration, the charge-discharge characteristics of the battery 2000 can be further improved.

[0190] The electrolyte layer 202 may contain two or more of the materials listed as solid electrolytes. For example, the electrolyte layer 202 may contain a halide solid electrolyte and a sulfide solid electrolyte.

[0191] The thickness of the electrolyte layer 202 may be 1 μm or more and 300 μm or less. When the thickness of the electrolyte layer 202 is 1 μm or more, the possibility of short circuit between the negative electrode 201 and the positive electrode 203 is reduced. When the thickness of the electrolyte layer 202 is 300 μm or less, the battery 2000 can easily operate at high output. That is, if the thickness of the electrolyte layer 202 is appropriately adjusted, the safety of the battery 2000 can be sufficiently ensured, and the battery 2000 can operate at high output.

[0192] There is no particular limitation on the shape of the solid electrolyte contained in the battery 2000. The shape of the solid electrolyte may be needle-like, spherical, ellipsoidal, etc. The shape of the solid electrolyte may be particulate.

[0193] The positive electrode 203 may contain an electrolyte material, for example, it may contain a solid electrolyte. As the solid electrolyte, the solid electrolytes exemplified as the materials constituting the electrolyte layer 202 can be used. According to the above configuration, the ionic conductivity (for example, lithium ion conductivity) inside the positive electrode 203 is improved, and the battery 2000 can operate at high output.

[0194] The positive electrode 203 contains, for example, a material having the property of storing and releasing metal ions (for example, lithium ions) as a positive electrode active material. As the positive electrode active material, the materials exemplified in the above Embodiment 1 can be used.

[0195] The median diameter of the positive electrode active material may be 0.1 μm or more and 100 μm or less. When the median diameter of the positive electrode active material is 0.1 μm or more, in the positive electrode 203, the positive electrode active material and the solid electrolyte can be well dispersed. Thereby, the charge-discharge characteristics of the battery 2000 are improved. When the median diameter of the positive electrode active material is 100 μm or less, the lithium diffusion rate inside the positive electrode active material is increased. Therefore, the battery 2000 can operate at high output.

[0196] The median diameter of the positive electrode active material may be larger than the median diameter of the solid electrolyte. Thereby, the solid electrolyte and the positive electrode active material can be well dispersed.

[0197] In the positive electrode 203, for the volume ratio "v2: 100 - v2" of the positive electrode active material to the solid electrolyte, 30 ≤ v2 ≤ 95 can be satisfied. v2 represents the volume ratio of the positive electrode active material when the total volume of the positive electrode active material and the solid electrolyte contained in the positive electrode 203 is set to 100. When 30 ≤ v2 is satisfied, it is easy to ensure sufficient energy density for the battery 2000. When v2 ≤ 95 is satisfied, the battery 2000 can operate more easily at high output.

[0198] The thickness of the positive electrode 203 can be 10 μm or more and 500 μm or less. When the thickness of the positive electrode 203 is 10 μm or more, it is easy to ensure sufficient energy density for the battery 2000. When the thickness of the positive electrode 203 is 500 μm or less, the battery 2000 can operate more easily at high output.

[0199] In order to reduce the interfacial resistance with the solid electrolyte, the positive electrode active material can be coated with a coating material. As the coating material, a material with low electronic conductivity can be used. As the coating material, an oxide material, an oxide solid electrolyte, etc. can be used. As the coating material, the materials exemplified in Embodiment 1 can be used.

[0200] For the purpose of improving the adhesion between particles, at least one selected from the electrolyte layer 202 and the positive electrode 203 may contain a binder. As the binder, the materials exemplified in Embodiment 1 can be used. The binder can be used alone or two or more can be used in combination.

[0201] As the binder, from the viewpoint of excellent adhesiveness, an elastomer can be used. An elastomer refers to a polymer having elasticity. The elastomer used as the binder can be a thermoplastic elastomer or a thermosetting elastomer. The binder can contain a thermoplastic elastomer. As the elastomer, the materials exemplified in Embodiment 1 can be used. When the binder contains an elastomer, for example, through thermal compression during the manufacture of the battery 2000, high filling can be achieved for the electrolyte layer 202 or the positive electrode 203.

[0202] For the purpose of facilitating the transfer of lithium ions and improving the output characteristics of the battery 2000, at least one selected from the electrode layer 110 of the negative electrode 201, the electrolyte layer 202, and the positive electrode 203 may contain a non-aqueous electrolyte, a gel electrolyte, or an ionic liquid.

[0203] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent. As the non-aqueous solvent, a cyclic carbonate solvent, a linear carbonate solvent, a cyclic ether solvent, a linear ether solvent, a cyclic ester solvent, a linear ester solvent, a fluorine solvent, etc. can be used. As the cyclic carbonate solvent, ethylene carbonate, propylene carbonate, butylene carbonate, etc. can be cited. As the linear carbonate solvent, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, etc. can be cited. As the cyclic ether solvent, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, etc. can be cited. As the linear ether solvent, 1,2-dimethoxyethane, 1,2-diethoxyethane, etc. can be cited. As the cyclic ester solvent, γ-butyrolactone, etc. can be cited. As the linear ester solvent, methyl acetate, etc. can be cited. As the fluorine solvent, fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoromethyl ethyl carbonate, difluoromethyl carbonate, etc. can be cited. As the non-aqueous solvent, one non-aqueous solvent selected from the above can be used alone, or a mixture of two or more non-aqueous solvents selected from the above can be used.

[0204] In the non-aqueous electrolyte, at least one fluorine solvent selected from fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoromethyl ethyl carbonate, and difluoromethyl carbonate can be contained.

[0205] As the lithium salt, LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), LiC(SO2CF3)3, etc. can be cited. As the lithium salt, one lithium salt selected from the above can be used alone, or a mixture of two or more lithium salts selected from the above can be used. The concentration of the lithium salt in the non-aqueous electrolyte can be 0.5 mol / L or more and 2 mol / L or less.

[0206] As the gel electrolyte, a material containing a non-aqueous electrolyte in a polymer material can be used. As the polymer material, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a polymer having an ethylene oxide bond, etc. can be cited.

[0207] The cation constituting the ionic liquid can be an aliphatic chain-like quaternary cation such as tetraalkylammonium or tetraalkylphosphonium, an aliphatic cyclic ammonium such as pyrrolidinium, morpholinium, imidazolinium, tetrahydropyrimidinium, piperazinium, or piperidinium, or a nitrogen-containing heterocyclic aromatic cation such as pyridinium or imidazolium. The anion constituting the ionic liquid can be PF6 - , BF4 - , SbF6 - , AsF6 - , SO3CF3 - , N(SO2F)2- , N(SO2CF3)2 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - , C(SO2CF3)3 - etc. The ionic liquid may contain a lithium salt.

[0208] For the purpose of improving electron conductivity, at least one of the electrode layer 110 selected from the negative electrode 201 and the positive electrode 203 may contain a conductive additive. As the conductive additive, the materials exemplified in Embodiment 1 can be used.

[0209] For the purpose of improving the dispersibility of the solid electrolyte and the active material, at least one of the electrode layer 110 selected from the negative electrode 201 and the positive electrode 203 may contain a dispersant. As the dispersant, the materials exemplified in Embodiment 1 can be used.

[0210] As the shape of the battery 2000, coin type, cylindrical type, square type, sheet type, button type, flat type, laminated type, etc. can be cited.

[0211] The battery 2000 can be manufactured, for example, by the following method. First, the current collector 100, the material for forming the electrode layer 110, the material for forming the electrolyte layer 202, the material for forming the positive electrode 203, and the current collector for the positive electrode 203 are prepared respectively. Using them, a laminate in which the negative electrode 201, the electrolyte layer 202, and the positive electrode 203 are arranged in sequence is fabricated by a known method. Thereby, the battery 2000 can be manufactured.

[0212] Figure 3A cross-sectional view of the battery 2001 according to the modified example. The battery 2001 may be a laminate of a plurality of batteries 2000. The battery 2001 can be manufactured by the following method. A negative electrode (first negative electrode 211), a first electrolyte layer 212, and a first positive electrode 213 are laminated on a current collector 100 formed by sequentially disposing coating layers 102 on both sides of a substrate 101. On the other hand, an electrode layer 110 (second negative electrode 221), a second electrolyte layer 222, and a second positive electrode 223 are sequentially disposed on the surface of the current collector 100 opposite to the surface on which the first negative electrode 211 is laminated. Thus, a laminate in which the first positive electrode 213, the first electrolyte layer 212, the first negative electrode 211, the current collector 100, the second negative electrode 221, the second electrolyte layer 222, and the second positive electrode 223 are sequentially disposed is obtained. The battery 2001 can be manufactured by compression molding of this laminate using a press at a high temperature, for example, at a temperature of 120 °C or higher and 195 °C or lower. According to such a method, it is possible to manufacture a laminate of two batteries 2000 while suppressing warping of the battery, and it is possible to manufacture a high-output battery 2001 with higher efficiency. It should be noted that in the manufacture of the battery 2001, there is no particular limitation on the order in which the respective members are laminated. For example, by laminating the first electrolyte layer 212, the second electrolyte layer 222, the first positive electrode 213, and the second positive electrode 223 in this order after disposing the first negative electrode 211 and the second negative electrode 221 on the current collector 100, a laminate of two batteries 2000 can be manufactured. Further, by separately preparing a plurality of batteries 2001 and a current collector for the positive electrode and alternately laminating the battery 2001 and the positive electrode current collector, a laminate of the battery 2000 can be manufactured. By adopting such a method, it is possible to laminate the battery 2000 with high efficiency.

[0213] (Other embodiments)

[0214] (Supplementary note)

[0215] According to the description of the above embodiments, the following technology is disclosed.

[0216] (Technology 1)

[0217] An electrode plate, comprising: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing conductive carbon and a first binder, the electrode layer containing a second binder, the first binder containing an aromatic super engineering plastic, and the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.18 or more.

[0218] According to such a configuration, the peel strength between the electrode layer and the current collector can be improved.

[0219] (Technology 2)

[0220] The electrode plate according to Technique 1, wherein the aromatic super engineering plastic contains polyimide. Polyimide has a tendency to exhibit higher heat resistance. Therefore, even when the member including the current collector is compressed at a high temperature, the coating layer is not easily adhered to production equipment such as a press. As a result, the productivity of the electrochemical device is improved.

[0221] (Technique 3)

[0222] The electrode plate according to Technique 1 or 2, wherein the substrate contains aluminum or an aluminum alloy. With such a configuration, not only can the peel strength between the electrode layer and the current collector be improved, but also the mass energy density of the electrochemical device can be improved.

[0223] (Technique 4)

[0224] The electrode plate according to any one of Techniques 1 to 3, wherein the electrode layer further contains a solid electrolyte. The electrode plate of the present disclosure is suitable for an electrochemical device, particularly a battery, that includes a solid electrolyte in the electrode layer.

[0225] (Technique 5)

[0226] The electrode plate according to Technique 4, wherein the solid electrolyte contains a sulfide solid electrolyte. Since the sulfide solid electrolyte has more excellent ionic conductivity and moldability, it is particularly suitable as the solid electrolyte of the electrode layer.

[0227] (Technique 6)

[0228] A battery including: a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode, wherein at least one selected from the positive electrode and the negative electrode is the electrode plate according to any one of Techniques 1 to 5.

[0229] Since the peel strength between the electrode layer and the current collector is high, the cycle characteristics of the battery using the electrode plate having such an electrode layer and current collector are excellent.

[0230] Examples

[0231] Hereinafter, the details of the present disclosure will be described using examples and comparative examples. It should be noted that the current collector, electrode plate, and battery of the present disclosure are not limited to the following examples.

[0232] <Example 1-1>

[0233] [Production of Current Collector]

[0234] A coating was prepared by kneading electrically conductive carbon, a first binder, and a solvent. As the electrically conductive carbon, carbon black and graphite were used. As the first binder, soluble polyimide, which is an aromatic super engineering plastic, was used. Next, the coating was applied to one side of an aluminum alloy foil (A3003 foil, thickness: 15 μm) to form a coating film. The coating film was dried at 165°C to form a coating layer. Further, the coating was applied to the other side of the aluminum alloy foil to form a coating film. The coating film was dried at 165°C to form a coating layer. Thus, a current collector having coating layers on both sides was produced. In the current collector of Example 1-1, the mass per unit area of the coating layer was 1.3 g / m 2 .

[0235] [Solvent]

[0236] In all of the following steps, as the solvent, a commercially available dehydrated solvent or a solvent dehydrated by nitrogen bubbling was used. The water content in the solvent was 10 mass ppm or less.

[0237] [Preparation of Second Binder Solution]

[0238] A second binder solution was prepared by adding a solvent to the second binder to dissolve or disperse the second binder in the solvent. The concentration of the binder in the second binder solution was 5 mass% or more and 10 mass% or less.

[0239] As the solvent for the second binder solution, tetralin was used. As the styrene-based elastomer constituting the second binder, a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei Corporation, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON Corporation, G1633) in a mass ratio of 1:4 was used. "Tuftec" is a registered trademark of Asahi Kasei Corporation.

[0240] [Determination of Mole Fraction of Repeating Unit Derived from Styrene]

[0241] The mole fraction of the repeating unit derived from styrene in the styrene-based elastomer was determined by the following method. First, for the measurement sample containing the styrene-based elastomer, proton nuclear magnetic resonance ( 1 1H-NMR) measurement was performed using a nuclear magnetic resonance apparatus (manufactured by Bruker Corporation, AVANCE500). As the measurement sample, a product obtained by dissolving the styrene-based elastomer in CDCl3 was used. CDCl3 contained 0.05% of tetramethylsilane (TMS). 11H-NMR measurement was carried out under the conditions of a resonance frequency of 500 MHz and a measurement temperature of 23 °C. The integral values of the peaks from the styrene backbone and the integral values of the peaks from other backbones other than the styrene backbone were determined from the obtained NMR spectrum. Using the determined integral values, the mole fraction of the repeating units from styrene in the styrene-based elastomer was determined.

[0242] [Measurement of weight-average molecular weight]

[0243] The weight-average molecular weight (M w ) of the styrene-based elastomer constituting the second binder was measured by gel permeation chromatography (GPC) using a high-speed GPC device (manufactured by Tosoh Corporation, HLC-832-GPC). As the measurement sample, a product obtained by dissolving the styrene-based elastomer in chloroform and filtering it through a filter with a pore size of 0.2 μm was used. As the column, 2 Super HM-H columns manufactured by Tosoh Corporation were used. A differential refractometer was used in the GPC measurement. The GPC measurement was carried out under the conditions of a flow rate of 0.6 mL / min and a column temperature of 40 °C. As the standard sample, monodisperse polystyrene (manufactured by Tosoh Corporation) was used. By the GPC measurement, the weight-average molecular weight (M w ) of the styrene-based elastomer was determined.

[0244] [Fabrication of electrode plate]

[0245] In an argon glove box with a dew point of -60 °C or lower, tetralin and a second binder solution were added to a Li2S-P2S5-based glass-ceramic (hereinafter referred to as "LPS"). The mixing of these materials was carried out at a mass ratio of LPS:second binder = 100:3 and adjusted so that the solid content concentration (NV) became 45.0. Next, for the obtained mixture, a homogenizer (manufactured by As one Corporation, HG-200) and a stirrer (manufactured by As one Corporation, K-20S) were used to perform dispersion and kneading with high shear to fabricate a slurry. Next, the slurry was coated on the coating layer of the current collector, and the obtained coating film was dried at 100 °C for 1 hour in a vacuum atmosphere to fabricate the electrode plate of Example 1-1.

[0246] <Example 1-2>

[0247] Except that a solution-polymerized styrene-butadiene rubber (oil-extended modified SBR, manufactured by Asahi Kasei Corporation, TUFDENE E680, containing an operation oil with M w = about 800) was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 45.5, the electrode plate of Example 1-2 was fabricated in the same manner as in Example 1-1. "TUFDENE" is a registered trademark of Asahi Kasei Corporation.

[0248] <Examples 1 - 3>

[0249] Except that solution - polymerized styrene - butadiene rubber (oil - extended modified SBR, manufactured by Asahi Kasei Corporation, TUFDENE F3440, containing M w = about 600 processing oil) was used as the styrenic elastomer constituting the second binder, the electrode plates of Examples 1 - 3 were fabricated in the same manner as in Examples 1 - 2.

[0250] <Examples 1 - 4>

[0251] Except that solution - polymerized styrene - butadiene rubber (oil - extended modified SBR, manufactured by Asahi Kasei Corporation, TUFDENE F3520, containing M w = about 600 processing oil) was used as the styrenic elastomer constituting the second binder, the electrode plates of Examples 1 - 4 were fabricated in the same manner as in Examples 1 - 2.

[0252] <Examples 1 - 5>

[0253] Except that solution - polymerized styrene - butadiene rubber (oil - extended modified SBR, manufactured by Asahi Kasei Corporation, TUFDENE XF354, containing M w = about 500 processing oil) and the solid - content concentration (NV) of the slurry was adjusted to 43.0, the electrode plates of Examples 1 - 5 were fabricated in the same manner as in Examples 1 - 1.

[0254] <Comparative Example 1 - 1>

[0255] Except that polyvinylidene fluoride was used as the first binder, the electrode plates of Comparative Example 1 - 1 were fabricated in the same manner as in Examples 1 - 1. In the current collector of Comparative Example 1 - 1, the coating weight of the material constituting the coating layer was 0.94 g / m 2 .

[0256] <Comparative Example 1 - 2>

[0257] Except that polyvinylidene fluoride was used as the first binder, the electrode plates of Comparative Example 1 - 2 were fabricated in the same manner as in Examples 1 - 2.

[0258] <Comparative Example 1 - 3>

[0259] Except that polyvinylidene fluoride was used as the first binder, the electrode plates of Comparative Example 1 - 3 were fabricated in the same manner as in Examples 1 - 3.

[0260] <Comparative Example 1 - 4>

[0261] The electrode plates of Comparative Examples 1-4 were fabricated in the same manner as in Examples 1-4, except that polyvinylidene fluoride was used as the first binder.

[0262] <Comparative Examples 1-5>

[0263] The electrode plates of Comparative Example 1-5 were fabricated in the same manner as in Examples 1-5, except that polyvinylidene fluoride was used as the first binder.

[0264] <Comparative Example 1-6>

[0265] The electrode plates of Comparative Example 1-6 were fabricated in the same manner as in Example 1-1, except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei Corporation, Asaprene Y031) was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 47.0. "Asaprene" is a registered trademark of Asahi Kasei Corporation.

[0266] <Comparative Example 1-7>

[0267] The electrode plates of Comparative Example 1-7 were fabricated in the same manner as in Comparative Example 1-6, except that polyvinylidene fluoride was used as the first binder.

[0268] <Comparative Example 1-8>

[0269] The electrode plates of Comparative Example 1-8 were fabricated in the same manner as in Example 1-1, except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei Corporation, Asaprene XB120) was used as the styrene-based elastomer constituting the second binder, and the solid content concentration (NV) of the slurry was adjusted to 43.0.

[0270] <Comparative Example 1-9>

[0271] The electrode plates of Comparative Example 1-9 were fabricated in the same manner as in Comparative Example 1-8, except that polyvinylidene fluoride was used as the first binder.

[0272] [Peel Test]

[0273] Using the method described previously, the peel strength of the electrode plates of the examples and comparative examples was measured. The results are shown in Table 1. For the measurement of the peel strength, each electrode plate was subjected to three tests. The "peel strength" shown in Table 1 is the average of the values obtained from the three measurements.

[0274] Table 1

[0275]

[0276] In Comparative Examples 1-1 to 1-5, the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer was 0.19 or 0.24. However, it is considered that since the first binder of the coating layer of the current collector is polyvinylidene fluoride, the interaction between the current collector and the electrode layer was not sufficiently exerted. As a result, the peel strength of the electrode plates of Comparative Examples 1-1 to 1-5 was low.

[0277] In Comparative Examples 1-6 and 1-8, the first binder of the current collector was polyimide which is an aromatic super engineering plastic. However, the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer was as low as 0.16 or 0.09. Therefore, it is considered that the interaction between the current collector and the electrode layer was not sufficiently exerted. As a result, the peel strength of the electrode plates of Comparative Examples 1-6 and 1-8 was low.

[0278] In Comparative Examples 1-7 and 1-9, the first binder of the current collector was polyvinylidene fluoride, and the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer was also low. Therefore, the peel strength of the electrode plates of Comparative Examples 1-7 and 1-9 was low.

[0279] From the results shown in Table 1, it can be seen that the type of the first binder in the coating layer of the current collector and the molar fraction of the repeating unit derived from styrene in the second binder of the electrode layer are related to the peel strength. In the electrode plates of Examples 1-1 to 1-4 in which an aromatic super engineering plastic was used as the first binder and a styrene-based elastomer having a molar fraction of the repeating unit derived from styrene of 0.18 or more was used as the second binder, the peel strength between the electrode layer and the current collector showed a high value.

[0280] <Example 2-1>

[0281] [Fabrication of Electrode Plate]

[0282] In an argon glove box with a dew point below -60°C, 250 g of LTO was weighed, and 136 g of tetralin and 15.0 g of a dispersant solution containing a dispersant at a concentration of 5% by mass were added to prepare a mixed solution. As the dispersant, 1-hydroxyethyl-2-vinylimidazoline (manufactured by BYK, DISPERBYK-109) was used. As the solvent for the dispersant solution, tetralin was used. For this mixed solution, a bench-top digital ultrasonic homogenizer (manufactured by BRANSON, SONIFIER SFX550) was used to perform dispersion and kneading. Then, 43.4 g of a second binder solution containing a second binder at a concentration of 5% by mass, 2.75 g of vapor-grown carbon fiber (manufactured by Showa Denko, VGCF-H), and 84.0 g of LPS were added to the mixed solution, and dispersion and kneading were performed to prepare a slurry. As the second binder, a mixture containing a hydrogenated styrene-based thermoplastic elastomer (modified SEBS, manufactured by Asahi Kasei, Tuftec MP10) and a hydrogenated block copolymer (SEBS, manufactured by KRATON, G1633) in a mass ratio of 1:1 was used. As the solvent for the second binder solution, tetralin was used. Next, the slurry was coated on the current collector of Example 1-1, and for the obtained coated film, it was dried at 100°C for 1 hour in a vacuum atmosphere to prepare the electrode plate of Example 2-1.

[0283] <Comparative Example 2-1>

[0284] Except that solution-polymerized styrene-butadiene rubber (modified SBR, manufactured by Asahi Kasei, Asaprene Y031) was used as the second binder, the electrode plate of Comparative Example 2-1 was prepared in the same manner as in Example 2-1.

[0285] [Peeling Test]

[0286] Using the method described previously, the peeling strength of the electrode plates of Example 2-1 and Comparative Example 2-1 was measured. The results are shown in Table 2. Regarding the measurement of the peeling strength, each electrode plate was measured 3 times. The "peeling strength" shown in Table 2 is the average of the values obtained from the 3 measurements.

[0287] Table 2

[0288]

[0289] From the results shown in Table 2, when LTO is used as the active material of the electrode layer, in the electrode plate of Example 2-1 where an aromatic super engineering plastic is used as the first binder and a styrene-based elastomer with a molar fraction of repeating units from styrene of 0.18 or more is used as the second binder, the peeling strength between the electrode layer and the current collector shows a high value.

[0290] Industrial Applicability

[0291] The electrode plates of the present disclosure can be used in electrochemical devices such as batteries and capacitors.

Claims

1. An electrode plate, comprising: a current collector having a substrate and a coating layer covering the substrate, and an electrode layer disposed on the current collector, the coating layer containing conductive carbon and a first binder, the electrode layer containing a second binder, the first binder containing an aromatic super engineering plastic, and the second binder containing a styrene-based elastomer having a molar fraction of repeating units derived from styrene of 0.18 or more.

2. The electrode plate according to claim 1, wherein, The aromatic super engineering plastic contains polyimide.

3. The electrode plate according to claim 1, wherein, The substrate contains aluminum or an aluminum alloy.

4. The electrode plate according to claim 1, wherein, The electrode layer further contains a solid electrolyte.

5. The electrode plate according to claim 4, wherein, The solid electrolyte contains a sulfide solid electrolyte.

6. A battery, comprising: a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode, and at least one selected from the positive electrode and the negative electrode is the electrode plate according to claim 1.

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