Positive electrode sheet and manufacturing method therefor, battery, and electric device

Abstract

To solve the problem of limited ion conduction in existing thick electrodes, a positive electrode sheet and a manufacturing method therefor, a battery, and an electric device are provided. The positive electrode sheet comprises a current collector and an active material layer, the active material layer being arranged on at least one side of the current collector. The active material layer comprises a positive electrode active material, an electronic conductive agent, an ionic conductive agent, and an additive; and a particle size ratio of the positive electrode active material to the ionic conductive agent ranges from (1:1) to (1:0.05).

Description

A positive electrode sheet and its preparation method, a battery, and an electrical device thereof.

[0001] This application claims priority to Chinese Patent Application No. 202410692688.8, filed on May 30, 2024, entitled "A positive electrode sheet and its preparation method, battery, and power device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of battery technology, specifically relating to a positive electrode sheet and its preparation method, a battery, and an electrical device. Background Technology

[0003] Batteries, such as high-energy-density lithium-ion batteries, have significant applications in various fields, including electric vehicles, portable electronic devices, and energy storage systems. One key strategy for improving the energy density of lithium-ion batteries is to increase the thickness of the positive electrode. A thicker positive electrode can store more active material within a limited battery volume and weight, thus significantly improving the battery's energy density. Regardless of the type of negative electrode material used, such as lithium metal, graphite, silicon-carbon composites, or alloys, the application of a thicker positive electrode can effectively improve battery performance. However, in traditional electrode structures, increasing the electrode thickness leads to a proportional increase in the charge (electron and ion) transport distance and resistance. Adding a solid electrolyte to the electrode can improve ion conduction performance, but the high point contact impedance between the electrode and electrolyte materials cannot effectively solve the ion conduction problem. The charge transport kinetics of thick electrodes are poor, requiring more time for lithium ions to reach all storage sites within the electrode to prevent lithium plating, ultimately leading to deterioration in rate performance and hindering energy density improvement. Summary of the Invention

[0004] To address the problem of limited ion conduction in existing thick electrodes, this application provides a positive electrode sheet, its preparation method, a battery, and an electrical device.

[0005] The technical solution adopted in this application to solve the above-mentioned technical problems is as follows:

[0006] In a first aspect, this application provides a positive electrode sheet, including a current collector and an active material layer, wherein the active material layer is disposed on at least one side of the current collector; the active material layer includes a positive electrode active material, an electronic conductive agent, an ionic conductive agent and an additive, wherein the particle size ratio of the positive electrode active material to the ionic conductive agent is (1:1)-(1:0.05).

[0007] Optionally, the particle size of the positive electrode active material is 0.2 μm-30 μm, and the particle size of the ionic conductive agent is 0.01 μm-30 μm.

[0008] Optionally, the ionic conductive agent comprises a halide solid electrolyte, which comprises a compound shown in Formula 1, Li a (M b )X c Formula 1

[0009] M includes one or more of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, and lanthanide metals.

[0010] X includes one or more of the halogen elements;

[0011] 0.5≤a≤6, 0.2≤b≤4, c=a+bε, where ε is the weighted average valence of M.

[0012] Optionally, the halide solid electrolyte includes LiAlF4, Li3YCl6, Li3InCl6, and Li3InCl. 5.5 F 0.5 Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 One or more of Cl3.

[0013] Optionally, the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium iron manganese phosphate, lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium-rich manganese-based oxide, lithium nickel manganese oxide, and lithium vanadium oxide phosphate.

[0014] Optionally, the electronically conductive agent includes one or more of graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, and furnace black.

[0015] Optionally, the additives include one or more of the following: polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, styrene-butadiene rubber, hydrogenated nitrile rubber, boronized polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose, cellulose salt derivatives, polyacrylic acid, polyamide, polyvinyl alcohol, polyethyleneimine, and polyimide.

[0016] Optionally, based on the content of the active material layer being 100%, the mass content of the ionic conductive agent is 5%-50%, the mass content of the electronic conductive agent is 0.05%-5%, and the mass content of the auxiliary agent is 0.1%-10%.

[0017] Optionally, the current collector is selected from aluminum metal current collectors or composite current collectors, wherein the composite current collector includes a base film and conductive layers disposed on both sides of the base film.

[0018] Optionally, the base film includes one or more of polyethylene, polyethylene terephthalate, polyimide, polypropylene, polyethylene, polyamide, and polyphenylene sulfide; the conductive layer includes an aluminum layer.

[0019] Optionally, the thickness of the positive electrode sheet is 20 μm to 6 mm;

[0020] The thickness of the base film is 1-300 μm, and the thickness of the conductive layer is 0.5-100 μm.

[0021] Optionally, an adhesive layer is provided between the active material layer and the current collector. The adhesive layer includes a conductive adhesive and a conductive filler. The conductive adhesive includes epoxy resin, and the conductive filler includes one or more of silver, nickel, copper, aluminum, carbon black, graphite, carbon nanotubes, graphene, and silver-modified carbon nanotubes.

[0022] Secondly, this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0023] The positive electrode active material, ionic conductive agent, electronic conductive agent, additives, and dispersant are mixed to obtain a slurry;

[0024] The slurry is coated onto the current collector and dried to obtain a positive electrode sheet.

[0025] Optionally, the dispersant includes one or more of toluene, acetonitrile, 1-hexene, diethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dimethyl sulfoxide.

[0026] Thirdly, this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0027] The positive electrode active material, ionic conductive agent, electronic conductive agent and additives are mixed to obtain a mixed powder;

[0028] Shear force is applied to the mixed powder to fiberize the additives, thereby obtaining a preform;

[0029] The preform is extruded or rolled into a self-supporting film, the self-supporting film is combined with the current collector, and then rolled to form a positive electrode sheet.

[0030] Optionally, applying shear force to the mixed powder includes stirring the mixed powder at a speed of 500-3000 rpm for a time of 10-60 min.

[0031] Optionally, the additive is selected from polytetrafluoroethylene (PTFE), wherein the PTFE has a molecular weight of 10. 6 -10 8 g / mol.

[0032] Optionally, the temperature of the roller pressing is 60-200℃.

[0033] Fourthly, this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0034] The positive electrode active material, ionic conductive agent, electronic conductive agent and additives are mixed to obtain a mixed powder;

[0035] The mixed powder is sprayed onto the current collector, and the current collector carrying the mixed powder is hot-pressed to obtain a positive electrode sheet.

[0036] Optionally, the spraying method for applying the mixed powder to the current collector is electrostatic powder spraying. The conditions for electrostatic powder spraying include: a charging voltage of 15-90kV, a carrier gas pressure of 10-100psi, an auxiliary gas selected from argon, and a gap distance of 2-30cm between the spray gun head and the current collector.

[0037] Optionally, the hot pressing is hot roller pressing, and the temperature of the hot roller pressing is 60-200℃.

[0038] Fourthly, this application provides a battery, which is a solid-state battery or a semi-solid-state battery, comprising a negative electrode, a solid electrolyte, and a positive electrode sheet as described in any of the above.

[0039] Alternatively, the solid-state battery or semi-solid-state battery may include a positive electrode prepared by the method described above.

[0040] Optionally, the solid electrolyte includes one or more of the following: halide solid electrolyte, sulfide solid electrolyte, oxide solid electrolyte, polymer solid electrolyte, and composite solid electrolyte;

[0041] The negative electrode is selected from lithium metal, lithium alloy, graphite negative electrode, silicon-oxygen negative electrode, silicon-carbon negative electrode, silicon negative electrode, tin negative electrode, tin oxide negative electrode, and tin alloy negative electrode. The lithium alloy includes an alloy formed by lithium with one or more of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, and phosphorus.

[0042] Alternatively, the negative electrode may be selected from lithium-free negative electrodes.

[0043] Optionally, the halide solid electrolyte includes one or more of Li3YCl6, Li3ScCl6, and Li3YBr6;

[0044] The sulfide solid electrolyte includes one or more of LGPS, LPS, and LPSCl;

[0045] The oxide solid electrolyte includes one or more of LLZO, LLZTO, LLTO, LATP, and LAGP;

[0046] The polymer solid electrolyte includes one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0047] The composite solid electrolyte comprises an inorganic filler and a polymer matrix. The inorganic filler comprises one or more of oxide solid electrolytes, sulfide solid electrolytes, and halide solid electrolytes. The polymer matrix comprises one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0048] Fifthly, this application provides an electrical device including a battery as described in any of the above claims. Beneficial effects

[0049] In the positive electrode, by controlling the particle size ratio of the positive electrode active material and the ion-conducting agent, the ion-conducting agent is facilitated to distribute evenly within the positive electrode, forming a network structure. This effectively increases the ion conduction pathways, significantly improving the electrode's ion conductivity and thus enhancing the overall battery performance. The network structure formed by the ion-conducting agent in the positive electrode ensures efficient ion transport even in thicker electrodes.

[0050] In the preparation method of positive electrode, the reaction between halide solid electrolyte and organic solvent in positive electrode prepared by using dispersants or dry preparation process is avoided, which is the case in the traditional wet preparation method. Detailed Implementation

[0051] To make the technical problems, technical solutions, and beneficial effects solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0052] One embodiment of this application provides a positive electrode sheet, including a current collector and an active material layer, wherein the active material layer is disposed on at least one side of the current collector; the active material layer includes a positive electrode active material, an electronic conductive agent, an ionic conductive agent and an additive, wherein the particle size ratio of the positive electrode active material to the ionic conductive agent is (1:1)-(1:0.05).

[0053] Specifically, the particle size ratio of the positive electrode active material to the ionic conductive agent can be 1:0.05, 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:0.9 or 1:1.

[0054] In this application, by controlling the particle size ratio of the positive electrode active material and the ion-conducting agent, the uniform distribution of the ion-conducting agent in the positive electrode sheet is facilitated, enabling the ion-conducting agent to form a network structure in the positive electrode sheet. This effectively increases the ion conduction path and improves the ion conductivity of the electrode, thereby enhancing the overall performance of the battery. The network structure formed by the ion-conducting agent in the positive electrode sheet ensures efficient ion transport even in thicker electrodes.

[0055] In some embodiments, the particle size of the positive electrode active material is 0.2 μm-30 μm, and the particle size of the ionic conductive agent is 0.01 μm-30 μm.

[0056] Specifically, the particle size of the positive electrode active material can be 0.2 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 1.5 μm, 5 μm, 8 μm, 10 μm, 12 μm, 20 μm, or 30 μm. The particle size of the ion-conducting agent can be 0.01 μm, 0.1 μm, 0.25 μm, 0.4 μm, 0.5 μm, 0.8 μm, 1 μm, 5 μm, 8 μm, 10 μm, 13 μm, 16 μm, 19 μm, 22 μm, 25 μm, 28 μm, or 30 μm. In some embodiments, the ion-conducting agent comprises a halide solid electrolyte, which comprises a compound of Formula 1, Li a (M b )X c Formula 1

[0057] M includes one or more of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, and lanthanide metals.

[0058] X includes one or more of the halogen elements;

[0059] 0.5≤a≤6, 0.2≤b≤4, c=a+bε, where ε is the weighted average valence of M.

[0060] In some embodiments, the halide solid electrolyte includes LiAlF4, Li3YCl6, Li3InCl6, and Li3InCl. 5.5 F 0.5 Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 One or more of Cl3.

[0061] In some embodiments, the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium iron manganese phosphate, lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium-rich manganese-based oxide, lithium nickel manganese oxide, and lithium vanadium oxide phosphate.

[0062] In one specific embodiment, the positive electrode active material includes LiFePO4 and LiFe x Mn y PO4(x+y=1), LVPO(Li3V2(PO4)3, LiVOPO4), NCA(LiNi 0.92 Mn 0.04 Co 0.04 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2, LiNi 0.75 Mn 0.1 Co 0.15 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.33 Mn 0.33 Co 0.33 O2), LiCoO2, LiNiO2, LiMn2O4, LiNi 0.5 Mn 1.5 O, Li 1.2 Ni 0.2 Mn 0.6 O2, Li 1.2 Co 0.4 Mn 0.4 O2、x'Li2MnO3·(1-x')LiNi 0.5 Mn 1.5 O4, 0.05≤x'≤0.95, x”Li2MnO3·(1-x”)LiNi a Co b Mn c One or more of the following: O2, 0.05≤x”≤0.95, 0≤b≤0.5, a+b+c=1.

[0063] In some embodiments, the electronically conductive agent includes one or more of graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, and furnace black.

[0064] In some embodiments, the additives include one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), silicone rubber, styrene-butadiene rubber (SBR), hydrogenated nitrile butadiene rubber (HNBR), boronized polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose, cellulose salt derivatives, polyacrylic acid (PAA), polyamide (PAI), polyvinyl alcohol (PVA), polyethyleneimine (PEI), and polyimide (PI).

[0065] In some embodiments, based on the content of the active material layer being 100%, the mass content of the ionic conductive agent is 5%-50%, the mass content of the electronic conductive agent is 0.05%-5%, and the mass content of the auxiliary agent is 0.1%-10%.

[0066] Specifically, the mass content of the ionic conductive agent can be 5%, 8%, 11%, 14%, 17%, 20%, 23%, 26%, 29%, 32%, 35%, 38%, 41%, 44%, 47%, or 50%. The mass content of the electronic conductive agent can be 0.05%, 0.1%, 0.4%, 0.7%, 1.0%, 1.3%, 1.7%, 2.0%, 2.3%, 2.6%, 2.9%, 3.0%, 3.3%, 3.6%, 3.9%, 4.2%, 4.5%, 4.8%, or 5%. The mass content of the auxiliary agent can be 0.1%, 0.4%, 0.7%, 1.0%, 2.0%, 2.6%, 5.0%, 6.3%, 7.6%, 8.9%, or 10.0%.

[0067] In a preferred embodiment, with the content of the active material layer being 100%, the mass content of the ionic conductive agent is 10%-25%, the mass content of the electronic conductive agent is 1%-3%, and the mass content of the auxiliary agent is 1%-3%.

[0068] In some embodiments, the current collector is selected from aluminum metal current collectors or composite current collectors, wherein the composite current collector includes a base film and conductive layers disposed on both sides of the base film.

[0069] In some embodiments, the base film comprises one or more of polyethylene, polyethylene terephthalate, polyimide, polypropylene, polyethylene, polyamide, and polyphenylene sulfide; the conductive layer comprises an aluminum layer. Specifically, the base film can be a single-layer film or a composite film of different materials.

[0070] In some embodiments, the thickness of the positive electrode sheet is 20 μm to 6 mm, and the lithium battery has high energy density by preparing a thick electrode structure.

[0071] The thickness of the base film is 1-300 μm, and the thickness of the conductive layer is 0.5-100 μm.

[0072] In some embodiments, an adhesive layer is provided between the active material layer and the current collector. The adhesive layer includes a conductive adhesive and a conductive filler. The conductive adhesive includes epoxy resin, and the conductive filler includes one or more of silver, nickel, copper, aluminum, carbon black, graphite, carbon nanotubes, graphene, and silver-modified carbon nanotubes.

[0073] One embodiment of this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0074] The positive electrode active material, ionic conductive agent, electronic conductive agent, additives, and dispersant are mixed to obtain a slurry;

[0075] The slurry is coated onto the current collector and dried to obtain a positive electrode sheet.

[0076] In some embodiments, the dispersant includes one or more of toluene, acetonitrile, 1-hexene, diethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dimethyl sulfoxide.

[0077] By using a solvent that is chemically compatible with the halide solid electrolyte to prepare the composite cathode, the reaction between the halide solid electrolyte and the organic solvent in the traditional wet-process cathode sheet is avoided.

[0078] An alternative embodiment of this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0079] The positive electrode active material, ionic conductive agent, electronic conductive agent and additives are mixed to obtain a mixed powder;

[0080] Shear force is applied to the mixed powder to fiberize the additives and obtain a preform; specifically, the shear force is applied by means including but not limited to high-speed stirring, screw extrusion or air jet milling.

[0081] The preform is extruded or rolled into a self-supporting film, which is then composited with the current collector and rolled to form a positive electrode sheet. This dry preparation process avoids the reaction between the halide solid electrolyte and the organic solvent, which is present in traditional wet-process positive electrode sheets.

[0082] In some embodiments, applying shear force to the mixed powder includes stirring the mixed powder at a speed of 500-3000 rpm for a time of 10-60 min.

[0083] In some embodiments, the additive is selected from polytetrafluoroethylene (PTFE), wherein the PTFE has a molecular weight of 10. 6 -10 8 g / mol.

[0084] In some embodiments, the temperature of the rolling process is 60-200°C.

[0085] An alternative embodiment of this application provides a method for preparing a positive electrode sheet as described in any of the above claims, comprising the following steps:

[0086] The positive electrode active material, ionic conductive agent, electronic conductive agent and additives are mixed to obtain a mixed powder;

[0087] The mixed powder is sprayed onto the current collector, and the current collector carrying the mixed powder is hot-pressed to obtain a positive electrode sheet. This dry preparation process avoids the reaction between the halide solid electrolyte and the organic solvent, which is present in traditional wet-process positive electrode sheets.

[0088] In some embodiments, the spraying method for applying the mixed powder to the current collector is electrostatic powder spraying. The conditions for electrostatic powder spraying include: a charging voltage of 15-90kV, a carrier gas pressure of 10-100psi, an auxiliary gas selected from argon, and a gap distance of 2-30cm between the spray gun head and the current collector.

[0089] In some embodiments, the hot pressing is hot roller pressing, and the temperature of the hot roller pressing is 60-200°C.

[0090] One embodiment of this application provides a battery, which is a solid-state battery or a semi-solid-state battery. The solid-state battery or semi-solid-state battery includes a negative electrode, a solid electrolyte, and a positive electrode sheet as described in any of the above embodiments.

[0091] Alternatively, the solid-state battery or semi-solid-state battery may include a positive electrode prepared by the method described above.

[0092] In some embodiments, the solid electrolyte includes one or more of halide solid electrolytes, sulfide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, and composite solid electrolytes;

[0093] The negative electrode is selected from lithium metal, lithium alloy, graphite negative electrode, silicon-oxygen negative electrode, silicon-carbon negative electrode, silicon negative electrode, tin negative electrode, tin oxide negative electrode, and tin alloy negative electrode. The lithium alloy includes an alloy formed by lithium with one or more of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, and phosphorus.

[0094] Tin alloy anodes include, but are not limited to, Sn-Fe, Sn-Co, and Sn-Cu.

[0095] Alternatively, the negative electrode may be selected from lithium-free negative electrodes.

[0096] In some embodiments, the halide solid electrolyte includes one or more of Li3YCl6, Li3ScCl6, and Li3YBr6;

[0097] The sulfide solid electrolyte includes one or more of LGPS, LPS, and LPSCl;

[0098] The oxide solid electrolyte includes one or more of LLZO, LLZTO, LLTO, LATP, and LAGP;

[0099] The polymer solid electrolyte includes one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0100] The composite solid electrolyte comprises an inorganic filler and a polymer matrix. The inorganic filler comprises one or more of oxide solid electrolytes, sulfide solid electrolytes, and halide solid electrolytes. The polymer matrix comprises one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0101] One embodiment of this application also provides an electrical device, including a battery as described in any of the above embodiments.

[0102] The present application will be further illustrated by the following examples.

[0103] Example 1

[0104] This embodiment illustrates the positive electrode sheet and battery disclosed in this application, and includes the following operation steps:

[0105] Positive electrode preparation:

[0106] Lithium nickel cobalt manganese oxide (LCM), ion-conducting agent Li3YCl6, electronically conductive agents (carbon nanotubes, graphene, porous carbon), polytetrafluoroethylene (PTFE), and dispersant (toluene) were mixed and dispersed uniformly at a mass ratio of 83:15:1:1:150 to obtain a positive electrode slurry. The positive electrode slurry was coated onto aluminum foil, dried, and then compacted using a roller press to obtain a usable positive electrode sheet. The particle size of LCM was 12 μm, the particle size of Li3YCl6 was 5 μm, and the particle size ratio of the positive electrode active material to the ion-conducting agent was 12:5.

[0107] Negative electrode plate:

[0108] Using lithium metal as the negative electrode, the test disc of lithium metal was conducted using a coin cell as the negative electrode.

[0109] Solid electrolyte:

[0110] The solid electrolyte is Li3Yb 0.8 Zr 0.2 Cl 6.2 The preparation method is as follows: LiCl, YbCl3, and ZrCl4 are used as raw materials, wherein the molar ratio of LiCl, InCl3, and ZnCl2 is 3:0.8:0.2. The raw materials LiCl and YbCl3 are mixed and ball-milled once to obtain a solid electrolyte precursor. ZnCl2 is added to the solid electrolyte precursor and ball-milled a second time to obtain the solid electrolyte material Li3Yb. 0.8 Zr 0.2 Cl 6.2 .

[0111] Battery fabrication:

[0112] The positive electrode, negative electrode, solid electrolyte, and casing prepared above are assembled into a lithium metal solid-state battery.

[0113] Example 2

[0114] This embodiment is used to illustrate the positive electrode sheet and battery disclosed in this application, including most of the operating steps in Embodiment 1, with the following differences:

[0115] Positive electrode preparation:

[0116] The positive electrode active material lithium nickel cobalt manganese oxide, the ion conductive agent Li3YCl6, the electronic conductive agent (carbon nanotubes, graphene, porous carbon), and polytetrafluoroethylene were mixed in a mass ratio of 80:15:2:3 and dispersed evenly to obtain a mixed powder.

[0117] The mixed powder was stirred at 2800 rpm for 50 min to fiberize the polytetrafluoroethylene and obtain a preform.

[0118] The preform is extruded into a self-supporting film, and the self-supporting film is composited with the aluminum foil and rolled at 120°C to form a positive electrode sheet.

[0119] Example 3

[0120] This embodiment is used to illustrate the positive electrode sheet and battery disclosed in this application, including most of the operating steps in Embodiment 1, with the following differences:

[0121] Positive electrode preparation:

[0122] The positive electrode active material lithium nickel cobalt manganese oxide, the ion conductive agent Li3YCl6, the electronic conductive agent (carbon nanotubes, graphene, porous carbon), and polytetrafluoroethylene were mixed in a mass ratio of 70:25:2:3 and dispersed evenly to obtain a mixed powder.

[0123] The mixed powder was sprayed onto the aluminum foil under the conditions of a charging voltage of 15kV, a carrier gas pressure of 10psi, and a gap distance of 5cm between the spray gun head and the aluminum foil.

[0124] Aluminum foil coated with mixed powder is rolled at 120°C to form a positive electrode sheet.

[0125] Example 4-25

[0126] Examples 4-25 illustrate the positive electrode sheet and battery disclosed in this application, including most of the operating steps in Example 2, except that the formulation in Table 1 is used.

[0127] Comparative Examples 1-3

[0128] The comparative examples are used to illustrate the positive electrode and battery disclosed in this application, including most of the operating steps in Example 2, except that the formulation in Table 1 is used.

[0129] Table 1

[0130] Performance testing

[0131] Cyclic performance test:

[0132] The positive electrode sheets of the examples and comparative examples were assembled into batteries, and the battery cycle capacity retention rate was tested by 200 cycles of 1C / 1C charge and discharge at room temperature of 25°C.

[0133] Table 2

[0134] As shown in Table 2, the test results of the examples and comparative examples reveal that as the particle size ratio of the positive electrode active material to the ionic conductive agent decreases, the specific discharge capacity of the positive electrode in the first cycle increases. However, when the particle size ratio of the positive electrode active material to the ionic conductive agent is too low, the specific discharge capacity decreases. Furthermore, when the particle size ratio remains constant, but the particle sizes of both the positive electrode active material and the ionic conductive agent increase, the specific discharge capacity decreases. This demonstrates that by controlling the particle size and particle size ratio of the positive electrode active material and the ionic conductive agent, the ionic conductive agent can be evenly distributed in the positive electrode, forming a network structure and increasing the ion conduction path, effectively improving the ion conductivity of the electrode and thus enhancing the overall performance of the battery.

[0135] The test results of Examples 2, 3, and 8-11 show that the specific capacity of the positive electrode in the first discharge cycle increases with the increase of the ionic conductive agent content. However, when the ionic conductive agent content is too high, the specific capacity does not continue to increase and saturation may occur. For example, in Example 10, the ionic conductive agent content reached 60%, but compared with 35% in Example 8, the specific capacity did not increase.

[0136] The test results from Examples 2 and 12-15 show that the specific capacity of the positive electrode in the first discharge cycle is affected by the content of the electronically conductive agent. When the content of the electronically conductive agent increases, the specific capacity of the positive electrode in the first discharge cycle improves. However, when the content of the electronically conductive agent is too high, the specific capacity may saturate or decrease slightly. For example, in Example 12, when the content of the electronically conductive agent was 5%, the specific capacity was relatively high, but when the content of the electronically conductive agent increased to 10% (Example 14), the increase in specific capacity was relatively small; and with the increase in the content of the electronically conductive agent, the capacity retention rate after 200 cycles actually decreased.

[0137] The test results from Examples 16-19 and 23 show that the type of additive has a relatively small impact on the specific capacity of the first discharge cycle of the positive electrode. Excessive additive content will affect the uniform dispersion of materials in the positive electrode, leading to a decrease in specific capacity. Conversely, insufficient additive content will affect the adhesion of material particles in the positive electrode, increasing the positive electrode impedance and decreasing the specific capacity.

[0138] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A positive electrode sheet characterized by comprising: The positive electrode active material layer includes a positive electrode active material, an electron conductive agent, an ion conductive agent, and an auxiliary agent, a particle size ratio of the positive electrode active material to the ion conductive agent is (1:1)-(1:0.05).

2. The positive electrode sheet according to claim 1, characterized by The particle size of the positive electrode active material is 0.2-30 μm, and the particle size of the ion conductive agent is 0.01-30 μm.

3. The positive electrode sheet according to claim 1, characterized by The ion conductive agent includes a halide solid-state electrolyte including a compound represented by Formula 1, Li a (M b )X c , Formula 1 M includes one or more of Ga, Y, In, Mg, Sr, Sc, Al, Fe, Zr, Hf, Ta, Nb, W, and lanthanide metal elements, X includes one or more of halogen elements; 0.5≤a≤6, 0.2≤b≤4, c=a+bε, wherein ε is the weighted average valence of M.

4. The positive electrode sheet according to claim 3, characterized by The halide solid state electrolyte comprises one or more of LiAlF4, Li3YCl6, Li3InCl6, Li3InCl 5.5 F 0.5 , Li3TaCl6, Li 0.388 Ta 0.238 La 0.475 Cl3.

5. The positive electrode sheet according to claim 1, characterized by The positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium iron manganese phosphate, lithium iron phosphate, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium-rich manganese-based, lithium nickel manganese oxide, and lithium vanadium oxyphosphate.

6. The positive electrode sheet according to claim 1, characterized by The electron conductive agent includes one or more of graphite, hard carbon, soft carbon, carbon nanotubes, graphene, porous carbon, superconducting carbon black, acetylene black, and furnace black.

7. The positive electrode sheet according to claim 1, characterized by The auxiliary agent includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, styrene butadiene rubber, hydrogenated nitrile rubber, boronized polyethylene glycol, cellulose, cellulose ester, cellulose ether, nitrocellulose, carboxyalkyl cellulose, cellulose salt, sodium carboxymethyl cellulose, cellulose salt derivative, polyacrylic acid, polyamide, polyvinyl alcohol, polyethyleneimine, and polyimide.

8. The positive electrode sheet according to claim 1, characterized by The mass content of the ion conductive agent is 5-50%, the mass content of the electron conductive agent is 0.05-5%, and the mass content of the auxiliary agent is 0.1-10%, based on the content of the active material layer being 100%.

9. The positive electrode sheet according to claim 1, characterized by The current collector is selected from an aluminum metal current collector or a composite current collector, and the composite current collector includes a base film and a conductive layer arranged on both sides of the base film.

10. The positive electrode sheet according to claim 9, characterized by The base film includes one or more of polyethylene, polyethylene terephthalate, polyimide, polypropylene, polyethylene, polyamide, and polyphenylene sulfide; and the conductive layer includes an aluminum layer.

11. The positive electrode sheet according to claim 10, characterized by The thickness of the positive electrode sheet is 20 μm-6 mm. The thickness of the base film is 1-300 μm, and the thickness of the conductive layer is 0.5-100 μm.

12. The positive electrode sheet according to claim 10, characterized by An adhesive layer is arranged between the active material layer and the current collector, and the adhesive layer includes a conductive adhesive and a conductive filler, the conductive adhesive includes epoxy resin, and the conductive filler includes one or more of silver, nickel, copper, aluminum, carbon black, graphite, carbon nanotubes, graphene, and silver-modified carbon nanotubes.

13. A method of producing the positive electrode sheet according to any one of claims 1 to 12, characterized by, The method includes the following steps: The positive electrode active material, ion conductive agent, electron conductive agent, auxiliary agent, and dispersant are mixed to obtain a slurry; The slurry is coated on the current collector, and a positive electrode sheet is obtained after drying.

14. The method of producing a positive electrode sheet according to claim 13, characterized by, The dispersant includes one or more of toluene, acetonitrile, 1-hexene, diethyl ether, N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dimethyl sulfoxide.

15. A method of producing the positive electrode sheet according to any one of claims 1 to 12, characterized by, The method includes the following steps: The positive electrode active material, ion conductive agent, electron conductive agent, and auxiliary agent are mixed to obtain a mixed powder; applying a shearing force to the mixed powder to fibrillate the auxiliary agent, to obtain a green material; extruding or rolling the green material into a self-supporting film, and compounding the self-supporting film with the current collector to roll to form the positive electrode sheet.

16. The method of producing a positive electrode sheet according to claim 15, characterized by, The applying a shearing force to the mixed powder comprises stirring the mixed powder, the stirring speed is 500-3000 rpm, and the stirring time is 10-60 min.

17. The method of producing a positive electrode sheet according to claim 15, characterized by, The adjuvant is selected from polytetrafluoroethylene having a molecular weight of 10 6 -10 8 g / mol.

18. The method of producing a positive electrode sheet according to claim 15, characterized by, The rolling temperature is 60-200 ℃.

19. A method of producing the positive electrode sheet according to any one of claims 1 to 12, characterized by, The method comprises the following steps: mixing the positive electrode active material, the ion conductive agent, the electron conductive agent, and the auxiliary agent to obtain a mixed powder; spraying the mixed powder onto the current collector, and hot-pressing the current collector loaded with the mixed powder to obtain a positive electrode sheet.

20. The method of producing a positive electrode sheet according to claim 19, characterized by, The spraying method for spraying the mixed powder onto the current collector is electrostatic powder spraying, and the conditions of the electrostatic powder spraying comprise: a charging voltage of 15-90 kV, a carrier gas pressure of 10-100 psi, and an auxiliary gas selected from argon, and a gap distance between a spray gun head and the current collector of 2-30 cm.

21. The method of producing a positive electrode sheet according to claim 20, characterized by, The hot-pressing is hot rolling, and the hot rolling temperature is 60-200 ℃.

22. A battery, characterized by The battery is a solid-state battery or a semi-solid-state battery, the solid-state battery or the semi-solid-state battery comprises a negative electrode, a solid-state electrolyte, and the positive electrode sheet according to any one of claims 1-12, or, the solid-state battery or the semi-solid-state battery comprises the positive electrode sheet prepared by the preparation method of the positive electrode sheet according to claim 13 or 14; or, the solid-state battery or the semi-solid-state battery comprises the positive electrode sheet prepared by the preparation method of the positive electrode sheet according to any one of claims 15-18; or, the solid-state battery or the semi-solid-state battery comprises the positive electrode sheet prepared by the preparation method of the positive electrode sheet according to any one of claims 19-21.

23. The battery of claim 22, wherein, The solid-state electrolyte comprises one or more of a halide solid-state electrolyte, a sulfide solid-state electrolyte, an oxide solid-state electrolyte, a polymer solid-state electrolyte, and a composite solid-state electrolyte; The negative electrode is selected from one of a lithium metal, a lithium alloy, a graphite negative electrode, a silicon-oxygen negative electrode, a silicon-carbon negative electrode, a silicon negative electrode, a tin negative electrode, a tin oxide negative electrode, and a tin alloy negative electrode, and the lithium alloy comprises an alloy formed by lithium and one or more of gold, indium, magnesium, zinc, chromium, nickel, molybdenum, tungsten, vanadium, titanium, niobium, zirconium, cobalt, manganese, aluminum, copper, boron, silver, tin, silicon, carbon, and phosphorus; or, the negative electrode is selected from a lithium-free negative electrode.

24. The battery of claim 23, wherein, The halide solid-state electrolyte comprises one or more of Li3YCl6, Li3ScCl6, and Li3YBr6; The sulfide solid-state electrolyte comprises one or more of LGPS, LPS, and LPSCl; The oxide solid-state electrolyte comprises one or more of LLZO, LLZTO, LLTO, LATP, and LAGP; The polymer solid-state electrolyte comprises one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate. The composite solid-state electrolyte comprises an inorganic filler and a polymer matrix, the inorganic filler comprises one or more of an oxide solid-state electrolyte, a sulfide solid-state electrolyte, a halide solid-state electrolyte; the polymer matrix comprises one or more of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate.

25. An electrical appliance, characterized in that, A battery comprising the battery of any one of claims 22-24.

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