Solid-state battery cathode and solid-state batteries and electronic devices containing it

Abstract

This invention discloses a solid-state battery cathode and a solid-state battery and electronic device containing the same. The solid-state battery cathode includes a cathode current collector and a cathode material layer disposed on at least one surface of the cathode current collector; the cathode material layer includes a composite cathode material and a solid electrolyte, the composite cathode material includes a cathode material and a fluorine-containing coating layer covering the surface of the cathode material, the fluorine-containing coating layer including nano-LiF and carbon. This solid-state battery cathode has low porosity, and solid-state batteries using this cathode exhibit excellent cycle performance and rate performance.

Description

Technical Field

[0001] This invention relates to a solid-state battery cathode and a solid-state battery and electronic device containing the cathode. Background Technology

[0002] The positive electrode of a lithium-ion battery is a porous electrode with a porosity typically ranging from 10% to 30%. In lithium-ion batteries based on liquid electrolytes, the fluidity and wettability of the liquid electrolyte ensure sufficient contact between the electrode particles and the electrolyte, guaranteeing normal ion transport within the porous electrode. However, in solid-state batteries, because solid electrolyte particles lack fluidity, ion and electron transport within the positive electrode relies on applying significant external force to the electrode sheet to minimize porosity and ensure good solid-solid contact between the positive electrode particles / solid electrolyte and between the positive electrode particles and conductive carbon. However, limited by the malleable properties of the aluminum foil current collector, this external force cannot achieve a high level of electrode density.

[0003] In solid-state batteries, the positive electrode is composed of active electrode particles, a solid electrolyte, conductive carbon, and a binder. The electrode / electrolyte and electrode / conductive carbon interfaces are rigid, and the pores at these interfaces hinder the transport of ions and electrons. Furthermore, commonly used sulfide solid electrolytes have a narrow electrochemical window, and when in contact with the positive electrode, especially a ternary cathode, they undergo continuous side reactions, forming an electrochemically inert and highly impedance side reaction layer at the interface. All these issues limit the cycle life and rate performance of solid-state batteries. Summary of the Invention

[0004] To address the aforementioned problems of existing solid-state batteries, this invention provides a solid electrolyte layer, a solid-state battery containing the same, and an electronic device. The positive electrode of this solid-state battery has low porosity, and the solid-state battery obtained using this positive electrode exhibits excellent cycle performance and rate performance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution.

[0006] In a first aspect, the present invention provides a solid-state battery cathode, comprising a cathode current collector and a cathode material layer disposed on at least one surface of the cathode current collector; the cathode material layer comprises a composite cathode material and a solid electrolyte, the composite cathode material comprising a cathode material and a fluorinated coating layer covering the surface of the cathode material, the fluorinated coating layer comprising nano-LiF and carbon.

[0007] In a second aspect, the present invention provides a solid-state battery comprising a solid-state battery positive electrode as described above.

[0008] Thirdly, the present invention provides an electronic device comprising a solid-state battery as described above.

[0009] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0010] The reagents and raw materials used in this invention are all commercially available.

[0011] The positive and progressive effects of this invention are as follows:

[0012] This invention introduces a fluorine-containing coating layer containing nano-LiF and carbon on the surface of the cathode material, resulting in a solid-state battery cathode with low porosity. Solid-state batteries using this cathode exhibit excellent cycle performance and rate performance. Attached Figure Description

[0013] Figure 1 The diagram shows the structure of the solid-state battery in Embodiments 1-19 and 21 of the present invention.

[0014] Reference numerals: 1-Positive electrode current collector; 2-Positive electrode material layer; 21-Fluorine-containing coating layer; 22-Positive electrode material; 23-Solid electrolyte; 24-Binder; 25-Conductive agent; 3-Solid electrolyte layer; 4-Lithium metal layer; 5-Negative electrode current collector. Detailed Implementation

[0015] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0016] solid-state battery positive electrode

[0017] In the solid-state battery cathode provided in the first aspect of the present invention, it includes a cathode current collector and a cathode material layer disposed on at least one surface of the cathode current collector; the cathode material layer includes a composite cathode material and a solid electrolyte, the composite cathode material includes a cathode material and a fluorine-containing coating layer covering the surface of the cathode material, the fluorine-containing coating layer including nano-LiF and carbon.

[0018] This invention reduces the porosity of the solid-state battery cathode by coating the cathode material with a fluorine-containing coating layer containing nano-LiF and carbon, and then expanding it in situ inside the cathode. This improves the solid-solid contact between the active components inside the cathode. At the same time, this in-situ formed CEI layer can provide better protection for the cathode / solid electrolyte interface, thereby improving the overall performance of the solid-state battery, such as rate capability and cycle life.

[0019] In some embodiments, the primary particle size of the nano-LiF is less than 100 nm, preferably less than 50 nm, and more preferably 20-31 nm, such as 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 28 nm, or 29 nm. The primary particle size of the nano-LiF refers to the maximum straight-line distance between any two points on the edge line of a primary particle in the SEM image of the nano-LiF.

[0020] In some embodiments, the mass percentage of nano-LiF in the fluorine-containing coating layer of the composite cathode material is 0.01 wt.% to 0.5 wt.%, for example, 0.08 wt.%, 0.15 wt.%, 0.23 wt.%, 0.31 wt.%, 0.38 wt.%, 0.36 wt.%, 0.24 wt.%, 0.13 wt.%, 0.10 wt.%, 0.22 wt.%, 0.18 wt.%, 0.06 wt.%, or 0.25 wt.%.

[0021] In some embodiments, the carbon content in the fluorinated coating layer accounts for 0.01 wt.% to 0.5 wt.% of the composite cathode material by mass, for example, 0.04 wt.%, 0.09 wt.%, 0.13 wt.%, 0.18 wt.%, 0.22 wt.%, 0.21 wt.%, 0.14 wt.%, 0.08 wt.%, 0.07 wt.%, 0.05 wt.%, or 0.15 wt.%. The carbon content refers to the content of elemental carbon derived from the lithium intercalation reaction of fluorinated carbon as a raw material.

[0022] In some embodiments, the composite cathode material further includes a solid electrolyte coating layer, which coats the surface of the fluorine-containing coating layer.

[0023] In some embodiments, the primary particle size of the solid electrolyte is 100~4000 nm, preferably 100~1000 nm, for example, 340 nm or 410 nm. The primary particle size of the solid electrolyte refers to the maximum straight-line distance between any two points on the edge line of a particle in a SEM image of the solid electrolyte.

[0024] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes and / or halide solid electrolytes.

[0025] The sulfide solid electrolyte can be a conventionally used sulfide solid electrolyte in the art, preferably including Li3PS4, Li 10 GeP2S 12 and Li 10SiP2S 12 One or more of them.

[0026] The halide solid electrolyte can be a conventionally used halide solid electrolyte in the art, preferably including Li. a MX b And / or sulfide-germanium ore type electrolytes. Wherein, Li a MX b In this compound, X is a halogen such as F, Cl, Br, or I, and M is a metallic element. The values ​​of a and b satisfy the following conditions: b is 4, 6, or 8, and a and b satisfy the principle of electroneutrality. For example, when b=6 and M is trivalent Y, a=3, and the compound is Li3YCl6. For example, when b=6 and M is trivalent In, a=3, and the compound is Li3InCl6.

[0027] The silver-germanium sulfide electrolyte preferably includes one or more of Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0028] The halide solid electrolyte preferably includes one or more of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3InCl6 and Li3YCl6.

[0029] In some preferred embodiments, the solid electrolyte includes Li3PS4, Li 10 GeP2S 12 Li 10 SiP2S 12 One or more of Li3InCl6, Li3YCl6, Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0030] In some embodiments, the solid electrolyte accounts for 1 wt.% to 20 wt.% of the mass of the positive electrode material layer, for example, 10 wt.% or 15 wt.%.

[0031] In some embodiments, the mass ratio of the positive electrode material to the solid electrolyte is (80~90):(1~20), for example, 86:10.

[0032] In some implementations, the cathode material includes one or more of ternary cathode materials, phosphate cathode materials, and spinel cathode materials.

[0033] The ternary cathode material can be a conventional nickel-cobalt-manganese ternary cathode material and / or a nickel-cobalt-aluminum ternary cathode material in the art. Nickel-cobalt-manganese ternary cathode materials or nickel-cobalt-aluminum ternary cathode materials containing doped elements are also within the scope of the ternary cathode materials of the present invention.

[0034] The phosphate-based cathode material can be a conventional phosphate-containing cathode material in the art, preferably including lithium iron phosphate or lithium manganese iron phosphate materials, such as LiFePO4 or LiFe 0.4 Mn 0.6 PO4, lithium iron phosphate materials containing doped elements or lithium manganese iron phosphate materials are also within the scope of phosphate cathode materials of the present invention.

[0035] The spinel-type cathode material can be a conventional cathode material with a spinel structure in the art, preferably including lithium manganese oxide, lithium cobalt oxide, and lithium nickel manganese oxide, such as LiMn2O4 and LiNi. 0.5 Mn 1.5 O4, lithium manganese oxide, lithium cobalt oxide, or lithium nickel manganese oxide containing doped elements are also within the scope of spinel-type cathode materials of this invention.

[0036] In some embodiments, the primary particle size of the composite cathode material is 0.05~50 μm, preferably 0.1~5.0 μm, for example 0.28 μm, 1.7 μm, 2.8 μm or 4.6 μm. The primary particle size of the composite cathode material refers to the maximum straight-line distance between any two points on the edge line of a particle in the SEM image of the composite cathode material.

[0037] In some preferred embodiments, the primary particle size of the composite cathode material is 0.5~5 μm, for example 1.7 μm, and the cathode material is a ternary cathode material.

[0038] In some preferred embodiments, the primary particle size of the composite cathode material is 0.05~5 μm, for example 0.28 μm, and the cathode material is LiFePO4 and LiFe. 0.4 Mn 0.6 One or more of PO4.

[0039] In some preferred embodiments, the primary particle size of the composite cathode material is 1.0~10 μm, for example 4.6 μm, and the cathode material is LiMn2O4 and LiNi. 0.5 Mn 1.5 One or more of O4.

[0040] In some embodiments, the positive electrode material layer further includes a conductive agent. The conductive agent is a reagent used to ensure that the electrode has good charge-discharge performance. It can be selected from graphite materials such as natural graphite and artificial graphite; carbon black materials such as conductive carbon black (Super P, abbreviated as SP), acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal cracking black; conductive fibers such as vapor-grown carbon fiber reinforcement (VGCF), carbon fiber, and metal fiber; metal powders such as fluorinated carbon powder, aluminum powder, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; carbon nanotubes such as single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs); and conductive metal oxides or polyphenylene derivatives such as titanium dioxide, for example, conductive carbon black.

[0041] In some preferred embodiments, the conductive agent is one or more of VGCF, SP, SWCNT, MWCNT, and graphene.

[0042] In some embodiments, the positive electrode material layer further includes a binder. The binder can be a component that facilitates bonding between the positive electrode material and the conductive agent. It is typically selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers, such as PTFE.

[0043] In some preferred embodiments, the adhesive is one or more of PTFE, PVDF, and PAN.

[0044] In some embodiments, the cathode material layer includes a composite cathode material, Li3PS4, polytetrafluoroethylene, and conductive carbon black.

[0045] In some specific implementations, the mass ratio of the composite cathode material, Li3PS4, polytetrafluoroethylene, and conductive carbon black is 86:10:2:2.

[0046] In this invention, the positive electrode current collector can be a conventional positive electrode current collector in the art. For the positive electrode current collector, materials that do not cause chemical changes and have high conductivity can be used without limitation. For example, commonly used materials include stainless steel, aluminum, nickel, titanium, or calcined carbon, or aluminum or stainless steel materials surface-treated with carbon, nickel, titanium, silver, etc. To enhance adhesion, micro-embossing can be formed on the surface of the positive electrode current collector. The positive electrode current collector can be used in various forms, such as films, sheets, foils, meshes, or porous bodies.

[0047] In some alternative implementations, the positive current collector is aluminum foil.

[0048] In some alternative embodiments, the thickness of the positive current collector can be 8 to 16 μm, for example 15 μm.

[0049] In some implementations, the porosity of the solid-state battery cathode is ≤15%.

[0050] In some embodiments, the solid-state battery cathode is formed by charging and discharging a cathode intermediate, wherein the cathode intermediate includes a cathode current collector and a cathode material layer intermediate disposed on at least one surface of the cathode current collector; the cathode material layer intermediate includes a composite cathode material intermediate and a solid electrolyte, the composite cathode material intermediate includes a cathode material and a coating agent coated on the surface of the cathode material, the coating agent including fluorinated carbon.

[0051] In some preferred embodiments, the fluorinated carbon includes one or more of fluorinated graphite, fluorinated acetylene black, fluorinated hard carbon, and fluorinated carbon nanotubes.

[0052] In some preferred embodiments, the fluorinated carbon is CFx, where x = 0.5~1.2.

[0053] In some preferred embodiments, the fluorinated carbon has a size of 10 to 500 nm in at least one of the three-dimensional dimensions.

[0054] In some preferred embodiments, the fluorinated carbon accounts for 0.1 wt.% to 10 wt.% of the mass percentage of the pre-coated composite cathode, preferably 0.1 wt.% to 2 wt.%.

[0055] In some preferred embodiments, the charge-discharge cycle number is at least 2 times.

[0056] In some preferred embodiments, the charging and discharging voltage range is 2.0~4.3V.

[0057] In some preferred embodiments, the charge / discharge rate is 0.01C to 0.5C, for example, 0.1C.

[0058] solid-state batteries

[0059] The solid-state battery provided in the second aspect of the present invention includes a solid-state battery positive electrode as described above.

[0060] In this invention, the solid-state battery includes a negative electrode, a solid electrolyte layer, and a solid-state battery positive electrode as described above.

[0061] negative electrode

[0062] In some implementations, the thickness of the negative electrode is 0.1 to 200 μm, for example, 40 μm or 50 μm.

[0063] In some embodiments, the negative electrode is a lithium-plated negative electrode current collector. The lithium-plated negative electrode current collector includes a negative electrode current collector and a lithium metal layer disposed on at least one surface of the negative electrode current collector. The lithium-plated negative electrode current collector is, for example, a lithium-plated copper foil. The thickness of the lithium metal layer in the lithium-plated copper foil is, for example, 30 μm, and the thickness of the copper foil is, for example, 10 μm.

[0064] In some embodiments, the negative electrode includes a negative electrode current collector and a negative electrode material layer disposed on at least one surface of the negative electrode current collector, the negative electrode material layer comprising a negative electrode material.

[0065] In this invention, the negative electrode current collector can be a conventional negative electrode current collector in the art. The negative electrode current collector, serving as the substrate supporting the negative electrode material layer, is typically a metal foil with a thickness of 3-500 μm. There are no particular limitations on the material, as long as it has high conductivity and does not produce a chemical reaction in the secondary battery system. For example, it can be a foil formed by surface treatment of nickel, titanium, aluminum, silver, stainless steel, carbon, etc. The negative electrode current collector usually has a smooth surface, but fine textures can also be formed on its surface to improve the adhesion between the negative electrode material layer and the current collector. Besides foil, the negative electrode current collector can also be used in any one or more combinations of various forms such as film, mesh, porous, foam, or non-woven fabric. Generally, the negative electrode current collector is copper foil.

[0066] In this invention, the negative electrode material can be a negative electrode material conventionally used in the art, preferably including one or more of artificial graphite, natural graphite, soft carbon, hard carbon, mesophase carbon microspheres, silicon suboxide and silicon carbide materials, such as silicon carbide materials.

[0067] In some implementations, the negative electrode material layer further includes a conductive agent.

[0068] The conductive agent is not particularly limited, as long as it is conductive and does not cause chemical changes in the battery. For example, specific materials that can be used include: graphite, such as natural or artificial graphite; carbon-based materials, such as conductive carbon black (Super P), carbon nanotubes (CNTs), acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, or carbon fiber; metal powders or metal fibers, such as copper, nickel, aluminum, or silver; conductive whiskers, such as zinc oxide whiskers or potassium titanate whiskers; conductive metal oxides, such as titanium dioxide; or conductive polymers, such as polyphenylene derivatives.

[0069] In some implementations, the negative electrode material layer further includes a binder.

[0070] The type of adhesive is not particularly limited and can be selected from polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyvinyl alcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid (PAA), ethylene-propylene-diene terpolymer and its sulfonates, styrene-butadiene rubber (SBR), fluororubber and various copolymers, such as PTFE.

[0071] In some embodiments, the negative electrode material layer includes a negative electrode material and a binder.

[0072] In some specific embodiments, the negative electrode material layer comprises silicon-carbon material and PTFE, wherein the mass ratio of silicon-carbon material to PTFE is, for example, 99:1.

[0073] In some embodiments, the method for preparing the negative electrode includes the following steps: thoroughly mixing the components of the negative electrode material layer to obtain a mixture; pressing the mixture into a sheet to obtain a negative electrode; wherein the mixture forms a negative electrode material layer.

[0074] In this invention, the solid-state battery can be prepared by conventional methods in the art, which may involve stacking a positive electrode and a solid electrolyte layer and pressing them together to form a solid battery, and then attaching a negative electrode to the surface of the solid electrolyte layer away from the positive electrode; or it may involve stacking a positive electrode, a solid electrolyte layer, and a negative electrode in sequence and then pressing them together to form the solid battery.

[0075] electronic devices

[0076] The electronic device provided in the third aspect of the present invention includes a solid-state battery as described above.

[0077] For example, the electronic devices described in this invention may be, but are not limited to, mobile devices (such as mobile phones, tablets, laptops, video recorders, portable printers / copiers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems and backup power supplies, etc.

[0078] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention. The present invention is further illustrated below by way of embodiments, but this does not limit the present invention to the scope of the described embodiments. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or according to the product instructions. Unless otherwise specified, all reagents and raw materials used in the present invention are commercially available.

[0079] The fluorinated carbon (CFx) used in the following examples and comparative examples were all purchased from Xiamen Zhongke Xifu Technology Co., Ltd.; VGCF was purchased from Showa Denko, Japan.

[0080] Example 1:

[0081] (1) Preparation of composite cathode material intermediate: The cathode material LiNi 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 CF was obtained by mixing the components evenly at a mass ratio of 99.9:0.1. 0.8 Coated cathode material;

[0082] (2) Preparation of the positive electrode intermediate: The CF 0.8 The coated cathode material was uniformly mixed with Li3PS4 (particle size 800 nm), PTFE and VGCF at a mass ratio of 86:10:2:2 to obtain a mixture. This mixture was then coated onto one surface of an aluminum foil (15 μm) and pre-pressed into a sheet (pressing pressure 200 MPa). The density of the cathode material intermediate was 18 mg / cm³. 2 The thickness of the intermediate layer of the positive electrode material is 60 μm.

[0083] (3) Preparation of solid electrolyte layer: Li3PS4 solid electrolyte powder is pre-pressed into sheets (pressing pressure is 200MPa).

[0084] (4) Solid-state battery preparation: The positive electrode intermediate and the solid electrolyte layer are stacked together and isostatically pressed under a pressure of 500 MPa (where the positive electrode material intermediate is close to the solid electrolyte layer). Then, lithium-plated copper foil (the lithium metal layer is set on one surface of the copper foil, where the copper foil thickness is 10 μm and the lithium metal layer thickness is 30 μm) is attached to the side of the solid electrolyte layer away from the positive electrode intermediate and encapsulated.

[0085] (5) Activation (charge and discharge): The solid-state battery is activated by charging and discharging it for 2 cycles at 0.1C and 2.0~4.3V (1C=200mA / g).

[0086] After this activation treatment, the cathode intermediate forms the solid-state battery cathode, and the composite cathode material intermediate forms the composite cathode material.

[0087] Example 2:

[0088] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF0.8 The mass ratio is 99.8:0.2, and the remaining steps and conditions are the same as in Example 1.

[0089] Example 3:

[0090] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99.7:0.3, and the remaining steps and conditions are the same as in Example 1.

[0091] Example 4:

[0092] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99.6:0.4, and the remaining steps and conditions are the same as in Example 1.

[0093] Example 5:

[0094] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99.5:0.5, and the remaining steps and conditions are the same as in Example 1.

[0095] Example 6:

[0096] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99.3:0.7, and the remaining steps and conditions are the same as in Example 1.

[0097] Example 7:

[0098] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99.2:0.8, and the remaining steps and conditions are the same as in Example 1.

[0099] Example 8:

[0100] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 99:1, and the remaining steps and conditions are the same as in Example 1.

[0101] Example 9:

[0102] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 98:2, and the remaining steps and conditions are the same as in Example 1.

[0103] Example 10:

[0104] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 95:5, and the remaining steps and conditions are the same as in Example 1.

[0105] Example 11:

[0106] The only difference between this embodiment and Embodiment 1 is that in the preparation of the composite cathode material intermediate, the cathode material LiNi... 0.9 Co 0.05 Mn 0.05 O2 and fluorinated carbon CF 0.8 The mass ratio is 90:10, and the remaining steps and conditions are the same as in Example 1.

[0107] Example 12:

[0108] The only difference between this embodiment and Embodiment 5 is that in the preparation of the composite cathode material intermediate, CF is used. 0.5 Replace CF 0.8 The mass ratio is 90:10, and the remaining steps and conditions are the same as in Example 5.

[0109] Example 13:

[0110] The only difference between this embodiment and Embodiment 5 is that in the preparation of the composite cathode material intermediate, CF is used. 1.2 Replace CF 0.8 The mass ratio is 90:10, and the remaining steps and conditions are the same as in Example 5.

[0111] Example 14:

[0112] The only difference between this embodiment and Embodiment 5 is that in the preparation of the composite cathode material intermediate, CF is used. 0.4 Replace CF 0.8 The mass ratio is 90:10, and the remaining steps and conditions are the same as in Example 5.

[0113] Example 15:

[0114] The only difference between this embodiment and Embodiment 5 is that in the preparation of the composite cathode material intermediate, CF is used. 1.3 Replace CF 0.8 The mass ratio is 90:10, and the remaining steps and conditions are the same as in Example 5.

[0115] Example 16:

[0116] The only difference between this embodiment and Embodiment 5 is that in the preparation of the positive electrode intermediate, Li6PS5Cl (particle size of 900nm) is used instead of Li3PS4, and the other steps and conditions are the same as in Embodiment 5.

[0117] Example 17:

[0118] The only difference between this embodiment and Embodiment 5 is that, in the preparation of the composite cathode material intermediate, the cathode material used is LiFe. 0.4 Mn 0.6 PO4 replaces LiNi 0.9 Co 0.05 Mn 0.05 O2, the remaining steps and conditions are the same as in Example 5.

[0119] Example 18:

[0120] The only difference between this embodiment and Embodiment 5 is that, in the preparation of the composite cathode material intermediate, LiMn2O4 is used instead of LiNi as the cathode material. 0.9 Co 0.05 Mn 0.05 O2, the remaining steps and conditions are the same as in Example 5.

[0121] Example 19:

[0122] The only difference between this embodiment and Embodiment 5 is that, in the preparation of the composite cathode material intermediate, the cathode material used is LiNi. 0.5 Mn 1.5 O4 replaces LiNi 0.9 Co 0.05 Mn 0.05 O2, the remaining steps and conditions are the same as in Example 5.

[0123] Example 20:

[0124] The difference between this embodiment and Embodiment 5 is that a silicon-carbon electrode layer is used instead of lithium-plated copper foil in the fabrication of the solid-state battery.

[0125] The preparation of the silicon-carbon electrode: silicon-carbon material (BTR BSM-2) and PTFE were mixed evenly in a high-speed mixer at a mass ratio of 99:1, and then pressed onto a 10μm copper foil at 100MPa to obtain a silicon-carbon electrode (electrode thickness of 60 μm).

[0126] Solid-state battery fabrication: The positive electrode intermediate, solid electrolyte layer and silicon-carbon electrode layer are placed in a mold in sequence, then pressed tightly under an isostatic pressure of 500 MPa and encapsulated.

[0127] The remaining conditions and steps are the same as in Example 5.

[0128] Example 21:

[0129] The difference between this embodiment and Embodiment 5 is that in the preparation of the cathode intermediate, the mass ratio of the composite cathode material intermediate, Li3PS4, PTFE, and VGCF is 81:15:2:2. The remaining conditions and steps are the same as in Embodiment 5.

[0130] Schematic diagrams of the solid-state batteries obtained in Examples 1-19 and 21 are shown below. Figure 1 As shown. By Figure 1 As can be seen, along the direction away from the positive electrode current collector 1, the solid-state battery sequentially includes a positive electrode current collector 1, a positive electrode material layer 2, a solid electrolyte layer 3, a lithium metal layer 4, and a negative electrode current collector 5; wherein, the positive electrode material layer 2 includes a positive electrode material 22, a solid electrolyte 23, a binder 24, and a conductive agent 25, and the surface of the positive electrode material 22 is coated with a fluorine-containing coating layer 21; wherein, the positive electrode current collector 1 and the positive electrode material layer 2 form the positive electrode of the solid-state battery, and the lithium metal layer 4 and the negative electrode current collector 5 form the negative electrode of the solid-state battery.

[0131] Comparative Example 1:

[0132] The difference between this comparative example and Example 1 is that step (1) is not performed, that is, the positive electrode material LiNi is not... 0.9 Co 0.05 Mn 0.05 O2 is used for coating, and step (2) directly uses the positive electrode material LiNi. 0.9 Co 0.05 Mn 0.05 O2 replaces CF 0.8 The coating of the positive electrode material follows the same conditions and steps as in Example 1. The surface of the positive electrode material in the resulting solid-state battery positive electrode has no fluorine-containing coating layer.

[0133] Comparative Example 2:

[0134] The difference between this comparative example and Example 16 is that step (1) is not performed, that is, the positive electrode material LiNi is not... 0.9 Co 0.05 Mn 0.05 O2 is used for coating, and step (2) directly uses the positive electrode material LiNi. 0.9 Co 0.05 Mn 0.05 O2 replaces CF 0.8 The coating of the positive electrode material follows the same conditions and steps as in Example 16. The resulting solid-state battery positive electrode material has no fluorine-containing coating layer on its surface.

[0135] Comparative Example 3:

[0136] The difference between this comparative example and Example 17 is that step (1) is not performed, that is, the positive electrode material LiFe is not... 0.4 Mn 0.6 PO4 is used for coating, and step (2) directly uses LiFe as the positive electrode material. 0.4 Mn 0.6 PO4 replaces CF 0.8 The coating of the positive electrode material follows the same conditions and steps as in Example 17. The resulting solid-state battery positive electrode material has no fluorine-containing coating layer on its surface.

[0137] Comparative Example 4:

[0138] The difference between this comparative example and Example 18 is that step (1) is omitted, i.e., the cathode material is not coated with LiMn2O4, and step (2) directly replaces CF with LiMn2O4 as the cathode material. 0.8 The coating of the positive electrode material follows the same conditions and steps as in Example 18. The resulting solid-state battery positive electrode material has no fluorine-containing coating layer on its surface.

[0139] Comparative Example 5:

[0140] The difference between this comparative example and Example 19 is that step (1) is omitted, i.e., LiNi is not used as the cathode material. 0.5 Mn 1.5 O4 is used for coating, and step (2) directly uses LiNi as the positive electrode material. 0.5 Mn 1.5 O4 replaces CF 0.8 The coating of the positive electrode material follows the same conditions and steps as in Example 19. The resulting solid-state battery positive electrode material has no fluorine-containing coating layer on its surface.

[0141] Some parameters and conditions in Examples 1-21 and Comparative Examples 1-5 are shown in Tables 1 and 2.

[0142] Example 1

[0143] (1) Porosity and porosity change rate of the cathode of solid-state battery

[0144] The porosity of the solid-state battery cathodes prepared in Examples 1-21 and Comparative Examples 1-5 was tested to obtain A0; and the activated solid-state batteries in Examples 1-21 and Comparative Examples 1-5 were disassembled, the solid-state battery cathodes were peeled off, and their porosity was tested to obtain A1 (corresponding to "Porosity of Solid-State Battery Cathode" in Table 2); the porosity change rate of the solid-state battery = (A0-A1) / A0×100%; wherein, the porosity test method of the solid-state battery cathode refers to the mercury intrusion porosimetry test of the solid-state battery cathode in the national standard GB / T 21650.1~2008.

[0145] The measurement results are shown in Table 2.

[0146] (2) Primary particle size of solid electrolyte, primary particle size of composite cathode material and primary particle size of nano LiF

[0147] By performing SEM analysis on the solid-state battery cathode using a ZEISS Sigma microscope (equipped with an energy dispersive spectroscopy (EDS) accessory), the primary particle size of the solid electrolyte, the composite cathode material, and the nano-LiF can be measured from the obtained SEM images. Specifically:

[0148] Primary particle size of solid electrolyte and composite cathode material: SEM (Scanning Electron Microscopy) was used to measure the solid-state battery cathodes obtained in the examples and comparative examples, respectively. SEM images were obtained at a voltage of 5kV and a magnification of 5K. At least 200 particles were randomly selected from each SEM image (EDS testing was used to distinguish between solid electrolyte particles and composite cathode material particles; at least 200 particles were selected for each material). The particle size was measured using ImageJ (the maximum straight-line distance between any two points on the particle edge). Three SEM images were obtained for each sample, and the particle size of at least 600 particles was measured (at least 600 particles for each material). The average value was taken to obtain the primary particle size of the solid electrolyte and the composite cathode material. The test results are shown in Tables 1 and 2.

[0149] Primary particle size of nano-LiF: SEM images of the solid-state battery cathodes obtained in the examples and comparative examples were performed using a scanning electron microscope (SEM). The voltage was 5 kV, and the magnification was 5 K. At least 200 particles were randomly selected from each SEM image (to aid EDS testing to identify lithium fluoride particles). The primary particle size (maximum diagonal length of the particle) was measured using ImageJ. Three SEM images were obtained for each sample, and the particle size of at least 600 particles was measured. The average value was taken to obtain the primary particle size of LiF. The test results are shown in Table 2.

[0150] (3) TEM test

[0151] The solid-state battery cathode was subjected to TEM testing (Hitachi, HT~7800, equipped with EDS accessory) at a voltage of 10kV and a magnification of 20K. The presence of a fluorine-containing coating layer in the solid-state battery cathode can be seen from the TEM image and EDS.

[0152] (4) LiF content and carbon content in the cathode of solid-state battery

[0153] LiF has characteristic peaks in solid-state nuclear magnetic resonance (SS-NMR) spectra. Its content was obtained by quantitative analysis of solid-state nuclear magnetic resonance, and the test results are recorded in Table 2.

[0154] The carbon content is the carbon content converted from the lithium intercalation reaction of fluorinated carbon as raw material. This content can be quantitatively estimated by the fluorine content. For a given coated fluorinated carbon CFx, the ratio of activated carbon content to lithium fluoride content is 0.462 / x, where x is the subscript of F in the coated fluorinated carbon CFx. The calculation method for this ratio is as follows, and the calculation results are shown in Table 2.

[0155] CFx + xLi = C + xLiF

[0156] The relative atomic mass of carbon is 12, and the relative molecular mass of lithium fluoride is 26.

[0157] Mass of carbon / Mass of lithium fluoride = 12 / 26x = 0.462 / x.

[0158] Regarding carbon content, the actual carbon content obtained by directly testing the cathode of a solid-state battery will be higher than the calculated value above. This is because the cathode material may contain carbon elements, unreacted fluorinated carbon, and residual alkali, which will result in a higher measured carbon content.

[0159] Example 2

[0160] The solid-state batteries in Examples 1-21 and Comparative Examples 1-5 were tested for cycle performance and rate performance, respectively. Specifically:

[0161] (1) Cyclic performance test: The cycle performance of the activated solid-state battery was tested by constant current-constant voltage charging and constant current discharging mode. The charging rate was 0.5C, the constant voltage cutoff current was 0.05C, the discharge rate was 1C, and the voltage range was 2.5~4.3V. Cycling was carried out until the ratio of the discharge capacity of the nth cycle to the discharge capacity of the first cycle of 1C was less than 80%. The capacity retention rate of the n~1th cycle was defined as 80%, and the number of cycles was recorded as n~1 cycles, which is the cycle life of the battery.

[0162] (2) Rate performance test: The activated solid-state battery is charged at a charging rate of 0.33C at 2.5~4.3V, and the discharge capacity at 0.33C and 3C rates is tested in sequence. The ratio of 3C discharge capacity to 0.33C discharge capacity is the 3C / 0.33C capacity retention rate.

[0163] The measurement results are shown in Table 3.

[0164] Table 1

[0165] serial number Types of cathode materials CFx CFx content / wt.% Solid electrolyte content in the cathode of a solid-state battery / wt.% Types of solid electrolytes Solid electrolyte primary particle size / nm negative electrode Example 1 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.1 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 2 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.2 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 3 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.3 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 4 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.4 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 5 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 6 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.7 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 7 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.8 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 8 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 1 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 9 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 2 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 10 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 11 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 10 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 12 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.5 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 13 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 1.2 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 14 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.4 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 15 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 1.3 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 16 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li6PS5Cl]]> 410 Lithium-plated copper foil Example 17 <![CDATA[LiFe 0.4 Mn 0.6 PO4]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 18 <![CDATA[LiMn2O4]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 19 <![CDATA[LiNi 0.5 Mn 1.5 O4]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Example 20 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.5 10 <![CDATA[Li3PS4]]> 340 silicon carbide electrode Example 21 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> <![CDATA[CF 0.8 ]]> 0.5 15 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Comparative Example 1 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> / / 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Comparative Example 2 <![CDATA[LiNi 0.9 What 0.05 Mn 0.05 O2]]> / / 10 <![CDATA[Li6PS5Cl]]> 410 Lithium-plated copper foil Comparative Example 3 <![CDATA[LiFe a Mn b PO4]]> / / 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Comparative Example 4 <![CDATA[LiMn2O4]]> / / 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil Comparative Example 5 <![CDATA[LiNi 0.5 Mn 1.5 O4]]> / / 10 <![CDATA[Li3PS4]]> 340 Lithium-plated copper foil

[0166] Note: In Table 1, " / " indicates that the condition parameter is not involved in the specific experiment.

[0167] Table 2

[0168] serial number Nano LiF content in solid-state battery cathode / wt.% Primary particle size of nano-LiF / nm Carbon content in solid-state battery cathode / wt.% Primary particle size of composite cathode material (μm) Porosity of solid-state battery cathode / % Porosity change rate of solid-state battery cathode / % Example 1 0.08 23 0.04 1.7 13.4 11.8 Example 2 0.15 23 0.09 1.7 12.8 15.8 Example 3 0.23 22 0.13 1.7 12.3 19.1 Example 4 0.31 25 0.18 1.7 11.9 21.7 Example 5 0.38 26 0.22 1.7 11.3 25.7 Example 6 0.36 22 0.21 1.7 11.5 24.3 Example 7 0.24 21 0.14 1.7 12.3 19.1 Example 8 0.15 25 0.09 1.7 12.9 15.1 Example 9 0.13 26 0.08 1.7 13.0 14.5 Example 10 0.10 24 0.07 1.7 13.2 13.2 Example 11 0.08 25 0.05 1.7 13.4 11.8 Example 12 0.22 25 0.13 1.7 12.4 18.4 Example 13 0.24 22 0.14 1.7 12.3 19.1 Example 14 0.15 25 0.09 1.7 12.9 15.1 Example 15 0.18 23 0.11 1.7 12.7 16.4 Example 16 0.38 21 0.22 1.7 11.5 29.9 Example 17 0.06 26 0.04 0.28 13.5 27.8 Example 18 0.15 28 0.09 2.8 12.9 25.9 Example 19 0.22 29 0.13 4.6 12.4 28.3 Example 20 0.25 31 0.15 1.7 12.2 19.7 Example 21 0.31 20 0.18 1.7 11.8 22.4 Comparative Example 1 / / / 1.7 15.2 0.0 Comparative Example 2 / / / 1.7 16.4 0.0 Comparative Example 3 / / / 0.28 18.7 0.0 Comparative Example 4 / / / 2.8 17.4 0.0 Comparative Example 5 / / / 4.6 17.3 0.0

[0169] Note: In Table 2, " / " indicates that the condition parameter is not involved in the specific experiment.

[0170] Table 3

[0171] serial number Solid-state battery cycle life / cycles Solid-state battery capacity retention rate at 3C / 0.33C (%) Example 1 269 61.3 Example 2 287 62.9 Example 3 293 64.3 Example 4 306 65.8 Example 5 395 69.6 Example 6 372 68.2 Example 7 311 64.8 Example 8 272 62.5 Example 9 267 62.1 Example 10 256 61.3 Example 11 245 60.6 Example 12 304 64.4 Example 13 311 64.8 Example 14 272 62.5 Example 15 284 63.2 Example 16 438 68.4 Example 17 430 56.7 Example 18 404 67.9 Example 19 368 59.2 Example 20 432 68.5 Example 21 478 78.4 Comparative Example 1 184 54.5 Comparative Example 2 195 52.2 Comparative Example 3 260 43.1 Comparative Example 4 234 58.9 Comparative Example 5 170 42.0

[0172] As shown in Tables 1-3, by introducing a fluorine-containing coating layer into the solid-state battery cathode in this invention, the porosity of the solid-state battery cathode can be less than 15%, and the battery obtained using this solid-state battery cathode exhibits excellent cycle performance and rate performance. Specifically, the cycle life can reach more than 240 cycles, and the 3C / 0.33C capacity retention rate can reach more than 55%.

[0173] In Examples 1-16 and 20-21, the solid-state battery cathode uses LiNi. 0.9 Co 0.05 Mn 0.05Using O2 as the cathode material, the resulting solid-state battery can achieve a cycle life of over 200 cycles and a 3C / 0.33C capacity retention rate of over 60%. However, in Comparative Examples 1 and 2, the solid-state battery cathode lacks a fluorine coating layer, resulting in a significantly worse cycle life and 3C / 0.33C capacity retention rate.

[0174] In Example 17, the solid-state battery cathode uses LiFe. 0.4 Mn 0.6 Using PO4 as the cathode material, the resulting solid-state battery can achieve a cycle life of up to 430 cycles and a 3C / 0.33C capacity retention rate of up to 56.7%. However, in Comparative Example 3, the solid-state battery cathode does not have a fluorine coating layer, resulting in a significantly worse cycle life and 3C / 0.33C capacity retention rate.

[0175] In Example 18, the solid-state battery uses LiMn2O4 as the cathode material, and the resulting solid-state battery has a cycle life of more than 400 cycles and a 3C / 0.33C capacity retention rate of more than 65%. In contrast, the solid-state battery in Comparative Example 4 does not have a fluorine coating layer, and the cycle life and 3C / 0.33C capacity retention rate of the resulting solid-state battery are significantly reduced.

[0176] In Example 19, the solid-state battery cathode uses LiNi. 0.5 Mn 1.5 Using O4 as the cathode material, the resulting solid-state battery can achieve a cycle life of over 350 cycles and a capacity retention rate of over 59% at 3C / 0.33C. In contrast, the solid-state battery in Comparative Example 5 lacks a fluorine-containing coating layer at the cathode, resulting in a significantly worse cycle life and 3C / 0.33C capacity retention rate.

[0177] In some alternative implementations, the fluorinated carbon content in the composite cathode material intermediate is 0.4 wt.% to 0.8 wt.% (as in Examples 4-8), corresponding to a nano-LiF content of 0.15 wt.% to 0.38 wt.% and a carbon content of 0.09 wt.% to 0.22 wt.% in the solid-state battery cathode. The resulting solid-state battery exhibits a longer cycle life, exceeding 270 cycles. This is likely because an appropriately thick fluorinated coating layer facilitates good electron / ion transport within the electrode and ensures appropriate electronic conductivity.

[0178] In some alternative implementations, fluorinated carbon CF32O3 is present in the composite cathode material intermediate. xWhen x is between 0.5 and 1.2 (as in Examples 5, 12, and 13), the corresponding content of nano-LiF in the solid-state battery cathode is 0.22 wt.% to 0.38 wt.%, and the carbon content is 0.13 wt.% to 0.22 wt.%. The resulting solid-state battery exhibits a longer cycle life, exceeding 300 cycles. This is likely because a fluorinated coating with an appropriate fluorine-to-carbon ratio helps ensure a certain volume expansion rate and internal densification of the electrode, while also ensuring low porosity, sufficient solid-solid contact, and good ion / electron transport at the solid-solid interface.

[0179] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A solid-state battery cathode, characterized by, The solid-state battery positive electrode comprises a positive electrode current collector and a positive electrode material layer arranged on at least one surface of the positive electrode current collector; the positive electrode material layer comprises a composite positive electrode material and a solid-state electrolyte, the composite positive electrode material comprises a positive electrode material and a fluorine-containing coating layer coated on the surface of the positive electrode material, the fluorine-containing coating layer comprises nano LiF and carbon; the porosity of the solid-state battery positive electrode is ≤15%; the primary particle size of the nano LiF is 20 nm-100 nm; the solid-state battery positive electrode is formed by charging and discharging a positive electrode intermediate, wherein the positive electrode intermediate comprises a positive electrode current collector and a positive electrode material layer intermediate arranged on at least one surface of the positive electrode current collector; the positive electrode material layer intermediate comprises a composite positive electrode material intermediate and a solid-state electrolyte, the composite positive electrode material intermediate comprises a positive electrode material and a coating agent coated on the surface of the positive electrode material, and the coating agent comprises carbon fluoride; The mass percentage of the carbon fluoride in the composite positive electrode material intermediate is 0.1 wt.%-10 wt.%.

2. The solid-state battery cathode of claim 1, wherein, The composite positive electrode material satisfies one or both of the following conditions a-b: a. The mass percentage of the nano LiF in the fluorine-containing coating layer in the composite positive electrode material is 0.01 wt.%-0.5 wt.%; b. The mass percentage of the carbon in the fluorine-containing coating layer in the composite positive electrode material is 0.01 wt.%-0.5 wt.%.

3. The solid-state battery cathode of claim 1, wherein, The composite positive electrode material further comprises a solid-state electrolyte coating layer, and the solid-state electrolyte coating layer is coated on the surface of the fluorine-containing coating layer.

4. The solid-state battery cathode of claim 1, wherein, One or more of the following conditions a-h are satisfied: a. The primary particle size of the solid-state electrolyte is 100-4000 nm; b. The solid-state electrolyte comprises a sulfide solid-state electrolyte and / or a halide solid-state electrolyte; c. The mass percentage of the solid-state electrolyte in the positive electrode material layer is 1 wt.%-20 wt.%; d. The mass ratio of the positive electrode material to the solid-state electrolyte is (80-90):(1-20); e. The positive electrode material comprises one or more of a ternary positive electrode material, a phosphate positive electrode material, and a spinel positive electrode material; f. The primary particle size of the composite positive electrode material is 0.05-50 μm; g. The positive electrode material layer further comprises a conductive agent; h. The positive electrode material layer further comprises a binder.

5. The solid-state battery cathode of claim 1, wherein, One or more of the following conditions a-c are satisfied for the carbon fluoride: a. The carbon fluoride comprises one or more of fluorinated graphite, fluorinated acetylene black, fluorinated hard carbon, and fluorinated carbon nanotubes; b. The carbon fluoride is CFx, x=0.5-1.2; c. The carbon fluoride has a dimension of 10-500 nm in at least one direction of three dimensions.

6. The solid-state battery cathode of claim 1, wherein, One or more of the following conditions a-c are satisfied for the charging and discharging: a. The number of cycles of the charging and discharging is at least 2; b. The voltage range of the charging and discharging is 2.0-4.3 V; c. The rate of the charging and discharging is 0.01 C-0.5 C.

7. A solid state battery, characterized by The solid-state battery positive electrode comprises the solid-state battery positive electrode according to any one of claims 1-6.

8. An electronic device, comprising: The solid-state battery comprises the solid-state battery according to claim 7.

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