Solid electrolyte layer, and solid-state battery and electronic device comprising same

Abstract

The invention discloses a solid-state electrolyte layer, a solid-state battery containing the solid-state electrolyte layer, and electronic equipment containing the solid-state electrolyte layer. The solid electrolyte layer comprises a solid electrolyte and a non-metal nano material; the non-metal nano material comprises one or more of a boron nano material, a sulfur nano material, a selenium nano material, a red phosphorus nano material and a black phosphorus nano material; the non-metal nano material accounts for 0.01 wt.%-2wt.% of the mass of the solid electrolyte layer; and the particle size of the non-metal nano material is less than 200 nm. The solid-state electrolyte layer can effectively inhibit overgrowth of lithium dendrites and has good lithium ion conducting capacity and excellent limiting current density, and the obtained solid-state battery has good short-circuit failure resisting capacity, low self-discharge rate and excellent cycle performance.

Description

Technical Field

[0001] This invention relates to a solid electrolyte layer and solid-state batteries and electronic devices containing the same. Background Technology

[0002] Traditional lithium-ion batteries use ester solvents as electrolytes, which are highly susceptible to leakage and fire hazards, and their energy density is nearing its limit. Solid-state batteries use solid electrolytes, which are non-flammable, and the higher mechanical strength of solid electrolytes can effectively suppress lithium dendrites. Therefore, solid-state batteries have become the preferred choice for next-generation high-energy-density and high-safety batteries. However, actual research has found that lithium dendrites can still grow along the pores of solid electrolytes, causing a series of problems.

[0003] During the charging and discharging process of solid-state batteries, the current density is uneven at the electrolyte / negative electrode solid-solid interface. Lithium dendrites will grow along the pores and grain boundaries between solid electrolyte particles. After high current density or cycling, the dendrites will eventually penetrate the electrolyte and cause a short circuit. At the same time, the growth of lithium dendrites will induce mechanical stress inside the electrolyte, generating mechanical cracks inside the electrolyte, which will further deteriorate the battery performance. 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. This solid electrolyte layer effectively suppresses excessive lithium dendrite growth and exhibits good lithium-ion conductivity, excellent limiting current density, and the resulting solid-state battery demonstrates good resistance to short-circuit failure, low self-discharge rate, and excellent cycle 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 electrolyte layer comprising a solid electrolyte and non-metallic nanomaterials, wherein the non-metallic nanomaterials include one or more of boron nanomaterials, sulfur nanomaterials, selenium nanomaterials, red phosphorus nanomaterials, and black phosphorus nanomaterials; the non-metallic nanomaterials account for 0.01 wt.% to 2 wt.% of the mass of the solid electrolyte layer; and the particle size of the non-metallic nanomaterials is less than 200 nm.

[0007] Secondly, the present invention provides a solid-state battery, which includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer, wherein the solid electrolyte layer is the solid electrolyte layer 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] In this invention, by introducing lithiophilic non-metallic nanomaterials into the solid electrolyte layer, excessive lithium dendrite growth can be effectively suppressed while maintaining good lithium-ion conductivity. The solid electrolyte layer exhibits excellent limiting current density. Solid-state batteries prepared using this solid electrolyte layer demonstrate good resistance to short-circuit failure, low self-discharge rate, and excellent cycle performance. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the solid-state battery obtained using the solid electrolyte layer in Examples 1-16.

[0014] Figure labels: 1-Positive electrode current collector, 2-Positive electrode material layer, 3-Solid electrolyte layer, 4-Non-metallic nanomaterial, 5-Lithium metal layer, 6-Negative electrode current collector.

[0015] Figure 2 This is a schematic diagram of the limiting current density test for a solid electrolyte layer. Detailed Implementation

[0016] 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.

[0017] solid electrolyte layer

[0018] The solid electrolyte layer provided in the first aspect of the present invention includes a solid electrolyte and non-metallic nanomaterials, wherein the non-metallic nanomaterials include one or more of boron nanomaterials, sulfur nanomaterials, selenium nanomaterials, red phosphorus nanomaterials and black phosphorus nanomaterials; the non-metallic nanomaterials account for 0.01 wt.% to 2 wt.% of the mass of the solid electrolyte layer; and the particle size of the non-metallic nanomaterials is less than 200 nm.

[0019] In this invention, by introducing non-metallic nanomaterials into the solid electrolyte layer, the solid electrolyte and non-metallic nanomaterials are uniformly mixed (in a non-coating form). This allows for the regulation of the current density distribution in the solid electrolyte during charging and discharging, increasing the limiting current density of the solid electrolyte layer and effectively mitigating the battery short-circuit problem caused by excessive lithium dendrite growth in the solid electrolyte layer. The aforementioned non-metallic nanomaterials function in several ways: First, during the charging and discharging process of a solid-state battery, the current density at the solid-solid interface between the solid electrolyte layer and the negative electrode layer is uneven. Lithium dendrites grow along the pores and grain boundaries between solid electrolyte particles. The non-metallic nanomaterials react with the lithium dendrites, eliminating them in the initial growth stage and thus inhibiting their growth. Second, after reacting with the lithium dendrites, the non-metallic nanomaterials can form fast ion conductors (such as Li₂Se and Li₃P), further enhancing the ionic conductivity of the solid electrolyte. This effectively regulates a more uniform distribution of the interfacial current density, thereby preventing the continued formation of lithium dendrites.

[0020] In some embodiments, the non-metallic nanomaterial is one or more of non-metallic nanoparticles, non-metallic nanosheets, non-metallic nanospheres, non-metallic nanoclusters, and non-metallic nanowires.

[0021] In some specific implementations, the non-metallic nanomaterial is selenium nanoparticles.

[0022] In some specific implementations, the non-metallic nanomaterial is black phosphorus nanosheets.

[0023] In some specific implementations, the non-metallic nanomaterial is red phosphorus nanosheets.

[0024] In some specific implementations, the non-metallic nanomaterial is boron nanoparticles.

[0025] In some specific implementations, the non-metallic nanomaterial is sulfur nanoparticles.

[0026] In some embodiments, the particle size of the non-metallic nanomaterial is 10-200 nm, for example, 10 nm, 50 nm, 100 nm, or 200 nm. The particle size of the non-metallic nanomaterial refers to the longest straight-line distance between any two points on the edge of the particle.

[0027] In some embodiments, the non-metallic nanomaterial accounts for 0.05 wt.% to 2 wt.% of the mass of the solid electrolyte layer, for example, 0.05 wt.%, 0.1 wt.%, 0.25 wt.%, 0.5 wt.%, 1 wt.% or 2 wt.%.

[0028] In some preferred embodiments, the non-metallic nanomaterial accounts for 0.1 wt.% to 1 wt.% of the mass of the solid electrolyte layer.

[0029] In some embodiments, the mass ratio of the non-metallic nanomaterial to the solid electrolyte is (0.01~10):(90~99.99), for example, 0.05:99.95, 0.05:99.85, 0.1:99.9, 0.25:99.75, 0.5:99.5, 1:99, 2:98 or 5:95.

[0030] In some preferred embodiments, the mass ratio of the non-metallic nanomaterial to the solid electrolyte is (0.1~1):(99~99.9).

[0031] In some embodiments, the thickness of the solid electrolyte layer is 10 to 1000 μm, for example, 100 μm.

[0032] In some embodiments, the non-metallic nanomaterials are uniformly distributed in a region extending from one surface of the solid electrolyte layer to half its thickness. In this invention, the current density of the solid electrolyte layer can be controlled by employing non-metallic nanomaterials. Considering that lithium dendrites typically begin to grow from the negative electrode side, by further concentrating and uniformly distributing the non-metallic nanomaterials in a region extending from one surface of the solid electrolyte layer to half its thickness, and then placing this region closer to the negative electrode layer during subsequent solid-state battery fabrication, the problem of uneven current density at the solid-solid interface between the solid electrolyte layer and the negative electrode layer during charging and discharging can be more effectively improved, further enhancing the cycle life of the resulting solid-state battery.

[0033] In some embodiments, the solid electrolyte accounts for 90 wt.% to 99.99 wt.% of the solid electrolyte layer by mass, for example, 99.95 wt.%, 99.85 wt.%, 99.90 wt.%, 99.75 wt.%, 99.50 wt.%, 99 wt.%, 98 wt.% or 95 wt.%.

[0034] In some embodiments, the particle size of the solid electrolyte is 100~4000 nm, for example, 800 nm or 870 nm. The particle size of the solid electrolyte refers to the longest straight-line distance between any two points on the edge of a solid electrolyte particle.

[0035] In this invention, the solid electrolyte can be a solid electrolyte conventionally used in the art.

[0036] In some embodiments, the solid electrolyte includes one or more of sulfide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

[0037] The sulfide solid electrolyte can be a conventionally used sulfide solid electrolyte in the art, preferably including Li3PS4, Li 10 GeP2S 12 and Li 10 SiP2S 12 One or more of them.

[0038] 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 formula, 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 the values ​​of a and b satisfy the principle of electroneutrality. For example, when b=6 and M is trivalent Y, a=3, and the molecular formula of the corresponding halide electrolyte is Li3YCl6. For example, when b=6 and M is trivalent In, a=3, and the compound is Li3InCl6.

[0039] The silver-germanium sulfide electrolyte preferably includes one or more of Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0040] The halide solid electrolyte preferably includes one or more of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3InCl6 and Li3YCl6.

[0041] The polymer solid electrolyte can be a polymer solid electrolyte conventionally used in the art, preferably including one or more of polyethylene oxide (PEO), polyacrylonitrile (PAN), polypropylene carbonate (PPC), and polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP).

[0042] In some preferred embodiments, the solid electrolyte includes Li3PS4, Li 10 GeP2S 12 Li 10 SiP2S 12 One or more of the following: Li3InCl6, Li3YCl6, Li6PS5Cl, Li6PS5Br, Li6PS5I, polyethylene oxide, polyacrylonitrile, polypropylene carbonate, and polyvinylidene fluoride-hexafluoropropylene copolymer.

[0043] In some specific embodiments, the solid electrolyte layer comprises Li3PS4 and selenium nanoparticles.

[0044] In some specific embodiments, the solid electrolyte layer comprises Li3PS4 and black phosphorus nanosheets.

[0045] In some specific embodiments, the solid electrolyte layer comprises Li3PS4 and red phosphorus nanosheets.

[0046] In some specific embodiments, the solid electrolyte layer comprises Li3PS4 and boron nanoparticles.

[0047] In some specific embodiments, the solid electrolyte layer comprises Li3PS4 and sulfur nanoparticles.

[0048] In some specific embodiments, the solid electrolyte layer comprises Li6PS5Cl and selenium nanoparticles.

[0049] In some specific embodiments, the solid electrolyte layer comprises polyethylene oxide and selenium nanoparticles.

[0050] In some embodiments, the solid electrolyte layer further includes a binder.

[0051] The adhesive may be an adhesive conventionally used in the art, preferably including one or more of styrene-butadiene rubber, nitrile rubber, polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), such as styrene-butadiene rubber.

[0052] The binder preferably accounts for less than 2 wt.% of the mass of the solid electrolyte layer, for example, 0.1 wt.%.

[0053] In some specific embodiments, the solid electrolyte layer includes Li3PS4, selenium nanoparticles, and styrene-butadiene rubber.

[0054] solid-state batteries

[0055] The solid-state battery provided in the second aspect of the present invention includes a positive electrode layer, a solid electrolyte layer and a negative electrode layer, wherein the solid electrolyte layer is a solid electrolyte layer as described above.

[0056] In some embodiments, the non-metallic nanomaterials are uniformly distributed in the solid electrolyte layer, extending from the surface of the solid electrolyte layer near the negative electrode layer to half its thickness. In this invention, the current density of the solid electrolyte layer can be controlled by employing non-metallic nanomaterials. Since lithium dendrites typically grow first from the negative electrode side, concentrating the non-metallic nanomaterials near the negative electrode layer during solid-state battery fabrication can more effectively improve the uneven current density at the solid-solid interface between the solid electrolyte layer and the negative electrode layer during charging and discharging, thereby further improving the cycle life of the resulting solid-state battery.

[0057] Positive electrode layer

[0058] In this invention, the positive electrode layer includes a positive electrode current collector and a positive electrode material layer disposed on at least one surface of the positive electrode current collector, wherein the positive electrode material layer includes a positive electrode material and a solid electrolyte.

[0059] In some implementations, the thickness of the positive electrode layer is 10 to 1000 μm, for example, 60 μm.

[0060] In this invention, the cathode material can be a cathode material conventionally used in the art, preferably including one or more of ternary cathode materials, phosphate cathode materials and spinel cathode materials.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] In this invention, the solid electrolyte can be a solid electrolyte conventionally used in the art, preferably including one or more of sulfide solid electrolytes, halide solid electrolytes and polymer solid electrolytes.

[0065] In some embodiments, the mass ratio of the positive electrode material to the solid electrolyte is (85~95):(5~10), for example, 90:8.

[0066] 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.

[0067] In some alternative implementations, the positive current collector is aluminum foil.

[0068] In some alternative embodiments, the thickness of the positive current collector can be 8 to 16 μm, for example 15 μm.

[0069] 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), acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal cracking black; conductive fibers such as carbon fibers and metal fibers; metal powders such as fluorinated carbon powder, aluminum powder, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; and conductive metal oxides or polyphenylene derivatives such as titanium dioxide, for example, conductive carbon black.

[0070] 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), 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 PVDF.

[0071] In some embodiments, the positive electrode material layer includes a positive electrode material, Li3PS4, and conductive carbon black.

[0072] In some specific implementations, the mass ratio of the cathode material, Li3PS4, and conductive carbon black is 90:8:2.

[0073] In this invention, the positive electrode layer can be prepared using methods conventional in the art.

[0074] In some alternative embodiments, the method for preparing the positive electrode layer includes the following steps:

[0075] The components of the positive electrode material layer are mixed evenly to obtain a mixture. The mixture is then coated on at least one surface of the positive electrode current collector and pressed into a sheet to obtain a positive electrode layer. The mixture forms the positive electrode material layer.

[0076] negative electrode layer

[0077] In some implementations, the thickness of the negative electrode layer is 0.1 to 200 μm, for example, 40 μm or 50 μm.

[0078] In some embodiments, the negative electrode layer 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.

[0079] In some embodiments, the negative electrode layer 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 including a negative electrode material.

[0080] 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.

[0081] 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.

[0082] In some implementations, the negative electrode material layer further includes a conductive agent.

[0083] 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.

[0084] In some implementations, the negative electrode material layer further includes a binder.

[0085] 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.

[0086] In some embodiments, the negative electrode material layer includes a negative electrode material and a binder.

[0087] 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.

[0088] In some embodiments, the method for preparing the negative electrode layer includes the following steps: mixing the components of the negative electrode material layer evenly to obtain a mixture; pressing the mixture into a sheet to obtain a negative electrode layer; wherein the mixture forms the negative electrode material layer.

[0089] In this invention, the solid-state battery can be prepared by conventional methods in the art, which may involve stacking a positive electrode layer and a solid electrolyte layer and pressing them together to form a solid battery, and then attaching a negative electrode layer to the surface of the solid electrolyte layer away from the positive electrode layer; or the positive electrode layer, the solid electrolyte layer and the negative electrode layer may be stacked sequentially and then pressed together to form the solid battery.

[0090] electronic devices

[0091] The electronic device provided in the third aspect of the present invention includes a solid-state battery as described above.

[0092] 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.

[0093] 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.

[0094] Example 1

[0095] Preparation of solid electrolyte layer: Li3PS4 electrolyte powder and selenium nanoparticles (particle size of 50nm) were mixed uniformly in a high-speed mixer at a mass ratio of 99.99:0.01, and then pre-pressed into a sheet (pressing pressure of 200MPa) to obtain a solid electrolyte layer (the mass percentage of selenium nanoparticles in the solid electrolyte layer is 0.01 wt.%, and the thickness is 100 μm).

[0096] Preparation of the positive electrode layer: using LiNi as the positive electrode material 0.9 Co 0.05 Mn 0.05 O2, Li3PS4, and Super P were mixed uniformly in a mass ratio of 90:8:2 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 of 200 MPa). The density of the positive electrode material was 18 mg / cm³. 2 The thickness of the positive electrode layer is 60 μm; the mixture forms the positive electrode material layer.

[0097] Solid-state battery fabrication: The pre-pressed positive electrode layer and solid electrolyte layer are pressed into shape under an isostatic pressure of 500 MPa (where the side of the positive electrode layer containing the positive electrode material is in close contact with the solid electrolyte layer). Then, a lithium-plated copper foil (with a lithium metal layer disposed on one surface of the copper foil, wherein 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 layer (where the lithium metal layer is in close contact with the solid electrolyte layer) and encapsulated.

[0098] Example 2

[0099] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 99.95:0.05. All other conditions and steps are the same as in Example 1.

[0100] Example 3

[0101] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 99.90:0.10. The remaining conditions and steps are the same as in Example 1.

[0102] Example 4

[0103] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 99.75:0.25. All other conditions and steps are the same as in Example 1.

[0104] Example 5

[0105] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 99.50:0.50. All other conditions and steps are the same as in Example 1.

[0106] Example 6

[0107] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 99.00:1.00. All other conditions and steps are the same as in Example 1.

[0108] Example 7

[0109] The difference between this embodiment and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 98.00:2.00. All other conditions and steps are the same as in Example 1.

[0110] Example 8

[0111] The difference between this embodiment and Embodiment 2 is that black phosphorus nanosheets (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. The remaining conditions and steps are the same as in Embodiment 2.

[0112] Example 9

[0113] The difference between this embodiment and Embodiment 2 is that red phosphorus nanosheets (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. The remaining conditions and steps are the same as in Embodiment 2.

[0114] Example 10

[0115] The difference between this embodiment and Embodiment 2 is that boron nanoparticles (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. All other conditions and steps are the same as in Embodiment 2.

[0116] Example 11

[0117] The difference between this embodiment and Embodiment 2 is that sulfur nanoparticles (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. All other conditions and steps are the same as in Embodiment 2.

[0118] Example 12

[0119] The difference between this embodiment and Embodiment 2 is that the size of the selenium nanoparticles in the solid electrolyte layer is 10 nm. The remaining conditions and steps are the same as in Embodiment 2.

[0120] Example 13

[0121] The difference between this embodiment and Embodiment 2 is that the size of the selenium nanoparticles in the solid electrolyte layer is 100 nm. The remaining conditions and steps are the same as in Embodiment 2.

[0122] Example 14

[0123] The difference between this embodiment and Embodiment 2 is that the size of the selenium nanoparticles in the solid electrolyte layer is 200 nm. The remaining conditions and steps are the same as in Embodiment 2.

[0124] Example 15

[0125] The difference between this embodiment and Embodiment 2 is that the Li3PS4 electrolyte is replaced with a halide electrolyte Li6PS5Cl in the solid electrolyte layer. All other conditions and steps are the same as in Embodiment 2.

[0126] Example 16

[0127] The difference between this embodiment and Embodiment 2 is that the Li3PS4 electrolyte is replaced with a polymer electrolyte PEO in the solid electrolyte layer. All other conditions and steps are the same as in Embodiment 2.

[0128] Example 17

[0129] The difference between this embodiment and Embodiment 2 is that a silicon-carbon electrode layer is used instead of lithium-plated copper foil in the solid-state battery.

[0130] The preparation of the silicon-carbon electrode layer: silicon-carbon material (BTR BSM-2) and PTFE are mixed evenly in a high-speed mixer at a mass ratio of 99:1, and then pressed onto a 10μm copper foil at 100MPa (the electrode thickness is 60 μm).

[0131] Solid-state battery fabrication: The positive electrode layer, 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.

[0132] The remaining conditions and steps are the same as in Example 2.

[0133] Example 18

[0134] The difference between this embodiment and Embodiment 2 is that the solid electrolyte layer is prepared by the following method: Li3PS4 electrolyte powder, selenium nanoparticles (particle size of 50nm) and styrene-butadiene rubber are mixed evenly in a high-speed mixer at a mass ratio of 99.85:0.05:0.1, and then pre-pressed into a sheet (pressing pressure of 200MPa) to obtain the solid electrolyte layer.

[0135] The remaining conditions and steps are the same as in Example 2.

[0136] Example 19

[0137] The difference between this embodiment and Embodiment 2 is that the solid electrolyte layer is prepared using the following method:

[0138] (1) Preparation of solid electrolyte layer A: The difference between the preparation of solid electrolyte layer A and the preparation of solid electrolyte layer A in Example 2 is that the thickness is halved (the amount of Li3PS4 electrolyte is halved), and it is pre-pressed at 100MPa pressure to obtain solid electrolyte layer A.

[0139] (2) Add half of the amount of Li3PS4 electrolyte (without selenium nanoparticles) to one surface of the solid electrolyte layer A along the thickness direction, and then pre-press it under a pressure of 200MPa to obtain the solid electrolyte layer;

[0140] In the resulting solid electrolyte layer, the non-metallic nanomaterials are uniformly distributed within a region of 1 / 2 the thickness of the solid electrolyte layer (solid electrolyte layer A). The total thickness of the solid electrolyte layer and the content of each component are the same as in Example 2.

[0141] The remaining conditions and steps are the same as in Example 2.

[0142] Schematic diagrams of the solid-state batteries obtained in Examples 1-16 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 5, and a negative electrode current collector 6; wherein, the solid electrolyte layer 3 contains non-metallic nanomaterials 4; wherein, the positive electrode current collector 1 and the positive electrode material layer 2 form the positive electrode layer of the solid-state battery, and the lithium metal layer 5 and the negative electrode current collector 6 form the negative electrode layer of the solid-state battery.

[0143] Comparative Example 1

[0144] The difference between this comparative example and Example 1 is that the solid electrolyte layer does not contain selenium nanoparticles (the total mass of the solid electrolyte layer remains unchanged). All other conditions and steps are the same as in Example 1.

[0145] Comparative Example 2

[0146] The difference between this comparative example and Example 2 is that Si nanoparticles (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. All other conditions and steps are the same as in Example 2.

[0147] Comparative Example 3

[0148] The difference between this comparative example and Example 2 is that Ag nanoparticles (50 nm in diameter) are used instead of selenium nanoparticles in the solid electrolyte layer. All other conditions and steps are the same as in Example 2.

[0149] Comparative Example 4

[0150] The difference between this comparative example and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 95.00:5.00. All other conditions and steps are the same as in Example 1.

[0151] Comparative Example 5

[0152] The difference between this comparative example and Example 1 is that the mass ratio of Li3PS4 electrolyte powder to selenium nanoparticles is 90.00:10.00. All other conditions and steps are the same as in Example 1.

[0153] Comparative Example 6

[0154] The difference between this comparative example and Example 2 is that the size of the selenium nanoparticles in the solid electrolyte layer is 500 nm. All other conditions and steps are the same as in Example 2.

[0155] Comparative Example 7

[0156] The difference between this comparative example and Example 2 is that the size of the selenium nanoparticles in the solid electrolyte layer is 600 nm. The remaining conditions and steps are the same as in Example 2.

[0157] Example 1

[0158] The particle size of the non-metallic nanomaterials and the solid electrolyte, the mass percentage of the non-metallic nanomaterials in the solid electrolyte, and the limiting current density of the solid electrolyte layer obtained in Examples 1-19 and Comparative Examples 1-7 were tested respectively. Specifically:

[0159] (1) Particle size of non-metallic nanomaterials

[0160] Scanning electron microscopy (ZEISS Sigma, equipped with an energy dispersive spectroscopy (EDS) accessory) was used to perform SEM measurements on the cross-sections of the solid electrolyte layers obtained in the examples and comparative examples, respectively, to obtain SEM images. The voltage was 5kV and the magnification was 5K. At least 200 particles were randomly selected from each SEM image (non-metallic nanomaterial particles could be distinguished by EDS testing). The particle size was measured using a nanometer (the maximum value of the longest straight-line distance between any two points on the edge of the particle). SEM measurements were performed on each sample to obtain 3 SEM images, and the particle size of at least 600 particles was measured. The average value was taken to obtain the particle size.

[0161] The test results are shown in Table 1.

[0162] (2) Particle size of solid electrolyte

[0163] The cross-sections of the solid electrolyte layers obtained in the examples and comparative examples were measured using a scanning electron microscope (ZEISS Sigma, equipped with EDS accessory). 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 (solid electrolyte particles can be distinguished by EDS test). The particle size was measured using a Nanomeasurer (the maximum value of the longest straight-line distance between any two points on the edge of the particle). SEM tests were performed on each sample to obtain 3 SEM images, and the particle size of at least 600 particles was measured. The average value was taken to obtain the particle size.

[0164] (3) Mass percentage of non-metallic nanomaterials in solid electrolyte

[0165] The cross-sections of the solid electrolyte layers obtained in the examples and comparative examples were tested by scanning electron microscopy (ZEISS Sigma, equipped with EDS accessory) (voltage 5kV, magnification 5K) to obtain the mass percentage of non-metallic nanomaterials in the solid electrolyte.

[0166] The test results are shown in Table 1.

[0167] (3) Testing of the limiting current density of the solid electrolyte layer

[0168] A lithium-lithium symmetric battery was assembled by placing a solid electrolyte layer between two lithium metal sheets. The battery was subjected to constant current charge and discharge for 1 hour, followed by sequential charging and discharging at 0.05 mA / cm². 2 The current density is increased by a gradient (the initial current density is 0.1 mA / cm²). 2When the voltage suddenly drops, it indicates that the dendrites have pierced the solid electrolyte layer. The current density at this time is the limiting current density. This index can characterize the ability of the solid electrolyte layer to withstand dendrite short circuits. The higher the limiting current density, the stronger the ability of the solid electrolyte layer to resist lithium dendrite piercing.

[0169] A schematic diagram of the limiting current density test of the above solid electrolyte layer is shown below. Figure 2 As shown.

[0170] The test results are shown in Table 2.

[0171] Example 2

[0172] The solid-state batteries in Examples 1-19 and Comparative Examples 1-7 were tested for cycle performance and self-discharge rate, respectively. Specifically:

[0173] (1) Cyclic performance test

[0174] The solid-state batteries from Examples 1-19 and Comparative Examples 1-7 were used to test their cycle performance. Specifically:

[0175] During the test, a pressure of 10 MPa was applied to the newly prepared battery to ensure good interface contact. The battery was activated by cycling twice at 2.5~4.25V, room temperature (25℃), 0.1C charging, and 0.1C discharging rate. After activation, cycle performance testing was performed. Specifically, the battery was cycled at 2.5~4.25V, room temperature, 1C charging, and 1C discharging rate (1C=200 mA / g) until the ratio of the discharge capacity of the nth cycle to the discharge capacity of the first 1C cycle 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, which is the EOL (End of Life) life. The test results are shown in Table 2.

[0176] (2) Self-discharge rate test

[0177] The newly prepared solid-state battery was cycled 3 times under the following conditions: constant current charging at 0.33C to 4.25V, then constant voltage charging, current cutoff at 0.05C (full charge), and discharge at 0.33C to 2.5V. The discharge capacity at this point was recorded as C0. The battery was then fully charged and stored at 30℃ for 7 days. After 7 days, the remaining capacity was measured by discharge testing, and the value was recorded as C1. The self-discharge rate was calculated based on C0 and C1 using the formula: Self-discharge rate = (1 - C1 / C0) × 100%. The test results are shown in Table 2.

[0178] Table 1

[0179]

[0180] Note: In Table 1, " / " indicates that the condition parameter is not involved in the specific experiment.

[0181] Table 2

[0182]

[0183] The solid electrolyte layer comprising non-metallic nanomaterials (boron nanomaterials, sulfur nanomaterials, selenium nanomaterials, red phosphorus nanomaterials, and black phosphorus nanomaterials) used in Examples 1-19 of this invention exhibits excellent limiting current density, reaching 0.35 mA / cm². 2 In conclusion, the solid-state battery obtained using this solid electrolyte layer exhibits excellent cycle performance and a low self-discharge rate. Specifically, the self-discharge rate of the solid-state battery can reach below 8.6%, while also ensuring an end-of-life (EOL) of over 180 cycles.

[0184] Compared to Example 1, Comparative Example 1 did not include selenium nanoparticles, resulting in a poorer self-discharge rate and a significantly reduced cycle life for the resulting solid-state battery.

[0185] The inventors discovered that only solid-state batteries obtained by using a solid electrolyte layer made of specific types of non-metallic nanomaterials (boron nanomaterials, sulfur nanomaterials, selenium nanomaterials, red phosphorus nanomaterials, and black phosphorus nanomaterials) can achieve low self-discharge rates and excellent cycle life. Other types of non-metallic nanomaterials, such as Si nanoparticles, cannot achieve the aforementioned superior effects. In Comparative Example 2, Si nanoparticles were used instead of selenium nanoparticles, and compared to Example 2, the self-discharge rate and cycle life of the resulting solid-state battery were significantly worse.

[0186] Compared with Example 2, Comparative Example 3 used Ag nanoparticles to replace selenium nanoparticles. Although the resulting solid-state battery had a better cycle life, the self-discharge rate increased significantly and the battery performance deteriorated significantly.

[0187] The percentage of non-metallic nanomaterials in the solid electrolyte layer affects the performance of solid-state batteries. In Comparative Examples 4 and 5, the percentage of non-metallic nanomaterials in the solid electrolyte was too high, resulting in significantly lower cycle life (EOL) of the resulting solid-state batteries. As can be seen from Examples 2-7, by further adjusting the percentage of non-metallic nanomaterials in the solid electrolyte layer to between 0.05 wt.% and 2 wt.%, the cycle life of the resulting solid-state batteries was further improved, reaching over 245 cycles.

[0188] Furthermore, the particle size of non-metallic nanomaterials is also a crucial parameter affecting the performance of solid-state batteries. In Comparative Examples 6 and 7, the particle size of the non-metallic nanomaterials was too large, resulting in a significantly lower limiting current density of the solid electrolyte layer and a substantial decrease in the EOL (End-of-Life) life of the resulting solid-state batteries. As can be seen from Examples 1 and 12-14, by controlling the particle size of the non-metallic nanomaterials to below 200 nm in this invention, the solid electrolyte layer exhibits excellent limiting current density, and the resulting solid-state batteries all demonstrate excellent cycle life and low self-discharge rate.

[0189] 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 electrolyte layer, characterized in that, It includes a solid electrolyte and non-metallic nanomaterials, wherein the non-metallic nanomaterials include one or more of boron nanomaterials, sulfur nanomaterials, selenium nanomaterials, red phosphorus nanomaterials and black phosphorus nanomaterials; the non-metallic nanomaterials account for 0.01 wt.% to 2 wt.% of the mass of the solid electrolyte layer; and the particle size of the non-metallic nanomaterials is less than 200 nm.

2. The solid electrolyte layer according to claim 1, characterized in that, The non-metallic nanomaterials satisfy one or more of the following conditions a to d: a. The non-metallic nanomaterial is one or more of the following: non-metallic nanoparticles, non-metallic nanosheets, non-metallic nanospheres, non-metallic nanoclusters, and non-metallic nanowires; b. The particle size of the non-metallic nanomaterial is 10~200 nm; c. The non-metallic nanomaterials constitute 0.05 wt.% to 2 wt.% of the mass of the solid electrolyte layer. d. The mass ratio of the non-metallic nanomaterial to the solid electrolyte is (0.01~10):(90~99.99).

3. The solid electrolyte layer according to claim 1, characterized in that, The solid electrolyte satisfies one or both of the following conditions a to b: a. The particle size of the solid electrolyte is 100~4000 nm; b. The solid electrolyte includes one or more of sulfide solid electrolytes, halide solid electrolytes, and polymer solid electrolytes.

4. The solid electrolyte layer according to claim 3, characterized in that, The solid electrolyte satisfies one or more of the following conditions a to c: a. The sulfide solid electrolyte includes Li3PS4, Li 10 GeP2S 12 and Li 10 SiP2S 12 One or more of the following; b. The halide solid electrolyte includes one or more of Li6PS5Cl, Li6PS5Br, Li6PS5I, Li3InCl6 and Li3YCl6; c. The polymer-based solid electrolyte includes one or more of polyethylene oxide, polyacrylonitrile, polypropylene carbonate, and polyvinylidene fluoride-hexafluoropropylene copolymer.

5. The solid electrolyte layer according to claim 1, characterized in that, The solid electrolyte layer satisfies any one of the following conditions a to g: a. The solid electrolyte layer comprises Li3PS4 and selenium nanoparticles; b. The solid electrolyte layer comprises Li3PS4 and black phosphorus nanosheets; c. The solid electrolyte layer comprises Li3PS4 and red phosphorus nanosheets; d. The solid electrolyte layer comprises Li3PS4 and boron nanoparticles; e. The solid electrolyte layer comprises Li3PS4 and sulfur nanoparticles; f. The solid electrolyte layer comprises Li6PS5Cl and selenium nanoparticles; g. The solid electrolyte layer comprises polyethylene oxide and selenium nanoparticles.

6. The solid electrolyte layer according to claim 1, characterized in that, The solid electrolyte layer satisfies one or both of the following conditions a to b: a. The thickness of the solid electrolyte layer is 10~1000 μm; b. The non-metallic nanomaterials are uniformly distributed in a region from one surface of the solid electrolyte layer to half its thickness.

7. The solid electrolyte layer according to claim 1, characterized in that, The solid electrolyte layer also includes a binder.

8. A solid-state battery, comprising a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, characterized in that, The solid electrolyte layer is the solid electrolyte layer as described in any one of claims 1 to 7.

9. The solid-state battery according to claim 8, characterized in that, In the solid electrolyte layer, the non-metallic nanomaterials are uniformly distributed in a region from the surface of the solid electrolyte layer near the negative electrode layer to half the thickness.

10. An electronic device, characterized in that, It includes the solid-state battery as described in claim 8 or 9.

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