A low-strain high-stability low-pressure positive electrode material, a preparation method thereof, a positive electrode sheet, a solid-state battery, and an electric device

Abstract

This application provides a low-strain, high-stability, low-pressure cathode material and its preparation method, cathode electrode, solid-state battery, and electrical device, relating to the field of solid-state batteries. The low-strain, high-stability, low-pressure cathode material includes a core-shell cathode material and a first coating layer and a second coating layer sequentially disposed on the surface of the core-shell cathode material. The core-shell cathode material includes a first core and a first outer shell disposed on the surface of the first core. The molar concentration of nickel in the first core is higher than that in the first outer shell, and the molar concentration of manganese in the first core is lower than that in the first outer shell. The first outer shell also includes a dopant element M. The first coating layer includes a metal compound and a fluoride. The second coating layer includes a boride. This low-strain, high-stability, low-pressure cathode material maintains high capacity utilization, reduces external stress release, and releases stress into the material interior under low pressure, avoiding interface damage and improving the material's capacity utilization under low pressure.

Description

Technical Field

[0001] This application relates to the field of solid-state batteries, and in particular to a low-strain, high-stability, low-pressure cathode material and its preparation method, cathode sheet, solid-state battery, and electrical device. Background Technology

[0002] Solid-state batteries are considered a crucial development direction for next-generation electrochemical energy storage systems due to their high safety and high energy density potential. The performance of the cathode material has a critical impact on the overall battery performance. However, current cathode materials for solid-state batteries still have significant shortcomings in practical applications. On the one hand, poor solid-solid interface contact between the solid electrolyte and the cathode active material leads to impaired ion transport and increased interfacial impedance. On the other hand, under low-pressure operating conditions, the structural stability of the cathode material is insufficient, making it prone to strain accumulation and performance degradation, severely affecting the battery's cycle life and rate performance. These problems further limit the practical application of solid-state batteries.

[0003] Therefore, it is urgent to optimize the structure or composition of cathode materials to improve the solid-solid interface contact state, reduce the strain of the material during charging and discharging, and ensure that it can maintain stable electrochemical output under low pressure conditions. Summary of the Invention

[0004] The purpose of this application is to provide a low-strain, high-stability, low-pressure cathode material and its preparation method, cathode sheet, solid-state battery, and electrical device to solve the above-mentioned problems.

[0005] To achieve the above objectives, the first aspect of this application provides a low-strain, high-stability, low-pressure cathode material, comprising a core-shell cathode material and a first coating layer and a second coating layer sequentially disposed on the surface of the core-shell cathode material; The core-shell cathode material includes a first core and a first shell disposed on the surface of the first core. The nickel molar concentration in the first core is higher than that in the first shell, and the manganese molar concentration in the first core is lower than that in the first shell. The first shell also includes a doping element M, which includes at least four of Zr, Cr, Al, W, Ta, Mg, Ca, Ti, Mo, Nb, and B. The first coating layer comprises a metal compound and a fluoride; The second coating layer includes a boride.

[0006] Optionally, the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The general structural formula of the core-shell cathode material is: Li a Ni x Co y Mn z Mw O2, where 1.02≤a≤1.2, 0.6≤x≤1, 0≤y≤0.2, 0≤z≤0.2, 0 <w≤0.4,x+y+z+w=1; (2) The mass fraction of nickel in the first core in the core-shell cathode material is 24-58%; (3) The mass fraction of nickel in the first outer shell in the core-shell cathode material is 0.3-22%; (4) The cell volume expansion of the low-strain, high-stability, low-pressure cathode material is 0.05%-0.8%; (5) The core-shell cathode material further includes a cavity, which accounts for 0.2-13% of the total volume of the core-shell cathode material.

[0007] Optionally, the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The diameter of the first core is 1.1-3.18 μm; (2) The thickness of the first outer shell is 0.01-0.25 μm; (3) The thickness of the first coating layer is 30-170 μm; (4) The thickness of the second coating layer is 1-65 μm; (5) The particle size of the low strain, high stability and low pressure cathode material is 100-500 mesh.

[0008] A second aspect of this application provides a method for preparing the aforementioned low-strain, high-stability, low-pressure cathode material, comprising: A core-shell precursor is provided, the core-shell precursor comprising a first core and a first shell disposed on the surface of the first core, wherein the nickel content in the second core is higher than that in the second shell, and the manganese content in the second core is lower than that in the second shell; Under an oxygen-containing atmosphere, the core-shell precursor and the M-containing additive are first mixed and first sintered to obtain a first sintered product; Under an oxygen-containing atmosphere, the first sintered product and the first lithium salt are mixed and sintered a second time to obtain the second sintered product. Under an oxygen-containing atmosphere, the second sintered product and the second lithium salt are mixed and sintered in a third manner to obtain the third sintered product. Under an oxygen-containing atmosphere, the third sintering product, the transition metal compound, and the fluorine-containing compound are mixed and sintered in a fourth manner to obtain a fourth sintering product. The fourth sintering product and the boride are mixed and sintered in a fifth process to obtain a low-strain, high-stability, low-pressure cathode material.

[0009] Optionally, the preparation method of the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The M-containing additive includes at least one of the following: oxides, hydroxides, carbonate compounds, halides, sulfides, and phosphate compounds containing M; (2) The first lithium salt and the second lithium salt each independently include at least one of lithium carbonate, lithium hydroxide, lithium oxide, lithium sulfide and lithium methyl; (3) The transition metal compound includes at least one of ammonium tungstate, tungsten trioxide, manganese carbonate, manganese oxide, manganese tetroxide, lithium tungstate, molybdenum trioxide, ammonium molybdate, titanium dioxide, cobalt tetroxide, cobalt hydroxyl oxide, cobalt oxide, aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, niobium pentoxide, niobic acid, lanthanum oxide, antimony oxide, cerium oxide, tellurium oxide, niobic acid, lithium niobate, and yttrium oxide; (4) The fluorine-containing compound includes at least one of lithium fluoride, aluminum fluoride, ammonium fluoride, ammonium hydrogen fluoride, magnesium fluoride and calcium fluoride; (5) The borides include at least one of boric acid, zirconium boride, lithium borate, boron oxide, lithium thioborate, boron nitride, lithium tetraborate, lithium metaborate, lithium triborate and titanium boride; (6) The D50 of the core-shell precursor is 1.4-3.4 μm, the diameter of the second core is 0.9-3.38 μm, the thickness of the second shell is 0.01-0.25 μm, the mass fraction of nickel in the second core in the core-shell cathode material is 24-58%, and the mass fraction of nickel in the second shell in the core-shell cathode material is 0.3-22%.

[0010] Optionally, the preparation method of the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The additive containing M accounts for 500-3000 ppm of the total material in the first mixture; (2) The molar ratio of the first sintered product to the first lithium salt is 1:a', and 0.612≤a'<1.2; (3) The molar ratio of the transition metal to the second lithium salt in the second sintered product is 1:a'', 0 <a''≤0.588; (4) The transition metal compound accounts for 500-15000 ppm of the total material of the fourth mixture, and the fluorine-containing compound accounts for 500-10000 ppm of the total material of the fourth mixture; (5) The boride accounts for 500-2000 ppm of the total material of the fifth mixture.

[0011] Optionally, the preparation method of the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The heating rate of the first sintering is 1-8℃ / min, the final temperature is 450-800℃, the holding time is 6-12h, and the cooling rate is 1-8℃ / min; (2) The second sintering includes sequential low-temperature sintering and high-temperature sintering; the heating rate of the low-temperature sintering is 1-10℃ / min, the final temperature is 250-550℃, and the holding time is 1-16h; the heating rate of the high-temperature sintering is 1-8℃ / min, the final temperature is 500-800℃, the holding time is 4-24h, the cooling rate is 1-8℃ / min, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; (3) The heating rate of the third sintering is 5-15℃ / min, the final temperature is 700-900℃, the isothermal time is 1-12h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; (4) The heating rate of the fourth sintering is 2-6℃ / min, the final temperature is 500-750℃, the isothermal time is 4-16h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 95%-100%; (5) The heating rate of the fifth sintering is 2-8℃ / min, the final temperature is 200-350℃, and the holding time is 1-16h.

[0012] A third aspect of this application provides a positive electrode sheet, comprising the aforementioned low-strain, high-stability, low-pressure positive electrode material.

[0013] A fourth aspect of this application provides a solid-state battery, including the aforementioned positive electrode.

[0014] The fifth aspect of this application provides an electrical device including the aforementioned solid-state battery.

[0015] Compared with the prior art, the beneficial effects of this application include: The low-strain, high-stability, low-pressure cathode material provided in this application has a first shell doped with high-entropy elements, which can reduce the overall lattice strain of the low-strain, high-stability, low-pressure cathode material and reduce its volume expansion during cycling. The first coating layer is co-coated with metal compounds and fluorides. Me-O bonds stabilize surface oxygen, and fluorides provide fluorination anchoring, synergistically inhibiting oxygen loss. Fluorine can partially replace oxygen in the lattice, forming stronger "transition metal-fluorine (TM-F)" chemical bonds. This stronger bond energy effectively "anchors" transition metal ions, significantly improving the stability of the lattice framework. Fluorine can also migrate to oxygen vacancies near the material surface and fill them. This repair process effectively prevents oxygen defects from diffusing from the material surface to the interior, cutting off the chain reaction of oxygen evolution. The high ionic conductivity provided by the metal compounds and the increased interfacial impedance that may be caused by fluorides complement each other. The second coating layer, boride, improves the contact with sulfide solid electrolyte, enhancing the capacity and cycling performance of the material under low stress in all-solid state. In summary, the high-nickel, low-manganese core and the low-nickel, high-manganese, and high-entropy doping of the first shell enable the low-strain, high-stability, low-pressure cathode material to maintain a high capacity, reduce external stress release, and release stress into the material interior under low pressure, avoiding damage to the interface and improving the material's capacity under low pressure.

[0016] The method for preparing low-strain, high-stability, low-pressure cathode material provided in this application first involves doping with a high-entropy element M. The M element can stably occupy the transition metal sites, acting like a "nail" to significantly inhibit the migration ability of surrounding nickel, cobalt, and other ions, thus enabling the material to form an effective core-shell structure (gradient distribution of nickel and manganese) during the subsequent sintering process. In addition, a stepwise lithium addition and multi-stage sintering process are adopted to ensure that the low-strain, high-stability, low-pressure cathode material maintains its core-shell structure. The positive electrode, solid-state battery, and electrical equipment provided in this application have good thermal safety stability and high capacity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0018] Figure 1 SEM image of the low-strain, high-stability, low-pressure cathode material provided in Example 1; Figure 2 Elemental analysis diagram from center to edge of the cross-section of the low-strain, high-stability, low-pressure cathode material provided in Example 2. Detailed Implementation

[0019] First, the solution provided in this application will be explained in more detail as follows: The first aspect of this application provides a low-strain, high-stability, low-pressure cathode material, comprising a core-shell cathode material and a first coating layer and a second coating layer sequentially disposed on the surface of the core-shell cathode material; The core-shell cathode material includes a first core and a first shell disposed on the surface of the first core. The nickel molar concentration in the first core is higher than that in the first shell, and the manganese molar concentration in the first core is lower than that in the first shell. The first shell also includes a doping element M, which includes at least four of Zr, Cr, Al, W, Ta, Mg, Ca, Ti, Mo, Nb, and B. Preferably, M includes at least four of Zr, Al, W, Mg, Ti, Nb, and Mo; The first coating layer comprises a metal compound and a fluoride; The second coating layer includes a boride.

[0020] It is important to note that the boride coating, metal compound, and fluoride co-coating layers work synergistically, with the inner layer forming a solid oxygen and high ionic conductivity design, and the outer boron coating layer forming a uniform coating on the surface, improving the contact between the material and the solid electrolyte, and enhancing the material's initial efficiency and capacity utilization.

[0021] In some embodiments, the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The general structural formula of the core-shell cathode material is: Li a Ni x Co y Mn z M w O2, where 1.02≤a≤1.2, 0.6≤x≤1, 0≤y≤0.2, 0≤z≤0.2, 0 <w≤0.4,x+y+z+w=1; Optionally, in the general structural formula of the core-shell cathode material, a can be any value between 1.02, 1.05, 1.1, 1.15, 1.2 or 1.02-1.2, x can be any value between 0.6, 0.7, 0.8, 0.9, 1 or 0.6-1, y can be any value between 0, 0.1, 0.2 or 0-0.2, and z can be any value between 0.001, 0.01, 0.1, 0.2, 0.3, 0.4 or greater than 0 and less than or equal to 0.4; Preferably, 1.05≤a≤1.15, 0.8≤x≤0.98; (2) The mass fraction of nickel in the first core in the core-shell cathode material is 24-58%; Optionally, the mass fraction of nickel in the first core in the core-shell cathode material can be any value between 24%, 30%, 40%, 50%, 58%, or 24-58%. (3) The mass fraction of nickel in the first outer shell in the core-shell cathode material is 0.3-22%; Optionally, the mass fraction of nickel in the first outer shell in the core-shell cathode material can be any value between 0.3%, 1%, 5%, 10%, 15%, 20%, 22%, or 0.3-22%. (4) The cell volume expansion of the low-strain, high-stability, low-pressure cathode material is 0.05%-0.8%; Optionally, the cell volume expansion of the low-strain, high-stability, low-pressure cathode material can be any value between 0.05%, 0.06%, 0.07%, 0.08%, or 0.05-0.08%. (5) The core-shell cathode material further includes a cavity, which accounts for 0.2%-13% of the total volume of the core-shell cathode material.

[0022] Optionally, the cavity can occupy any value between 0.2%, 1%, 5%, 10%, 13% or 0.2-13% of the total volume of the core-shell cathode material.

[0023] It is important to note that the high entropy of the outer layer of the core-shell cathode material provided in this application can reduce the overall lattice strain of the material, reduce the volume expansion of the material during cycling, and, combined with the second coating layer of boride, improve the contact with the sulfide solid electrolyte, enhancing the capacity and cycling performance of the material under low stress in all-solid state. The low Ni, high entropy design of the outer layer, combined with fluoride coating, further stabilizes the oxygen in the material, prevents oxygen evolution, and improves the thermal safety and stability of the material. The co-coating of metal compounds and fluorides stabilizes surface oxygen through Me-O bonds, while fluorides provide fluorination anchoring, synergistically inhibiting oxygen loss. Fluorine can partially replace oxygen in the lattice, forming a stronger "transition metal-fluorine (TM-F)" chemical bond. This stronger bond effectively "anchors" transition metal ions, significantly improving the stability of the lattice framework. Fluorine can also migrate to oxygen vacancies near the material surface and fill them. This repair process is equivalent to "plugging" the weak links in the lattice, effectively preventing oxygen defects from diffusing from the material surface to the interior, and cutting off the chain reaction of oxygen evolution. The high ionic conductivity of the metal compound complements the increased interfacial impedance that may be caused by fluoride; the boride coating layer and the metal compound / fluoride co-coating layer work synergistically, with the inner layer forming a solid oxygen and high ionic conductivity design, and the outer boron coating layer forming a uniform coating on the surface, improving the contact between the material and the solid electrolyte, and enhancing the material's first efficiency and capacity utilization.

[0024] In some embodiments, the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The diameter of the first core is 1.1-3.18 μm; Optionally, the diameter of the first core can be 1.1 μm, 2 μm, 3 μm, 3.18 μm, or any value between 1.1 and 3.18 μm; (2) The thickness of the first outer shell is 0.01-0.25 μm; Optionally, the thickness of the first shell can be any value between 0.01 μm, 0.05 μm, 0.1 μm, 0.2 μm, 0.25 μm, or 0.01-0.25 μm; (3) The thickness of the first coating layer is 30-170 μm; Optionally, the thickness of the first coating layer can be any value between 30 μm, 60 μm, 90 μm, 120 μm, 150 μm, 170 μm or 30-170 μm; (4) The thickness of the second coating layer is 1-65 μm; Optionally, the thickness of the second coating layer can be any value between 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 65 μm or 1-65 μm; (5) The particle size of the low strain, high stability and low pressure cathode material is 100-500 mesh.

[0025] Optionally, the particle size of the low-strain, high-stability, low-pressure cathode material can be any value between 100 mesh, 200 mesh, 300 mesh, 400 mesh, 500 mesh, or 100-500 mesh.

[0026] A second aspect of this application provides a method for preparing the aforementioned low-strain, high-stability, low-pressure cathode material, comprising: A core-shell precursor is provided, the core-shell precursor comprising a second core and a second shell disposed on the surface of the second core, wherein the nickel content in the second core is higher than that in the second shell, and the manganese content in the second core is lower than that in the second shell; Under an oxygen-containing atmosphere, the core-shell precursor and the M-containing additive are first mixed and first sintered to obtain a first sintered product; In some embodiments, the rotation speed of the first mixing is 300-1000 rpm, preferably 600-800 rpm; the mixing time is 20-45 min. Under an oxygen-containing atmosphere, the first sintered product and the first lithium salt are mixed and sintered a second time to obtain the second sintered product. In some embodiments, the second mixing speed is 500-1100 rpm, preferably 700-900 rpm, and the mixing time is 20-40 min; Under an oxygen-containing atmosphere, the second sintered product and the second lithium salt are mixed and sintered in a third manner to obtain the third sintered product. In some embodiments, the rotation speed of the third mixing is 500-1100 rpm, preferably 700-900 rpm, and the mixing time is 20-40 min; Under an oxygen-containing atmosphere, the third sintering product, the transition metal compound, and the fluorine-containing compound are mixed and sintered in a fourth manner to obtain a fourth sintering product. The fourth sintering product and the boride are mixed and sintered in a fifth process to obtain a low-strain, high-stability, low-pressure cathode material.

[0027] It should be noted that the first mixing, second mixing, third mixing, fourth mixing, and fifth mixing in the preparation method of this application each independently include one or more of the following: grinding mixing, high-speed mixer mixing, food processor mixing, and dry grinding mixing; in addition, the gas in the oxygen-containing atmosphere includes air and / or oxygen.

[0028] In some embodiments, the method for preparing the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The M-containing additive includes at least one of the following: oxides, hydroxides, carbonate compounds, halides, sulfides, and phosphate compounds containing M; (2) The first lithium salt and the second lithium salt each independently include at least one of lithium carbonate, lithium hydroxide, lithium oxide, lithium sulfide and lithium methyl; (3) The transition metal compound includes at least one of ammonium tungstate, tungsten trioxide, manganese carbonate, manganese oxide, manganese tetroxide, lithium tungstate, molybdenum trioxide, ammonium molybdate, titanium dioxide, cobalt tetroxide, cobalt hydroxyl oxide, cobalt oxide, aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, niobium pentoxide, niobic acid, lanthanum oxide, antimony oxide, cerium oxide, tellurium oxide, niobic acid, lithium niobate, and yttrium oxide; (4) The fluorine-containing compound includes at least one of lithium fluoride, aluminum fluoride, ammonium fluoride, ammonium hydrogen fluoride, magnesium fluoride and calcium fluoride; (5) The borides include at least one of boric acid, zirconium boride, lithium borate, boron oxide, lithium thioborate, boron nitride, lithium tetraborate, lithium metaborate, lithium triborate and titanium boride; The D50 of the core-shell precursor is 1.4 - 3.4 μm, and the diameter of the second core is 0.9 - 3.38 μm; the thickness of the second shell is 0.01 - 0.25 μm, and the mass fraction of nickel in the second core in the core-shell cathode material is 24 - 58%; the mass fraction of nickel in the second shell in the core-shell cathode material is 0.3 - 22%.

[0029] Optionally, the D50 of the core-shell precursor can be 1.4 μm, 1.6 μm, 2 μm, 3 μm, 3.2 μm, 3.4 μm, or any value between 1.4 - 3.4 μm; the diameter of the second core can be 0.9 μm, 1.1 μm, 1.58 μm, 2 μm, 2.5 μm, 3 μm, 3.18 μm, 3.38 μm, or any value between 0.9 - 3.38 μm; the thickness of the second shell can be 0.01 μm, 0.1 μm, 0.2 μm, 0.25 μm, or any value between 0.01 - 0.25 μm; the mass fraction of nickel in the second core in the core-shell cathode material can be 24%, 30%, 40%, 50%, 58%, or any value between 24 - 58%; the mass fraction of nickel in the second shell in the core-shell cathode material can be 0.3%, 1%, 5%, 10%, 20%, 22%, or any value between 0.3 - 22%.

[0030] In some embodiments, the method for preparing the low-strain, high-stability, and low-pressure cathode material satisfies at least one of the following conditions: (1) The M-containing additive accounts for 500 - 3000 ppm of the total materials in the first mixing; Optionally, the M-containing additive can account for 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm, or any value between 500 - 3000 ppm of the total materials in the first mixing; (2) The molar ratio of the transition metal to the first lithium salt in the first sintered product is 1:a', where 0.612 ≤ a' < 1.2; Optionally, the molar ratio of the transition metal to the first lithium salt in the first sintered product can be 1:0.612, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, or 1:a', and the range value of 0.612 ≤ a' < 1.2; (3) The molar ratio of the transition metal to the second lithium salt in the second sintered product is 1:a'', where 0 < a'' ≤ 0.588; Optionally, the molar ratio of the transition metal to the second lithium salt in the second sintered product can be 1:0.01, 1:0.1, 1:0.3, 1:0.4, 1:0.5, 1:0.588, or 1:a'', and the range value of 0 < a'' ≤ 0.588; It should be noted that a = a' + a''; (4) The transition metal compound accounts for 500-15000 ppm of the total material of the fourth mixture, and the fluorine-containing compound accounts for 500-10000 ppm of the total material of the fourth mixture; Optionally, the transition metal compound may account for any value between 500 ppm, 1000 ppm, 5000 ppm, 10000 ppm, 15000 ppm or 500-15000 ppm of the total material of the fourth mixture, and the fluorine-containing compound may account for any value between 500 ppm, 1000 ppm, 5000 ppm, 10000 ppm or 500-10000 ppm of the total material of the fourth mixture; It should be noted that when the content of transition metal compounds is too low, the compounds cannot form a continuous conductive network, the coating effect on the material surface is weakened, and the ionic conductivity cannot be effectively improved, nor can the residual lithium be effectively reduced. When the content of transition metal compounds is too high, the coating on the material surface is too large, which may cause particle agglomeration and affect ion transport and capacity utilization. When the content of fluorine-containing compounds is too low, the fluorine-containing compounds cannot effectively anchor lattice oxygen and inhibit oxygen evolution; when the content of fluorine-containing compounds is too high, the material surface is coated with too much, which increases the interfacial impedance of the material surface and affects the rate performance of the material. Preferably, the transition metal compound accounts for 500-15000 ppm of the total material of the fourth mixture, more preferably 2000-10000 ppm, and the fluorine-containing compound accounts for 500-10000 ppm of the total material of the fourth mixture, more preferably 1500-3000 ppm. (5) The boride accounts for 500-2000 ppm of the total material of the fifth mixture.

[0031] Optionally, the boride may account for any value between 500 ppm, 1000 ppm, 1500 ppm, 2000 ppm or 500-2000 ppm of the total material in the fifth mixture.

[0032] It is important to note that when the boride content is too low, it may lead to incomplete neutralization of residual lithium on the surface and the inability of boron-containing substances to form a uniform coating on the material surface, resulting in degradation of the material surface structure. When the boride content is too high, it may invade the crystal lattice, destroy the near-surface crystal structure, and hinder lithium-ion diffusion.

[0033] In some embodiments, the method for preparing the low-strain, high-stability, low-pressure cathode material satisfies at least one of the following conditions: (1) The heating rate of the first sintering is 1-8℃ / min, the final temperature is 450-800℃, the holding time is 6-12h, and the cooling rate is 1-8℃ / min; Optionally, the heating rate of the first sintering can be any value between 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min or 1-8℃ / min; the final temperature can be any value between 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃ or 450-800℃; the isothermal time can be any value between 6h, 7h, 8h, 9h, 10h, 11h, 12h or 6-12h; and the cooling rate can be any value between 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min or 1-8℃ / min. It should be noted that if the first sintering temperature is too low, multiple elements may not be able to be well doped into the precursor. If the sintering temperature is too high, doping may enter the core and fail to form high-entropy doping on the surface, thus failing to form effective barriers in the subsequent stages. Preferably, the heating rate of the first sintering is 3-6℃ / min, the final temperature is 500℃-700℃, and the holding time is 8-10h. (2) The second sintering includes sequential low-temperature sintering and high-temperature sintering; the heating rate of the low-temperature sintering is 1-10℃ / min, the final temperature is 250-550℃, and the holding time is 1-16h; the heating rate of the high-temperature sintering is 1-8℃ / min, the final temperature is 500-800℃, the holding time is 4-24h, the cooling rate is 1-8℃ / min, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; Optionally, the heating rate for low-temperature sintering can be any value between 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min, or 1-10℃ / min; the endpoint temperature can be any value between 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, or 250-550℃; and the isothermal time can be any value between 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, or 1-16 h. The heating rate for high-temperature sintering can be any value between h; the heating rate can be 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, 10℃ / min or any value between 1-10℃ / min; the final temperature can be any value between 500℃, 600℃, 700℃, 800℃ or 500-800℃; the isothermal time can be any value between 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, 16 h, 20 h, 24 h or 4-24 h; the cooling rate can be any value between 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min or 1-8℃ / min; and the gas flow rate can be 8 m / min. 3 / h, 10 m 3 / h, 20m 3 / h、30 m 3 / h or 8-30 m 3 Any value between / h, the oxygen content can be 90%, 95%, 100% or any value between 90 and 100%; It is important to note that if the low-temperature sintering temperature is too low, the sintering temperature may be insufficient, resulting in incomplete melting of the lithium salt and its inability to fully penetrate into the precursor. If the low-temperature sintering temperature is too high, the lithium salt may form a layered structure on the surface of the precursor. If the high-temperature sintering temperature is too low, the sintering temperature may be insufficient, resulting in incomplete material crystallization and low material capacity. If the high-temperature sintering temperature is too high, over-sintering may occur, leading to severe agglomeration of material particles. It is also possible that the lithium salt and the core-shell portion of the precursor preferentially form a ternary layered structure, preventing the formation of a significant layered structure inside the material. Preferably, the heating rate for low-temperature sintering is 3-6℃ / min, the final temperature is 470-520℃, and the holding time is 4-10h; the heating rate for high-temperature sintering is 3-6℃ / min, the final temperature is 600-700℃, and the holding time is 8-14h. (3) The heating rate of the third sintering is 5-15℃ / min, the final temperature is 700-900℃, the isothermal time is 1-12h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; Optionally, the heating rate of the third sintering can be any value between 5℃ / min, 10℃ / min, 15℃ / min, or 5-15℃ / min; the final temperature can be any value between 700℃, 800℃, 900℃, or 700-900℃; the isothermal time can be any value between 1h, 4h, 8h, 12h, or 1-12h; and the gas flow rate can be 8m³ / min. 3 / h, 10 m 3 / h、20 m 3 / h、30 m 3 / h or 8-30 m 3 Any value between / h, the oxygen content can be 90%, 95%, 100% or any value between 90 and 100%; It is important to note that if the third sintering temperature is too low, insufficient sintering temperature may occur, resulting in incomplete material crystallization and low material capacity. If the sintering temperature is too high, over-sintering may occur, leading to severe agglomeration of material particles. It may also cause lithium salt and core-shell precursors to preferentially form a ternary layered structure, preventing the formation of a significant layered structure within the material. The high-temperature treatment time should be controlled between 1 and 12 hours. If the high-temperature treatment time is too long, it may cause diffusion of transition metal elements in the core-shell precursors. If the high-temperature treatment time is too short, it may prevent the outer shell from forming good crystallization. The high-temperature heating rate should be controlled between 5 and 15°C / min. If the heating rate is too slow, it may cause diffusion of transition metal elements in the core-shell precursors. If the heating rate is too fast, it may cause the sintering equipment to be unable to withstand the pressure. Preferably, the final temperature of the third sintering is 700-800℃, and the holding time is 2-6h; (4) The heating rate of the fourth sintering is 2-6℃ / min, the final temperature is 500-750℃, the isothermal time is 4-16h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 95%-100%; Optionally, the heating rate of the fourth sintering can be any value between 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, or 2-6℃ / min; the final temperature can be any value between 500℃, 600℃, 700℃, 750℃, or 500-750℃; the isothermal time can be any value between 4 h, 8 h, 12 h, 16 h, or 1-16 h; and the gas flow rate can be 8 m³ / min. 3 / h, 10 m 3 / h、20 m 3 / h、30 m 3 / h or 8-30 m 3 Any value between / h, the oxygen content can be 90%, 95%, 100% or any value between 90 and 100%; It is important to note that if the fourth sintering temperature is too low, the coating agent may not be able to adhere strongly to the material surface, leading to rapid capacity decay in subsequent cycles. If the fourth sintering temperature is too high, the coating agent elements may sinter into the material, affecting the material's solid-state capacity. If the fourth sintering time is too short, the coating agent elements may not complete the decomposition and chemical reaction on the material surface and cannot adhere effectively. If the fourth sintering time is too long, the coating agent elements may be doped into the material surface. Preferably, the heating rate of the fourth sintering is 3-5℃ / min, the final temperature is 600-680℃, and the holding time is 6-12h. (5) The heating rate of the fifth sintering is 2-8℃ / min, the final temperature is 200-350℃, and the holding time is 1-16h.

[0034] Optionally, the heating rate of the fifth sintering can be any value between 2℃ / min, 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min or 2-8℃ / min, the endpoint temperature can be any value between 200℃, 250℃, 300℃, 350℃ or 200-350℃, and the isothermal time can be any value between 4 h, 8 h, 12 h, 16 h or 1-16 h.

[0035] It should be noted that if the fifth sintering temperature is too low, the coating layer may not be fully transformed, resulting in uneven coating and poor crystallinity, leading to poor ionic conductivity. If the fifth sintering temperature is too high, boron may diffuse into the bulk lattice of the cathode material, damaging the surface lattice structure.

[0036] Preferably, the heating rate of the fifth sintering is 3-6℃ / min, the final temperature is 260-300℃, and the isothermal time is 6-10h.

[0037] A third aspect of this application provides a positive electrode sheet, comprising the aforementioned low-strain, high-stability, low-pressure positive electrode material.

[0038] A fourth aspect of this application provides a solid-state battery, including the aforementioned positive electrode.

[0039] The fifth aspect of this application provides an electrical device including the aforementioned solid-state battery.

[0040] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0041] Example 1 The first aspect of this embodiment provides a low-strain, high-stability, low-pressure cathode material, including a core-shell cathode material and a first coating layer and a second coating layer sequentially disposed on the surface of the core-shell cathode material; The core-shell cathode material comprises a core and a shell (0.06 μm thick) disposed on the surface of the core (2.4 μm in diameter). The general structural formula of the core-shell cathode material is Li. 1.03 Ni 0.88 Co 0.05 Mn 0.04 Zr 0.0021 Al 0.011 Ti 0.005 Mg 0.0119 O2, w = 0.0021 + 0.011 + 0.005 + 0.0119 = 0.03. Where x + y + z + w = ​​1, the outer shell also includes dopant elements M, which include Zr, Al, Mg, and Ti; the nickel in the core accounts for 48.93% of the mass fraction of the core-shell cathode material, and the nickel in the outer shell accounts for 5.91% of the mass fraction of the core-shell cathode material; the core-shell cathode material also includes cavities, which account for 0.46% of the total volume of the core-shell cathode material.

[0042] The first coating layer consists of a metal compound and a fluoride (95 nm thick). The second coating layer includes a boride (32 nm thick); The cell volume expansion of the low-strain, high-stability, low-pressure cathode material is 0.55%, and the particle size is 325 mesh.

[0043] The second aspect of this embodiment provides a method for preparing a low-strain, high-stability, low-pressure cathode material, the specific preparation steps of which are as follows: S1: Core-shell precursor (Ni) was prepared by co-precipitation method.0.91 Co 0.05 Mn 0.04 (OH)2), with a high-nickel ternary Ni core. 0.95 Co 0.04 Mn 0.01 (OH)2 precursor, with a medium-nickel ternary Ni shell. 0.69 Co 0.09 Mn 0.22 The (OH)₂ precursor has a D50 of 2.4 μm and a first core diameter of 2.28 μm; the second shell has a thickness of 0.06 μm; the nickel molar concentration in the second core is 95% of the total transition metals; and the nickel molar concentration in the second shell is 69% of the total transition metals. S2: Under an oxygen-containing atmosphere, the core-shell precursor and additives containing M (ZrO2 at 2000 ppm, MgO at 2700 ppm, Al2O3 at 2800 ppm, and TiO2 at 2500 ppm) are mixed at a speed of 750 rpm for 30 min, followed by a first sintering. The heating rate for the first sintering is 3℃ / min, the final temperature is 600℃, the holding time is 8 h, the cooling rate is 2℃ / min, and the gas (oxygen) flow rate is controlled at 18 m / s. 3 / h, with an oxygen content of 99%, the first sintering product is obtained; S3: Under an oxygen-containing atmosphere, the first sintering product and the first lithium salt (lithium hydroxide) are mixed. The molar ratio of the transition metal in the first sintering product to the first lithium salt is 1:0.8. The mixing speed is controlled at 800 rpm, and the mixing time is 35 min. Then, a second sintering is performed, which includes sequential low-temperature sintering and high-temperature sintering. The heating rate of the low-temperature sintering is 3℃ / min, the final temperature is 500℃, and the holding time is 9 h. The heating rate of the high-temperature sintering is 5℃ / min, the final temperature is 680℃, the holding time is 11 h, the cooling rate is 2℃ / min, and the gas (oxygen) flow rate is controlled at 18 m / s. 3 / h, with an oxygen content of 99%, the second sintering product is obtained; S4: Under an oxygen-containing atmosphere, the second sintering product and the second lithium salt (lithium hydroxide) are mixed. The molar ratio of the transition metal in the second sintering product to the second lithium salt is 1:0.22. The mixing speed is controlled at 750 rpm, and the mixing time is 30 min. Then, a third sintering is performed. The heating rate of the third sintering is 10℃ / min, the final temperature is 780℃, and the holding time is 4 h. The flow rate of the gas (oxygen) is controlled at 18 m / s. 3 / h, with an oxygen content of 99%, the third sintering product was obtained; S5: Under an oxygen-containing atmosphere, the third sintering product, transition metal compound (Co3O4), and fluorine-containing compound (lithium fluoride) are mixed. The transition metal compound accounts for 9000 ppm of the total material in the fourth mixture, and the fluorine-containing compound accounts for 2000 ppm of the total material in the fourth mixture. The mixing speed is controlled at 750 rpm, and the mixing time is 25 min. Then, the fourth sintering is carried out with a heating rate of 3℃ / min, a final temperature of 675℃, and a holding time of 8 h. The gas flow rate is controlled at 15 m / s. 3 / h, with an oxygen content of 99%, the fourth sintering product was obtained; S6: The fourth sintering product and lithium borate are mixed, with the boride accounting for 1200 ppm of the total material in the fifth mixture. Then, the fifth sintering is carried out with a heating rate of 3℃ / min, an end temperature of 300℃, a holding time of 8h, and a cooling rate of 2℃ / min to obtain a low-strain, high-stability, low-pressure cathode material.

[0044] SEM images of this low-strain, high-stability, low-pressure cathode material are shown below. Figure 1 As shown, the elemental analysis of the cross-section of the low-strain, high-stability, low-pressure cathode material from the center to the edge is as follows: Figure 2 As shown.

[0045] Example 2 The difference from Example 1 is that in step S2, the additive containing M is Cr2O3 1800ppm, WO3 2000ppm, MoO3 2500ppm, and Nb2O5 1500ppm.

[0046] Example 3 The difference from Example 1 is that in step S5, the transition metal compound is niobic acid and the fluorine-containing compound is aluminum fluoride. In step S6, the boride is boric acid.

[0047] Comparative Example 1 The difference from Example 1 is that step S2 is not performed, that is, doping of element M is not performed.

[0048] Comparative Example 2 The difference from Example 1 is that step S4 is omitted, and the amount of lithium salt used in step S3 is modified to be the sum of the first and second lithium salts in Example 1, that is, only one-step sintering of lithium salt is performed.

[0049] Comparative Example 3 The difference from Example 1 is that in step S3, only high-temperature sintering is performed, and low-temperature sintering is not performed.

[0050] Comparative Example 4 The difference from Example 1 is that step S2 is replaced after step S4 and before step S5, that is, lithium salt is added first for calcination, and then doping is performed.

[0051] Comparative Example 5 The difference from Example 1 is that steps S2-S4 are performed in one step, that is, the core-shell precursor, the M-containing additive, the first lithium salt and the second lithium salt are mixed and processed according to the sintering conditions of step S2.

[0052] Comparative Example 6 The difference from Example 1 is that step S5 is not performed, that is, the first covering layer is not set.

[0053] Comparative Example 7 The difference from Example 1 is that step S6 is not performed, that is, the second covering layer is not provided.

[0054] The relevant parameters of the low-strain, high-stability, low-pressure cathode materials provided in the above embodiments and comparative examples are shown in Table 1.

[0055] Table 1 Relevant Parameters

[0056] The cathode materials prepared in the above examples and comparative examples were assembled with lithium indium alloy to form solid-state batteries, and electrochemical performance tests were conducted (0.1C charging capacity and discharging capacity at 1.9-3.7V). The specific results are shown in Table 2.

[0057] Table 2 Electrochemical Performance Tests

[0058] analyze: As can be seen from the results in Tables 1 and 2, comparing Examples 1-2 and Comparative Examples 1-5, the removal of high-entropy elements, one-step sintering of lithium salts, changes in the order of introduction of high-entropy elements, and one-step mixed sintering will lead to the disappearance of the core-shell structure of the material, the shrinkage or even disappearance of the internal cavity, and further reduce the capacity, first efficiency and cycle performance of the material at 5 MPa.

[0059] A comparison of Example 1 and Comparative Example 6 shows that the co-coating of metal compound and fluoride effectively "anchors" the transition metal ions with stronger bond energy, significantly improving the stability of the crystal lattice framework. The high ionic conductivity provided by the metal compound and the increased interfacial impedance that may be caused by the fluoride complement each other, improving the capacity, first-efficiency performance, and cycling performance of the material at 5 MPa.

[0060] As can be seen from the comparison between Example 1 and Comparative Example 7, the borides form a uniform coating on the surface, which improves the contact between the material and the solid electrolyte and enhances the material's first efficiency and capacity utilization.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0062] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A low-strain, high-stability, low-pressure cathode material, characterized in that, It includes a core-shell cathode material and a first coating layer and a second coating layer sequentially disposed on the surface of the core-shell cathode material; The core-shell cathode material includes a first core and a first shell disposed on the surface of the first core. The molar concentration of nickel in the first core is higher than that in the first shell, and the molar concentration of manganese in the first core is lower than that in the first shell. The first shell also includes a doping element M, which includes at least four of Zr, Cr, Al, W, Ta, Mg, Ca, Ti, Mo, Nb, and B. The first coating layer comprises a metal compound and a fluoride; The second coating layer includes a boride.

2. The low-strain, high-stability, low-pressure cathode material according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The general structural formula of the core-shell cathode material is: Li a Ni x Co y Mn z M w O2, where 1.02≤a≤1.2, 0.6≤x≤1, 0≤y≤0.2, 0≤z≤0.2, 0 <w≤0.4,x+y+z+w=1; (2) The mass fraction of nickel in the first core in the core-shell cathode material is 24-58%; (3) The mass fraction of nickel in the first outer shell in the core-shell cathode material is 0.3-22%; (4) The cell volume expansion of the low-strain, high-stability, low-pressure cathode material is 0.05%-0.8%; (5) The core-shell cathode material further includes a cavity, which accounts for 0.2%-13% of the total volume of the core-shell cathode material.

3. The low-strain, high-stability, low-pressure cathode material according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The diameter of the first core is 1.1-3.18 μm; (2) The thickness of the first outer shell is 0.01-0.25 μm; (3) The thickness of the first coating layer is 30-170 nm; (4) The thickness of the second coating layer is 1-65 μm; (5) The particle size of the low strain, high stability and low pressure cathode material is 100-500 mesh.

4. A method for preparing a low-strain, high-stability, low-pressure cathode material as described in any one of claims 1-3, characterized in that, include: A core-shell precursor is provided, the core-shell precursor comprising a second core and a second shell disposed on the surface of the second core, wherein the molar concentration of nickel in the second core is higher than that in the second shell, and the molar concentration of manganese in the second core is lower than that in the second shell; Under an oxygen-containing atmosphere, the core-shell precursor and the M-containing additive are first mixed and first sintered to obtain a first sintered product. Under an oxygen-containing atmosphere, the first sintered product and the first lithium salt are mixed and sintered a second time to obtain the second sintered product. Under an oxygen-containing atmosphere, the second sintered product and the second lithium salt are mixed and sintered in a third manner to obtain the third sintered product. Under an oxygen-containing atmosphere, the third sintering product, the transition metal compound, and the fluorine-containing compound are mixed and sintered in a fourth manner to obtain a fourth sintering product. The fourth sintering product and the boride are mixed and sintered in a fifth process to obtain a low-strain, high-stability, low-pressure cathode material.

5. The method for preparing the low-strain, high-stability, low-pressure cathode material according to claim 4, characterized in that, At least one of the following conditions must be met: (1) The M-containing additive includes at least one of the following: oxides, hydroxides, carbonate compounds, halides, sulfides and phosphate compounds containing M; (2) The first lithium salt and the second lithium salt each independently include at least one of lithium carbonate, lithium hydroxide, lithium oxide, lithium sulfide and lithium methyl; (3) The transition metal compound includes at least one of ammonium tungstate, tungsten trioxide, manganese carbonate, manganese oxide, manganese tetroxide, lithium tungstate, molybdenum trioxide, ammonium molybdate, titanium dioxide, cobalt tetroxide, cobalt hydroxyl oxide, cobalt oxide, aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, niobium pentoxide, niobic acid, lanthanum oxide, antimony oxide, cerium oxide, tellurium oxide, niobic acid, lithium niobate, and yttrium oxide; (4) The fluorine-containing compound includes at least one of lithium fluoride, aluminum fluoride, ammonium fluoride, ammonium hydrogen fluoride, magnesium fluoride and calcium fluoride; (5) The borides include at least one of boric acid, zirconium boride, lithium borate, boron oxide, lithium thioborate, boron nitride, lithium tetraborate, lithium metaborate, lithium triborate and titanium boride; (6) The D50 of the core-shell precursor is 1.4-3.4 μm, the diameter of the second core is 0.9-3.38 μm, the thickness of the second shell is 0.01-0.25 μm, the mass fraction of nickel in the second core in the core-shell cathode material is 24-58%, and the mass fraction of nickel in the second shell in the core-shell cathode material is 0.3-22%.

6. The method for preparing the low-strain, high-stability, low-pressure cathode material according to claim 4, characterized in that, At least one of the following conditions must be met: (1) The additive containing M accounts for 500-3000 ppm of the total material in the first mixture; (2) The molar ratio of the transition metal to the first lithium salt in the first sintered product is 1:a', and 0.612≤a'<1.2; (3) The molar ratio of the transition metal to the second lithium salt in the second sintered product is 1:a'', 0 <a''≤0.588; (4) The transition metal compound accounts for 500-15000 ppm of the total material of the fourth mixture, and the fluorine-containing compound accounts for 500-10000 ppm of the total material of the fourth mixture; (5) The boride accounts for 500-2000 ppm of the total material of the fifth mixture.

7. The method for preparing the low-strain, high-stability, low-pressure cathode material according to claim 4, characterized in that, At least one of the following conditions must be met: (1) The heating rate of the first sintering is 1-8℃ / min, the final temperature is 450-800℃, the holding time is 6-12h, and the cooling rate is 1-8℃ / min; (2) The second sintering includes sequential low-temperature sintering and high-temperature sintering; the heating rate of the low-temperature sintering is 1-10℃ / min, the final temperature is 250-550℃, and the holding time is 1-16h; the heating rate of the high-temperature sintering is 1-8℃ / min, the final temperature is 500-800℃, the holding time is 4-24h, the cooling rate is 1-8℃ / min, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; (3) The heating rate of the third sintering is 5-15℃ / min, the final temperature is 700-900℃, the isothermal time is 1-12h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 90%-100%; (4) The heating rate of the fourth sintering is 2-6℃ / min, the final temperature is 500-750℃, the isothermal time is 4-16h, and the gas flow rate is 8-30m. 3 / h, with an oxygen content of 95%-100%; (5) The heating rate of the fifth sintering is 2-8℃ / min, the final temperature is 200-350℃, and the holding time is 1-16h.

8. A positive electrode sheet, characterized in that, Including the low-strain, high-stability, low-pressure cathode material as described in any one of claims 1-3.

9. A solid-state battery, characterized in that, Includes the positive electrode sheet as described in claim 8.

10. An electrical appliance, characterized in that, Includes the solid-state battery as described in claim 9.

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