Solid-state battery and preparation method thereof, doped / coated modified oxide-based positive electrode active material, positive electrode sheet, and electric device

Abstract

This application relates to a solid-state battery and its fabrication method, a doped / coated modified oxide-based positive electrode active material, a positive electrode sheet, and an electrical device. The solid-state battery includes a positive electrode active layer comprising a doped / coated modified oxide-based positive electrode active material and a sulfide solid electrolyte. The doped / coated modified oxide-based positive electrode active material includes a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body. The positive electrode active body includes a doped oxide-based positive electrode active material, which includes a dopant element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material, including an oxide-type oxygen-absorbing material. This solid-state battery exhibits significantly improved cycle performance.

Description

Technical Field

[0001] This application relates to the field of solid-state battery technology, and further to a solid-state battery and its preparation method, a doped / coated modified oxide positive electrode active material, a positive electrode sheet, and an electrical device. Background Technology

[0002] The statements herein are provided only as background information in connection with this application and do not necessarily constitute prior art.

[0003] Solid-state batteries, represented by all-solid-state batteries, have attracted much attention due to their excellent energy density. Solid electrolyte materials are used to improve the solid-phase transport of active ions in solid-state batteries and are one of the core components. Among the many solid electrolyte materials currently available, sulfide solid electrolytes possess extremely high ionic conductivity (e.g., 1 mS / cm to 10 mS / cm at room temperature) and excellent mechanical properties, making them a favored solid electrolyte material in solid-state battery technology. However, the cycle performance of solid-state batteries that simultaneously incorporate oxide-based positive electrode active materials and sulfide solid electrolytes at the positive electrode is not ideal. Summary of the Invention

[0004] According to various embodiments and examples of this application, this application provides a solid-state battery and its preparation method, a doped / coated modified oxide-based positive electrode active material, a positive electrode sheet, and an electrical device, which have significantly improved cycle performance.

[0005] In a first aspect of this application, a solid-state battery is provided, comprising a positive electrode active layer, the positive electrode active layer comprising a doped / coated modified oxide-based positive electrode active material and a sulfide solid electrolyte, the doped / coated modified oxide-based positive electrode active material comprising a dopant element and a coating layer, the coating layer comprising a carbon composite oxygen-absorbing material. Furthermore, the carbon composite oxygen-absorbing material is a composite material based on a carbon conductive material and an oxygen-absorbing material, the oxygen-absorbing material comprising an oxide-type oxygen-absorbing material. This solid-state battery exhibits significantly improved cycle performance.

[0006] In some embodiments, a solid-state battery is provided, which includes a positive electrode layer, the positive electrode layer including a positive electrode active layer, the positive electrode active layer including a positive electrode active material and a positive electrode electrolyte material, the positive electrode electrolyte material including a sulfide solid electrolyte;

[0007] The positive electrode active material includes a doped / coated modified oxide positive electrode active material, which includes a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body. The positive electrode active body includes a doped oxide positive electrode active substance, which includes a doping element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material. The oxygen-absorbing material includes an oxide-type oxygen-absorbing material.

[0008] Introducing doped / coated modified oxide-based positive electrode active materials into the positive electrode active layer containing a sulfide solid electrolyte, these materials undergo both doping and coating modifications. The coating layer includes a carbon composite oxygen-absorbing material, primarily composed of carbon conductive materials and oxygen-absorbing materials, including oxide-type oxygen-absorbing materials. This approach allows for the regulation of the electronic structure of the positive electrode active body by doping elements, improving its lattice stability and suppressing oxygen release from the oxide-based active material. Furthermore, the coating layer prevents direct contact between the oxide-based active material and the sulfide solid electrolyte. The introduced oxide-type oxygen-absorbing material in the coating layer further reduces the impact of lattice oxygen release from the positive electrode active body on the sulfide solid electrolyte. The oxygen-absorbing material exhibits excellent high-voltage resistance and can more stably perform its oxygen-absorbing function at high cathode potentials. Furthermore, by combining the oxygen-absorbing material with carbon conductive material, the overall electronic conductivity of the coating layer containing the oxygen-absorbing material can be improved, suppressing or preventing the oxygen-absorbing material in the coating layer from affecting the cathode capacity. Through the aforementioned multiple effects, the structural stability of the cathode active material can be significantly improved, the oxidative decomposition of the sulfide solid electrolyte by the lattice oxygen release of the cathode active material can be significantly suppressed, the structural stability and ion-conducting stability of the sulfide solid electrolyte in the cathode active layer can be significantly improved, the interfacial stability between the sulfide solid electrolyte and the cathode active material can be significantly improved, the cathode interfacial impedance can be reduced, the cathode capacity can be promoted, and the cycle performance of the solid-state battery can be significantly improved.

[0009] In some embodiments, the doping element includes one or more of cerium, iron, titanium, copper, and zirconium, and the oxygen-absorbing material includes one or more of cerium oxide, iron oxide, titanium oxide, and yttrium barium copper oxide (YBCO).

[0010] By selecting the aforementioned types of doping elements and oxygen-absorbing materials and incorporating them into the lattice of the positive electrode active body, the appropriate ion size of the doping elements can promote the generation of lithium vacancies and change the electronic structure, thereby enhancing lithium-ion migration kinetics. In addition, by utilizing the variable valence state characteristics of doping elements such as cerium, iron, titanium, copper, and zirconium, electron transfer can occur within the lattice, potentially generating oxygen vacancies and suppressing electron localization. These doping elements can better regulate the electronic structure of the positive electrode active body and better stabilize the lattice of the positive electrode active body. These oxygen-absorbing materials, while possessing good oxygen absorption capacity, also have better high-voltage resistance, and can more stably exert their oxygen absorption effect. This is beneficial for better improving the structural stability and ion conduction stability of sulfide solid electrolytes, better promoting the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0011] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0012] (a1) The mass percentage of the oxide-type oxygen-absorbing substance relative to the oxygen-absorbing substance in the carbon composite oxygen-absorbing material is 80% to 100%;

[0013] (a2) The oxygen-absorbing substance includes cerium oxide (CeO). 2-δ1 The cerium oxide CeO 2-δ1 The oxygen vacancy index δ1 is 0–0.5;

[0014] (a3) The oxygen-absorbing substance includes iron oxide Fe2O 3-δ2 The iron oxide Fe2O 3-δ2 The oxygen vacancy index δ2 is 0–0.7;

[0015] (a4) The oxygen-absorbing substance includes titanium oxide (TiO2). 2-δ3 The titanium oxide TiO 2-δ3 The oxygen vacancy index δ3 ranges from 0 to 0.25.

[0016] (a5) The oxygen-absorbing substance includes yttrium barium copper oxide (YBa2Cu3O). 7-δ4 The yttrium barium copper oxide YBa2Cu3O 7-δ4 The oxygen vacancy index δ4 is 0 to 0.5.

[0017] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0018] (a1') The mass percentage of the oxide-type oxygen-absorbing substance relative to the oxygen-absorbing substance in the carbon composite oxygen-absorbing material is 90% to 100%;

[0019] (a2') The oxygen-absorbing substance includes cerium oxide (CeO). 2-δ1 The cerium oxide CeO 2-δ1 The oxygen vacancy index δ1 ranges from 0 to 0.35.

[0020] (a3') The oxygen-absorbing substance includes iron oxide Fe2O 3-δ2 The iron oxide Fe2O 3-δ2 The oxygen vacancy index δ2 is 0–0.2;

[0021] (a4') The oxygen-absorbing substance includes titanium oxide (TiO2). 2-δ3 The titanium oxide TiO 2-δ3 The oxygen vacancy index δ3 is 0–0.2;

[0022] (a5') The oxygen-absorbing substance includes yttrium barium copper oxide (YBa2Cu3O). 7-δ4 The yttrium barium copper oxide YBa2Cu3O 7-δ4 The oxygen vacancy index δ4 is 0 to 0.1.

[0023] By controlling the mass ratio of oxide-type oxygen absorbers to oxygen absorbers in carbon composite oxygen absorbers (F... O1 Within the aforementioned range, the better stability of oxide-type oxygen-absorbing materials at high oxidation potentials of the positive electrode can better leverage the oxygen absorption effect of carbon composite oxygen-absorbing materials, which is more conducive to improving the structural stability of sulfide solid electrolytes, and more conducive to promoting the capacity utilization of the positive electrode and significantly improving the cycle performance of solid-state batteries.

[0024] By controlling the oxygen-absorbing substances to be the aforementioned types, it is beneficial to provide better oxygen absorption.

[0025] In some embodiments, at least one of the doping element and the oxide-type oxygen absorber includes cerium.

[0026] In some embodiments, the doping element includes cerium, and the oxygen-absorbing material includes cerium oxide;

[0027] Optionally, the cerium oxide includes cerium oxide (CeO2).

[0028] In some embodiments, the oxygen-absorbing material includes cerium oxide, wherein the cerium oxide accounts for 80% to 100% of the mass percentage of the oxygen-absorbing material in the carbon composite oxygen-absorbing material, and optionally 90% to 100%.

[0029] Cerium doping can better control the electronic structure of the positive electrode active body; in addition, based on the radius size characteristics of cerium ions, after cerium element is doped into the lattice of the positive electrode active body, it can form strong chemical bonds with the surrounding oxygen, such as Ce-O bonds, which can enhance the binding force of the lattice to oxygen, improve lattice stability, suppress oxygen release, and significantly improve the cycle performance of solid-state batteries.

[0030] Cerium oxide has good oxygen adsorption properties, providing abundant oxygen vacancies. It also has good high voltage resistance, which can provide better oxygen absorption and significantly improve the cycle performance of solid-state batteries.

[0031] Controlling the cerium dopant element in the positive electrode active body to be the same cerium element present in the cerium oxide in the coating layer is beneficial to more uniformly disperse the internal stress generated by the lattice during charging and discharging, which is more conducive to further improving the structural stability of oxide-based positive electrode active materials and further suppressing oxygen release; thus, the cycle performance of solid-state batteries can be significantly improved.

[0032] Compared to other types of cerium oxides, cerium oxide has higher pressure resistance, better stability, and is simpler to prepare.

[0033] In some embodiments, the doping element and the oxide-type oxygen absorber comprise at least one of the same elements.

[0034] By controlling the doping elements in the positive electrode active body to include at least one of the same elements as the carbon composite oxygen-absorbing material, the bulk phase and coating layer of the positive electrode active body contain the same type of elements. This is beneficial for more uniformly dispersing the internal stress generated by the lattice during charging and discharging, further improving the structural stability of oxide-based positive electrode active materials, suppressing oxygen release, further improving the structural stability and ion-conducting effect of sulfide solid electrolytes, better improving the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0035] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0036] (b1) The mass percentage of the doping element in the positive electrode active body is 0.1% to 5%;

[0037] (b2) At least a portion of the dopant elements are located on the surface of the positive electrode active body; optionally, the dopant elements in the positive electrode active body are located at a distance of 0 to 50 nm from the outer surface of the positive electrode active body.

[0038] (b3) The doping element includes cerium, and the mass percentage of the cerium doping element in the positive electrode active body is 0.1% to 5%.

[0039] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0040] (b1') The mass percentage of the doping element in the positive electrode active body is 0.1% to 2%;

[0041] (b2') The doping element in the positive electrode active body is located at a distance of 0-5 nm from the outer surface of the positive electrode active body;

[0042] (b3') The doping element includes cerium, and the mass percentage of the cerium doping element in the positive electrode active body is 0.1% to 2%.

[0043] When at least some of the doping elements are located on the surface of the positive electrode active body, the electronic structure of the positive electrode active body surface can be better regulated, and surface oxygen release can be suppressed. Moreover, the doping elements located on the surface of the positive electrode active body can have a better synergistic effect with the same elements in the carbon composite oxygen-absorbing material of the coating layer, and better disperse internal stress. Thus, the cycle performance of solid-state batteries can be significantly improved.

[0044] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0045] (c1) In the carbon composite oxygen-absorbing material, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 5%;

[0046] (c2) In the coating layer, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 5%;

[0047] (c3) The carbon composite oxygen-absorbing material has a mass percentage content of 80% to 100% in the coating layer;

[0048] (c4) The sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the coating layer is 80% to 100%.

[0049] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0050] (c1') In the carbon composite oxygen-absorbing material, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 2.5%;

[0051] (c2') In the coating layer, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 2.5%;

[0052] (c3') The carbon composite oxygen-absorbing material has a mass percentage content of 80% to 100% in the coating layer;

[0053] (c4') The sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the coating layer is 80% to 100%.

[0054] By controlling the mass percentage (R) of carbon conductive material relative to oxygen-absorbing material in the neutralization and / or coating layer of carbon composite oxygen-absorbing material. 10 and / or R 11 This approach helps to better balance the oxygen absorption capacity of oxygen-absorbing materials, the electron transport capacity of carbon conductive materials, and the synergistic effect of doping elements and the same elements in oxide-type oxygen-absorbing materials. It also helps to better improve the structural stability of positive electrode active materials, the structural stability of sulfide solid electrolytes, the overall conductivity of the coating layer, the contact stability and chemical stability of the positive electrode interface, and thus better promote the utilization of positive electrode capacity and significantly improve the cycle performance of solid-state batteries.

[0055] By adjusting the mass percentage (F) of the carbon composite oxygen-absorbing material in the coating layer 21 The sum of the mass percentages of carbon conductive material and oxygen-absorbing material in the coating layer (F) 22 If one or two of the parameters are within the aforementioned range, it is beneficial to control the coating amount within a more suitable range, thereby better promoting the positive electrode capacity and significantly improving the cycle performance of solid-state batteries.

[0056] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0057] (d1) The carbon composite oxygen-absorbing material accounts for 0.5% to 5% of the mass of the doped / coated modified oxide-based positive electrode active material;

[0058] (d2) The coating layer accounts for 0.5% to 5% of the mass of the doped / coated modified oxide cathode active material;

[0059] (d3) The carbon composite oxygen-absorbing material includes carbon composite cerium oxide, wherein the carbon composite cerium oxide accounts for 0.5% to 5% of the mass of the doped / coated modified oxide positive electrode active material;

[0060] (d4) The average thickness of the coating layer is 5 nm to 60 nm;

[0061] (d5) At least a portion of the coating layer has a thickness of 5 nm to 60 nm.

[0062] In some embodiments, the doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics:

[0063] (d1') The carbon composite oxygen-absorbing material accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material;

[0064] (d2') The coating layer accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material;

[0065] (d3') The carbon composite oxygen-absorbing material includes carbon composite cerium oxide, wherein the carbon composite cerium oxide accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material;

[0066] (d4') The average thickness of the coating layer is 15nm to 40nm;

[0067] (d5') ​​At least a portion of the coating layer has a thickness of 15nm to 40nm.

[0068] By adjusting the mass ratio (F) of carbon composite oxygen-absorbing material in doped / coated modified oxide-based positive electrode active materials 20 ), the mass percentage of the coating layer in doped / coated modified oxide cathode active materials (F) 10 One or more parameters, such as the average thickness (D1) of the coating layer, are beneficial for controlling the coating amount within a more suitable range. This allows for a better balance between the oxygen absorption capacity of the oxygen-absorbing material, the role of the carbon conductive material in improving the electron transport rate, the synergistic effect of the dopant element and the same element in the oxide-type oxygen-absorbing material, and the ion transport between the positive electrode active material and the positive electrode electrolyte material. This is beneficial for comprehensively improving the structural stability of the positive electrode active material, the structural stability of the sulfide solid electrolyte, the interfacial impedance caused by the coating layer, the contact stability and chemical stability of the positive electrode interface, and thus better promoting the utilization of the positive electrode capacity and significantly improving the cycle performance of the solid-state battery.

[0069] In some embodiments, the carbon composite oxygen-absorbing material satisfies one or more of the following characteristics:

[0070] (e1) The carbon conductive material includes one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene.

[0071] (e2) The carbon conductive material is nanoparticles. Optionally, the average particle size of the carbon conductive material is 5 nm to 0.21 μm. The average particle size refers to the average of the maximum particle size of each particle. The maximum particle size refers to the maximum diameter among the diameters of the particles in all directions.

[0072] (e3) The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected as 1 nm to 0.5 μm;

[0073] (e4) The oxygen-absorbing material is nanoparticles, and optionally, the average particle size of the oxygen-absorbing material is 8nm to 50nm.

[0074] (e5) The maximum particle size of the oxygen-absorbing substance is less than or equal to 200 nm, and can be selected as 1 nm to 200 nm;

[0075] (e6) The oxygen-absorbing material includes nano-cerium oxide, wherein the average particle size of the nano-cerium oxide is 10 nm to 50 nm.

[0076] (e7) The oxygen-absorbing material includes nano-cerium oxide, wherein the maximum particle size of the nano-cerium oxide is less than or equal to 200 nm, and may be selected from 1 nm to 200 nm.

[0077] In some embodiments, the carbon composite oxygen-absorbing material satisfies one or more of the following characteristics:

[0078] (e1') The carbon conductive material includes vapor-grown carbon fibers;

[0079] (e2') The average particle size of the carbon conductive material is 30 nm to 0.1 μm;

[0080] (e3') The maximum particle size of the carbon conductive material is 8 nm to 0.5 μm, and can be selected as 50 nm to 0.3 μm;

[0081] (e4') The average particle size of the oxygen-absorbing substance is 10 nm to 20 nm;

[0082] (e5') The maximum particle size of the oxygen-absorbing substance is 5nm to 100nm;

[0083] (e6') The oxygen-absorbing material includes nano-cerium oxide, wherein the average particle size of the nano-cerium oxide is 10nm to 20nm;

[0084] (e7') The oxygen-absorbing material includes nano-cerium oxide, and the maximum particle size of the nano-cerium oxide can be selected from 5nm to 100nm.

[0085] By controlling one or more parameters of the size (average particle size and / or maximum particle size) of the carbon conductive material and the size (average particle size and / or maximum particle size) of the oxygen-absorbing material within the aforementioned smaller nanoscale range, the aggregation and adsorption characteristics of small-sized nanoparticles can be utilized to improve the bonding stability between the carbon conductive material and the oxygen-absorbing material in the carbon composite oxygen-absorbing material, as well as the bonding stability between the coating layer and the positive electrode active body. This is beneficial for improving the structural stability of the positive electrode active material, and also for more stably performing the function of isolating the direct contact of the sulfide solid electrolyte and inhibiting oxygen release, promoting a more stable performance of the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0086] In some embodiments, the doped oxide-type positive electrode active material has a layered crystal structure.

[0087] For oxide-based cathode active materials with layered crystal structures, the introduction of doped / coated modified oxide-based cathode active materials has a significant effect on improving the structural stability of the cathode active materials and inhibiting oxygen release.

[0088] In some embodiments, the positive electrode active body comprises a lithium transition metal oxide, and the doped oxide-type positive electrode active material is at least a portion of the lithium transition metal oxide; the positive electrode active body satisfies one or more of the following characteristics:

[0089] (f1) The lithium transition metal oxide includes lithium nickel-based oxide, which includes Li, non-lithium metal elements and O, and the non-lithium metal elements include Ni.

[0090] (f2) The lithium transition metal oxide has a layered crystal structure;

[0091] (f3) The lithium transition metal oxide accounts for 95% to 100% of the mass of the positive electrode active body.

[0092] By incorporating lithium transition metal oxides, it is beneficial to improve the energy density of solid-state batteries.

[0093] In some embodiments, the lithium transition metal oxide includes lithium nickel-based oxides;

[0094] The positive electrode active body satisfies one or more of the following characteristics:

[0095] (i1) The atomic molar ratio of Ni to non-lithium metal elements in the lithium nickel-based oxide is q1, where 0.8 ≤ q1 ≤ 0.95;

[0096] (i2) The lithium nickel-based oxide contains Ni and Li elements in an atomic molar ratio of q2:x2, wherein 0.8≤q2≤0.95 and 0.6≤x2≤1.2;

[0097] (i3) The lithium nickel-based oxide contains Ni and O elements in an atomic molar ratio of q3:x3, wherein 0.8≤q3≤0.95 and 1.6≤x3≤2.2;

[0098] (i4) The lithium nickel-based oxide contains Co, and the atomic molar ratio of Co to the non-lithium metal element in the lithium nickel-based oxide is q4, wherein 0.02≤q4≤0.15, and optionally 0.05≤q4≤0.15;

[0099] (i5) The lithium nickel-based oxide contains Mn element, and the atomic molar ratio of Mn element to non-lithium metal element in the lithium nickel-based oxide is q5, wherein 0.02≤q5≤0.15, and optionally 0.05≤q5≤0.15;

[0100] (i6) The lithium nickel-based oxide has a layered crystal structure;

[0101] (i7) The lithium nickel-based oxide accounts for 80% to 100% of the mass of the lithium transition metal oxide;

[0102] (i8) The lithium nickel-based oxide accounts for 80% to 100% of the mass of the positive electrode active body.

[0103] In some embodiments, the positive electrode active body satisfies one or more of the following characteristics:

[0104] (j1)0.81≤q1≤0.93;

[0105] (j2)0.81≤q2≤0.93;

[0106] (j3)0.8≤x2≤1.1;

[0107] (j4)0.81≤q3≤0.93;

[0108] (j5)1.8≤x3≤2.06;

[0109] (j6) The lithium nickel-based oxide contains Co, where 0.08 ≤ q4 ≤ 0.1;

[0110] (j7) The lithium nickel-based oxide contains Mn element, 0.08≤q5≤0.1;

[0111] (j8) The lithium nickel-based oxide accounts for 90% to 100% of the mass of the lithium transition metal oxide;

[0112] (j9) The lithium nickel-based oxide accounts for 90% to 100% of the mass of the positive electrode active body;

[0113] (j10) The lithium transition metal oxide includes lithium nickel cobalt manganese-based oxides; optionally, in the lithium nickel cobalt manganese-based oxide, the ratio of the sum of the atomic molar ratios of nickel, cobalt, and manganese to the sum of the atomic molar ratios of non-lithium metal elements is denoted as R. NCM R NCM The value is 0.9 to 1; further optionally, R NCM It ranges from 0.96 to 1.

[0114] For the aforementioned types of lithium transition metal oxides (such as lithium nickel-based oxides with high nickel content), the introduction of doped / coated modified oxide cathode active materials has a significant effect on improving the structural stability of the cathode active material and suppressing oxygen release.

[0115] In some embodiments, the sulfide solid electrolyte includes one or more of LGPS-type sulfide electrolytes, binary sulfide electrolytes, and ternary sulfide electrolytes;

[0116] The binary sulfide electrolyte includes one or more of the following: Li2S-GeS2 binary sulfide, Li2S-P2S5 binary sulfide, Li2S-SiS2 binary sulfide, and Li2S-B2S3 binary sulfide.

[0117] The ternary sulfide electrolyte includes silver sulfide-germanium sulfide electrolyte and Li2S-M. 5 S2-P2S5 ternary sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, Li2S-P2S5-M 6 S-ternary sulfide electrolyte, Li2S-P2S5-M 6 Cl is one or more of a ternary sulfide electrolyte and a thio-LISICON type sulfide electrolyte; M 5 Includes one or more elements from Si, Ge, Sn, and Al; M 6 It includes one or more elements selected from Ge, Al, Sn, Pb, Sb, Si, and As.

[0118] In some embodiments, the positive electrode active layer satisfies one or more of the following characteristics:

[0119] (g1) The doped / coated modified oxide cathode active material accounts for 80% to 100% of the mass of the cathode active material;

[0120] (g2) The mass percentage of the doped / coated modified oxide cathode active material in the cathode active layer is 70% to 95%;

[0121] (g3) The sulfide solid electrolyte in the positive electrode active layer has a mass percentage content of 5% to 30%;

[0122] (g4) The sulfide solid electrolyte accounts for 80% to 100% of the mass of the positive electrode electrolyte material.

[0123] In some embodiments, the positive electrode active layer satisfies one or more of the following characteristics:

[0124] (g1') The doped / coated modified oxide cathode active material accounts for 90% to 100% of the mass of the cathode active material;

[0125] (g2') The doped / coated modified oxide cathode active material has a mass percentage content of 75% to 90% in the cathode active layer;

[0126] (g3') The sulfide solid electrolyte in the positive electrode active layer has a mass percentage content of 10% to 30%;

[0127] (g4') The sulfide solid electrolyte accounts for 90% to 100% of the mass of the positive electrode electrolyte material.

[0128] In some embodiments, the solid-state battery satisfies one or more of the following characteristics:

[0129] (h1) The solid-state battery is an all-solid-state battery;

[0130] (h2) The solid-state battery is a lithium-ion secondary battery, which can be selected as an all-solid-state lithium-ion secondary battery.

[0131] In a second aspect of this application, a doped / coated modified oxide-based positive electrode active material is provided, which includes the characteristics of the doped / coated modified oxide-based positive electrode active material in solid-state batteries described in the first aspect of this application.

[0132] In a third aspect of this application, a positive electrode sheet is provided, which includes a positive active layer, the positive active layer comprising the characteristics of a positive active layer in a solid-state battery as described in the first aspect of this application.

[0133] In a fourth aspect of this application, a method for preparing a solid-state battery is provided, comprising the following steps: stacking a positive electrode, a solid electrolyte material layer and a negative electrode in sequence, pressing them together to prepare a solid-state battery;

[0134] The positive electrode includes a positive active layer, which comprises a positive active material and a positive electrolyte material. The positive electrolyte material includes a sulfide solid electrolyte. The positive active material includes a doped / coated modified oxide-based positive active material, which comprises a positive active body and a coating layer located on at least a portion of the surface of the positive active body. The positive active body includes a doped oxide-based positive active material, which includes a doping element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material. The oxygen-absorbing material includes an oxide-type oxygen-absorbing material. The solid electrolyte raw material layer comprises a solid electrolyte material.

[0135] In some embodiments, the positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery described in the first aspect of this application.

[0136] In some embodiments, the doped / coated modified oxide-based positive electrode active material is prepared by a method comprising the following steps:

[0137] The oxide-based positive electrode active material raw material and the dopant source are ultrasonically dispersed, stirred, and dried in a first solvent to remove the first solvent, thereby obtaining a preliminary mixture; the preliminary mixture is then annealed in an oxygen-containing atmosphere to prepare the doped oxide-based positive electrode active material; wherein, the dopant source includes the dopant element;

[0138] The doped oxide-type positive electrode active material is prepared by dry ball milling and mixing with the carbon composite oxygen-absorbing material.

[0139] In some embodiments, the method for preparing the solid-state battery satisfies one or more of the following characteristics:

[0140] (k1) The first solvent includes one or more of ethanol, toluene, methanol and dimethyl ether;

[0141] (k2) The rotation speed for the dry ball milling mixture is 300 rpm to 600 rpm;

[0142] (k3) The ball milling time for the dry ball milling mixture is 12h to 36h;

[0143] (k4) The annealing temperature is 400℃~800℃;

[0144] (k5) The annealing process is performed for 2 hours to 12 hours;

[0145] (k6) The carbon composite oxygen-absorbing material is prepared by a method comprising the following steps: mixing carbon conductive material raw material and oxygen-absorbing material raw material in a second solvent, performing liquid-phase ball milling, and drying to remove the second solvent, thereby preparing the carbon composite oxygen-absorbing material; optionally, the second solvent includes one or more of ethanol, toluene, methanol, and dimethyl ether; optionally, the rotation speed of the liquid-phase ball milling is 300 rpm to 600 rpm, and the ball milling time is 12 h to 36 h;

[0146] (k7) The electronic conductivity of the carbon composite oxygen-absorbing material at 25℃ is ≥5mS / cm;

[0147] (k8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising the doped / coated modified oxide positive electrode active material and the sulfide solid electrolyte, and forming a film under solvent-free conditions; wherein, the positive electrode material composition may optionally include one or more of a binder and a conductive agent;

[0148] (k9) The solid-state battery described in the first aspect of this application is prepared.

[0149] Liquid-phase ball milling allows carbon conductive materials and oxygen-absorbing materials to be combined more effectively and stably.

[0150] In a fifth aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application, the doped / coated modified oxide-based positive electrode active material described in the second aspect of this application, the positive electrode sheet described in the third aspect of this application, and a solid-state battery prepared by the method for preparing a solid-state battery described in the fourth aspect of this application.

[0151] Details of one or more embodiments or examples of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0152] To better describe and illustrate the embodiments, examples, or models provided in this application, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed applications, the currently described embodiments, examples, or models, or the best mode of conduct of these applications as currently understood. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0153] Figure 1 This is a schematic diagram of a solid-state battery cell according to one embodiment of this application.

[0154] Figure 2 for Figure 1 An exploded view of a solid-state battery cell according to an embodiment of this application is shown.

[0155] Figure 3 This is a schematic diagram of a battery device according to one embodiment of this application.

[0156] Figure 4 This is a schematic diagram of a battery pack according to one embodiment of this application.

[0157] Figure 5 for Figure 4 An exploded view of a battery pack according to one embodiment of this application is shown.

[0158] Figure 6 This is a schematic diagram of an electrical device that uses a solid-state battery as a power source according to one embodiment of this application.

[0159] Explanation of reference numerals in the attached figures:

[0160] 1. Battery pack; 2. Upper casing; 3. Lower casing; 4. Battery assembly; 5. Solid-state battery cell; 51. Housing; 52. Solid-state battery cell; 53. Cover plate; 6. Electrical device. Detailed Implementation

[0161] The following describes in detail, with appropriate reference to the accompanying drawings, some embodiments of the solid-state battery and its preparation method, doped / coated modified oxide-based positive electrode active material, positive electrode sheet, and electrical device of this application. However, some unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0162] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints. Any endpoint can be included or excluded independently and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0" and "5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when describing a parameter as an integer ≥ 2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 for that parameter. For instance, when describing a parameter as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0163] In this application, the term "numerical value" includes the number itself and its reasonable approximations. The definition of "numerical value" can apply to discrete numerical points or to the endpoints of a numerical range. Unless otherwise specified, the term "approximation" covers a numerical interval based on a reasonable range of fluctuations of the number itself. This reasonable range of fluctuations can vary depending on the type and magnitude of the number. This reasonable range of fluctuations can be reasonably determined based on the accuracy of the testing or measurement method. Therefore, when referring to a numerical value or a numerical range, unless otherwise specified, it should be understood that the numerical value includes its reasonable approximation, and the numerical range includes reasonable approximations at both endpoints. Those skilled in the art will understand that acceptable fluctuation ranges of the relevant approximations can be included within the definition of the numerical value or the numerical range. In this application, unless otherwise specified, "N1" can be reasonably understood as "about N1," and "N1~N2" can be reasonably understood as "about N1 to about N2," where N1 and N2 are two unequal numerical values.

[0164] In this application, unless otherwise specified, "about" means within a reasonable range above and below the stated number, and the range of fluctuation may vary depending on the type and value of the stated number. For example, a range of ±10%, ±5%, ±2%, ±1%, etc., may be allowed. For example, taking "about 20°C" and its approximation as ±1°C, approximate values ​​such as 19°C, 19.5°C, etc., within the approximation range indicated by "about 20°C" should also be included in the range indicated by "about 20°C".

[0165] In this application, the terms "multiple," "various," "multiple items," "several," etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more (greater than or equal to) two. It can be understood that when "any number of" items are involved, it refers to any suitable combination of multiple items, that is, a combination of "any number of" items in a manner that does not conflict and enables the implementation of this application.

[0166] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0167] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. The term "implementation" as used herein has a similar understanding.

[0168] Those skilled in the art will understand that, unless otherwise specified, the order in which the steps are written in the various embodiments or methods of this application does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but are preferably performed sequentially. For example, if method M includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, method M may also include step (c), meaning that step (c) can be added to method M in any order. For example, method M may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0169] In this application, open-ended technical features or solutions described using terms such as "containing," "comprising," or "including" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if 'a' includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both features or solutions where "a consists of a1, a2, and a3" or "a is selected from a1, a2, and a3," and features or solutions where "a includes not only a1, a2, and a3, but also other members."

[0170] In this application, unless otherwise specified, M (e.g., m1) means that m1 is a non-limiting example of M, and it is understood that M is not limited to m1.

[0171] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "with" or "without." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. Unless otherwise specified, the descriptions such as "optionally include" and "optionally contain" in this application, taking "optionally include" as an example, mean "may include or not include."

[0172] In this application, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. Any and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "M and / or N" represents the group consisting of M, N, and "a combination of M and N". "Containing M and / or N" can mean "containing M, containing N, and containing both M and N", or "containing M, containing N, or containing both M and N", and can be appropriately understood according to the context.

[0173] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0174] In this document, the term "suitable" in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the technical solution that enables the implementation of this application.

[0175] In this article, terms such as "preferred," "better," "more suitable," "ideal," "good," and "superior" are merely descriptions of implementation methods or examples that yield better results.

[0176] It should be understood that this does not constitute a limitation on the scope of protection of this application. If multiple "preferred options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred option" shall be independent.

[0177] In this application, terms such as "further," "even more," "especially," "for example," "as," "example," and "exemplary" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0178] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," and "fifth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," and "fifth" etc. serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0179] In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In this application, unless otherwise expressly specified and limited, the phrase "above" or "below" the second feature can indicate a horizontal positional relationship, or it can simply indicate the existence of an attachment relationship without specifying a horizontal positional relationship.

[0180] In this application, the term "room temperature" generally refers to 4℃ to 35℃, and may refer to 20℃ ± 5℃. In some embodiments or examples of this application, room temperature refers to 20℃ to 30℃.

[0181] In this application, when a unit is specified for a data range, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 3~5 h or 3-5 h both mean that the unit for the left endpoint "3" and the right endpoint "5" is h (hours), and both have the same meaning as 3h~5h. Furthermore, similar descriptions of other parameters such as temperature and size are interpreted in the same way.

[0182] In this application, the exemplary descriptions such as "in some implementations (or embodiments)" and "in one implementation (or embodiment)" may cover, but are not limited to, the following meanings: these solutions can be combined with other solutions in a suitable manner to form new technical solutions.

[0183] Unless otherwise stated, the improvements described in this application are not intended to be limited to any theoretical constraints.

[0184] For any test method for a certain parameter described in this application, as long as the test result of at least one test method is within the described range, it can be included in the protection scope of this application.

[0185] Solid-state batteries do not use a traditional liquid electrolyte. The component particles in a solid-solid contact system rely heavily on this interfacial contact for active ion transport. However, voids inevitably exist between the component particles in solid-state batteries, which can hinder interfacial charge transport. This solid-solid interface problem limits the performance of solid-state batteries, leading to issues such as poor cycle stability. Solid electrolyte materials are crucial for improving the solid-phase transport of active ions in solid-state batteries. Among the many solid electrolyte materials available, sulfide solid electrolytes are favored for their extremely high ionic conductivity (e.g., 1 mS / cm to 10 mS / cm at room temperature) and excellent mechanical properties. However, solid-state batteries that simultaneously incorporate oxide-based positive electrode active materials and sulfide solid electrolytes do not exhibit ideal cycle performance. During charge-discharge cycles, oxide-based positive electrode active materials may release oxygen, which in turn leads to the oxidation and decomposition of sulfide solid electrolytes, deteriorating the ion-conducting performance of sulfide solid electrolytes and causing serious interface problems. This severely affects the performance of such solid-state batteries, such as the deterioration of cycle performance, discharge capacity, and rate performance.

[0186] According to various embodiments and examples of this application, this application provides a solid-state battery and its preparation method, a doped / coated modified oxide-based positive electrode active material, a positive electrode sheet, and an electrical device, which have significantly improved cycle performance.

[0187] In some embodiments, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0188] In this application, "layered arrangement" refers to the description of the stacking direction between layered structures. For example, "including structural layer A and structural layer B in a layered arrangement" means that the stacking direction of structural layer A and structural layer B is along their respective layer thickness directions, that is, the thickness direction of structural layer A and the thickness direction of structural layer B are the same or substantially the same.

[0189] Unless otherwise specified, the term "solid-state battery" in this application refers to a battery in which the electrolyte includes a solid electrolyte material. Typically, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. During charging and discharging, active ions repeatedly insert and extract between the positive and negative electrode layers. The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers and also isolates them, preventing short circuits. Therefore, a separator, as found in traditional lithium-ion batteries, is not required in solid-state batteries. Solid-state batteries use a non-flammable solid electrolyte instead of the organic electrolyte found in traditional liquid lithium-ion batteries. Solid-state batteries are better suited for high-energy-density positive and negative electrode materials and reduce system weight, which is beneficial for achieving both increased energy density and improved performance.

[0190] In this application, unless otherwise specified, "solid electrolyte material" refers to an electrolyte material or electrolyte substance that exists in solid form during the storage and fabrication of solid-state batteries and components constituting solid-state batteries, as well as during the operation of solid-state batteries. This is understood to include, but is not limited to, solid electrolyte materials existing in solid form at room temperature.

[0191] In this application, unless otherwise specified, "electrode layer" includes electrode active material. The electrode layer can be a positive electrode layer or a negative electrode layer. "Electrode active material" in the electrode layer refers to a material capable of reversibly inserting and extracting active ions. Unless otherwise specified, "negative electrode active material" refers to a material used in the negative electrode layer capable of reversibly inserting and extracting active ions; "positive electrode active material" refers to a material used in the positive electrode layer capable of reversibly extracting and inserting active ions. During solid-state battery charging, active ions are extracted from the positive electrode, pass through the solid electrolyte layer, and insert into the negative electrode; during solid-state battery discharging, active ions are extracted from the negative electrode and insert into the positive electrode. The active ions are not particularly limited; non-limitingly, the active ions can be lithium ions, corresponding to a lithium-ion solid-state battery.

[0192] In this application, unless otherwise specified, "electrode active layer" includes at least one of the positive active layer in the positive electrode layer and the negative active layer in the negative electrode layer. Depending on the specific circumstances, the electrode active layer may refer to either the positive active layer or the negative active layer. It is understood that the positive active layer includes the positive active material and may also be referred to as the "positive active material layer"; the negative active layer includes the negative active material and may also be referred to as the "negative active material layer".

[0193] In a first aspect of this application, a solid-state battery is provided, comprising a positive electrode active layer, the positive electrode active layer comprising a doped / coated modified oxide-based positive electrode active material and a sulfide solid electrolyte, the doped / coated modified oxide-based positive electrode active material comprising a dopant element and a coating layer, the coating layer comprising a carbon composite oxygen-absorbing material. Furthermore, the carbon composite oxygen-absorbing material is a composite material based on a carbon conductive material and an oxygen-absorbing material, the oxygen-absorbing material comprising an oxide-type oxygen-absorbing material. This solid-state battery exhibits significantly improved cycle performance.

[0194] By introducing doped / coated modified oxide-based positive electrode active materials into the positive electrode active layer containing a sulfide solid electrolyte, and by simultaneously doping and coating these materials, the coating layer includes a carbon composite oxygen-absorbing material. This carbon composite oxygen-absorbing material is mainly composed of a carbon conductive material and an oxygen-absorbing material. In this approach, the electronic structure of the positive electrode active body can be controlled by the doping elements, improving its lattice stability and suppressing oxygen release from the oxide-based positive electrode active material. Furthermore, the coating layer hinders direct contact between the oxide-based positive electrode active material and the sulfide solid electrolyte, and the oxygen-absorbing material introduced into the coating layer can further reduce lattice oxygen release from the positive electrode active body. The oxidation and decomposition of sulfide solid electrolytes are addressed. Furthermore, the combination of oxygen-absorbing materials and carbon conductive materials improves the overall electronic conductivity of the coating layer incorporating the oxygen-absorbing material, suppressing or preventing the oxygen-absorbing material in the coating layer from affecting the cathode capacity. Through these multiple effects, the structural stability of the cathode active material is significantly improved, the oxidative decomposition of sulfide solid electrolytes by lattice oxygen release from the cathode active material is significantly suppressed, the structural stability and ion-conducting stability of the sulfide solid electrolyte in the cathode active layer are significantly improved, the interfacial stability between the sulfide solid electrolyte and the cathode active material is significantly improved, the cathode interfacial impedance is reduced, the cathode capacity is promoted, and the cycle performance of solid-state batteries is significantly improved.

[0195] By controlling the oxygen-absorbing substances in carbon composite oxygen-absorbing materials, including oxide-type oxygen-absorbing substances, and utilizing the better stability of oxide-type oxygen-absorbing substances at high oxidation potentials of the positive electrode, the oxygen-absorbing effect of carbon composite oxygen-absorbing materials can be better utilized. This is more conducive to improving the structural stability of sulfide solid electrolytes, promoting the capacity utilization of the positive electrode, and significantly improving the cycle performance of solid-state batteries.

[0196] In some embodiments, a solid-state battery is provided, comprising a positive electrode active layer, the positive electrode active layer comprising a doped / coated modified oxide positive electrode active material and a sulfide solid electrolyte; the doped / coated modified oxide positive electrode active material comprises a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body, the positive electrode active body comprising a doped oxide positive electrode active material comprising a doping element, and the coating layer comprising a carbon composite oxygen-absorbing material.

[0197] In some embodiments, a solid-state battery is provided, comprising a positive electrode active layer, which includes a doped / coated modified oxide-based positive electrode active material and a sulfide solid electrolyte. The doped / coated modified oxide-based positive electrode active material includes a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body. The positive electrode active body includes a doped oxide-based positive electrode active material, which includes a dopant element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material, and the oxygen-absorbing material includes an oxide-type oxygen-absorbing material. This solid-state battery exhibits significantly improved cycle performance.

[0198] In some embodiments, a solid-state battery is provided, comprising a positive electrode layer, the positive electrode layer including a positive electrode active layer, the positive electrode active layer including a positive electrode active material and a positive electrode electrolyte material, the positive electrode electrolyte material including a sulfide solid electrolyte; the positive electrode active material including a doped / coated modified oxide-based positive electrode active material, the doped / coated modified oxide-based positive electrode active material including a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body, the positive electrode active body including a doped oxide-based positive electrode active material, the doped oxide-based positive electrode active material including a dopant element, the coating layer including a carbon composite oxygen-absorbing material, the carbon composite oxygen-absorbing material being a composite material based on a carbon conductive material and an oxygen-absorbing material, the oxygen-absorbing material including an oxide-type oxygen-absorbing material.

[0199] In this application, unless otherwise specified, "doped / coated modified oxide-based cathode active material" includes a cathode active body and a coating layer located on at least a portion of the surface of the cathode active body. The cathode active body includes a doped oxide-based cathode active material, which includes a dopant element. It is understood that the cathode active body includes a dopant element doped in the bulk phase. The doped / coated modified oxide-based cathode active material is an oxide-based cathode active material that is simultaneously doped and coated, and it includes both a dopant element and a coating element, with the dopant element located in the bulk phase and the coating element located in the coating layer.

[0200] Unless otherwise stated in this application, "oxide-based positive electrode active material" is an oxide-type positive electrode active material, which is different from other types of positive electrode active materials such as phosphate-type materials.

[0201] In this application, unless otherwise specified, "doped oxide-type positive electrode active material" refers to an oxide-type positive electrode active material containing doped elements. "Oxide-type positive electrode active material" is a type of oxide-based positive electrode active material.

[0202] In this application, unless otherwise specified, the "doping element" in the positive electrode active body is a non-lithium metal element that is different from the bulk element. "Non-lithium metal element" refers to a metal element that is different from lithium.

[0203] In this application, unless otherwise specified, the “coating layer” in doped / coated modified oxide cathode active materials includes carbon composite oxygen-absorbing materials.

[0204] In this application, unless otherwise specified, "carbon composite oxygen-absorbing material" refers to a composite material based on a carbon conductive material and an oxygen-absorbing material. That is, the carbon composite oxygen-absorbing material is mainly composed of a carbon conductive material and an oxygen-absorbing material. Exemplarily, the sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the carbon composite oxygen-absorbing material can be greater than or equal to 80%, and can also be greater than or equal to any of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. Exemplarily, the sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the carbon composite oxygen-absorbing material can also be 90% to 100%, and can also be any of the following percentages or a range selected from any two of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0205] In this application, unless otherwise specified, "carbon conductive material" refers to a carbon material capable of transporting electrons. Carbon conductive materials may include, but are not limited to, traditional carbon conductive agents, and may also include carbon materials with good electronic conductivity, such as graphite. "Carbon material" refers to a substance based on the element carbon.

[0206] In this application, unless otherwise specified, "oxygen-absorbing substance" refers to a substance capable of absorbing and storing oxygen molecules or oxygen atoms. The oxygen absorption mechanism of an oxygen-absorbing substance may include, but is not limited to, one or more of the following: oxygen vacancies, physical adsorption, lattice oxygen participation, chemical bonding with oxygen, and consumption of oxygen through chemical reactions. Exemplarily, "oxide-type oxygen-absorbing substance" refers to an oxide-type oxygen-absorbing substance, which, unless otherwise specified, refers to a metal oxide-type substance. Oxide-type oxygen-absorbing substances can absorb external oxygen by utilizing the variable valence state of the contained metal element, oxygen vacancies, physical adsorption, and the dual covalent / ionic properties of the metal element. Non-limiting examples of oxide-type oxygen-absorbing substances may include one or more of cerium oxide, iron oxide, titanium oxide, and yttrium barium copper oxide (YBCO). In cerium oxides, the valence states of cerium (Ce) can include +3 and +4; in iron oxides, the valence states of iron (Fe) can include +2 and +3; in yttrium barium copper oxide (YBCO), the valence states of copper (Cu) can include +2 and +1; and in titanium oxides, the valence states of titanium (Ti) can include +3 and +4. When the metal element in an oxide-type oxygen absorber has a lower valence state, oxygen vacancies can be created, which is beneficial for providing better oxygen absorption capacity.

[0207] In some embodiments, the oxygen-absorbing material includes oxide-type oxygen-absorbing materials. Exemplarily, the total mass percentage of oxide-type oxygen-absorbing materials in the oxygen-absorbing material can be greater than or equal to 80%, and can also be greater than or equal to any of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. Exemplarily, the mass percentage of oxide-type oxygen-absorbing materials in the oxygen-absorbing material can also be 90% to 100%, and can also be any of the following percentages or a range selected from any two of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0208] In some embodiments, the carbon composite oxygen-absorbing material can be a composite material based on carbon conductive materials and oxide-type oxygen-absorbing materials. In this case, the carbon composite oxygen-absorbing material is mainly composed of carbon conductive materials and oxide-type oxygen-absorbing materials. Exemplarily, the sum of the mass percentages of the carbon conductive materials and oxygen-absorbing materials in the carbon composite oxygen-absorbing material can be greater than or equal to 80%, and can also be greater than or equal to any of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. Exemplarily, the sum of the mass percentages of the carbon conductive materials and oxide-type oxygen-absorbing materials in the carbon composite oxygen-absorbing material can also be 90% to 100%, and can also be any of the following percentages or a range selected from any two of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc. The composition of the carbon composite oxygen-absorbing material can also be found in the relevant description in the preparation method of the solid-state battery of the fourth aspect of this application.

[0209] Introducing doped / coated modified oxide-based positive electrode active materials into the positive electrode active layer containing a sulfide solid electrolyte, these materials undergo both doping and coating modifications. The coating layer includes a carbon composite oxygen-absorbing material, primarily composed of carbon conductive materials and oxygen-absorbing materials, including oxide-type oxygen-absorbing materials. This approach allows for the regulation of the electronic structure of the positive electrode active body by doping elements, improving its lattice stability and suppressing oxygen release from the oxide-based active material. Furthermore, the coating layer prevents direct contact between the oxide-based active material and the sulfide solid electrolyte. The introduced oxide-type oxygen-absorbing material in the coating layer further reduces the impact of lattice oxygen release from the positive electrode active body on the sulfide solid electrolyte. The oxygen-absorbing material exhibits excellent high-voltage resistance and can more stably perform its oxygen-absorbing function at high cathode potentials. Furthermore, by combining the oxygen-absorbing material with carbon conductive material, the overall electronic conductivity of the coating layer containing the oxygen-absorbing material can be improved, suppressing or preventing the oxygen-absorbing material in the coating layer from affecting the cathode capacity. Through the aforementioned multiple effects, the structural stability of the cathode active material can be significantly improved, the oxidative decomposition of the sulfide solid electrolyte by the lattice oxygen release of the cathode active material can be significantly suppressed, the structural stability and ion-conducting stability of the sulfide solid electrolyte in the cathode active layer can be significantly improved, the interfacial stability between the sulfide solid electrolyte and the cathode active material can be significantly improved, the cathode interfacial impedance can be reduced, the cathode capacity can be promoted, and the cycle performance of the solid-state battery can be significantly improved.

[0210] In this application, particle structure analysis methods such as transmission electron microscopy (TEM) can be used to detect and analyze whether the positive electrode active material has a coating layer. For example, instruments such as high-resolution transmission electron microscopy (HRTEM) can be used. Elemental analysis methods such as energy dispersive X-ray spectroscopy (EDS or EDX), X-ray diffraction (XRD), and inductively coupled plasma spectroscopy (ICP) can also be used to detect and identify the elemental types and chemical composition of the positive electrode active material and the coating layer. These methods can also be used to analyze parameters such as the thickness of the coating layer and the content ratio of each component of the coating layer in the coated particulate matter (such as doped / coated modified oxide positive electrode active materials).

[0211] For doped / coated modified oxide-based cathode active materials, particle cross-sections can be obtained by methods such as FIB (Focused Ion Beam) and CP (Ion Beam Cross-Section Polishing). For example, a Hitachi-IM5000 ion beam polisher can be used for cutting. The particle cross-sectional morphology can be observed under HRTEM (High Resolution Transmission Electron Microscopy, such as Thermo Scientific-Talos F200S G2). A clear boundary can be observed at the coating interface. Based on the HRTEM image, parameters such as the average thickness (D1) of the coating layer can be analyzed and calculated. Further, by combining one or more methods such as energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometry (ICP), the types and content parameters of substances in the coating layer and the cathode active material can be identified respectively.

[0212] Solid-state batteries can be disassembled, and the solid materials in the positive electrode active layer can be extracted for particle structure analysis and / or elemental analysis, such as TEM.

[0213] Unless otherwise specified, the "carbon conductive material" and "oxide-type oxygen-absorbing material" in carbon composite oxygen-absorbing materials can be identified by the following methods and instruments: Cut the particles to form a cross-section, observe the particle cross-section under HRTEM (high-resolution transmission electron microscopy), and a clear boundary can be observed at the coating interface, thus distinguishing the bulk positive electrode active body and the coating layer. Then, using the elemental analysis results of energy-dispersive X-ray spectroscopy (EDX), not only can the boundary between the positive electrode active body and the coating layer be distinguished more accurately, but the types and distribution locations of doping elements in the positive electrode active body and the types and distribution locations of elements in the coating layer can also be identified. Therefore, the carbon conductive material and oxygen-absorbing material (including oxide-type oxygen-absorbing material) in the coating layer can be distinguished. Combined with the elemental distribution profile, parameters such as the coating layer thickness at different locations, the distribution area of ​​doping elements relative to the surface of the positive electrode active body, and the size (maximum particle size and / or average particle size) of the carbon conductive material and the size (maximum particle size and / or average particle size) of the oxygen-absorbing material can be measured. For example, the number of statistical locations for statistical analysis of the average thickness of the coating layer can be ≥3, optionally ≥5. For statistical analysis of the maximum particle size of nanoparticles (carbon conductive materials or oxygen-absorbing materials), the number of particles to be counted can be ≥4, optionally ≥8. For statistical analysis of the average particle size of nanoparticles (carbon conductive materials or oxygen-absorbing materials), the number of particles to be counted can be ≥4, optionally ≥8.

[0214] In some embodiments, the doping element includes one or more of cerium, iron, titanium, copper and zirconium, and the oxygen-absorbing material includes one or more of cerium oxide, iron oxide, titanium oxide and yttrium barium copper oxide (YBCO).

[0215] By selecting the aforementioned types of doping elements and oxygen-absorbing materials and incorporating them into the lattice of the positive electrode active body, the appropriate ion size of the doping elements can promote the generation of lithium vacancies and change the electronic structure, thereby enhancing lithium-ion migration kinetics. In addition, by utilizing the variable valence state characteristics of doping elements such as cerium, iron, titanium, copper, and zirconium, electron transfer can occur within the lattice, potentially generating oxygen vacancies and suppressing electron localization. These doping elements can better regulate the electronic structure of the positive electrode active body and better stabilize the lattice of the positive electrode active body. These oxygen-absorbing materials, while possessing good oxygen absorption capacity, also have better high-voltage resistance, and can more stably exert their oxygen absorption effect. This is beneficial for better improving the structural stability and ion conduction stability of sulfide solid electrolytes, better promoting the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0216] In this application, unless otherwise specified, the oxygen vacancy index of some exemplary oxide-type oxygen-absorbing substances may be defined as follows:

[0217] The chemical representation of cerium oxide is CeO. 2-δ1δ1 can be defined as the oxygen vacancy index of the corresponding cerium oxide.

[0218] Iron oxides can be chemically represented as Fe2O 3-δ2 δ2 can be defined as the oxygen vacancy index of the corresponding iron oxide.

[0219] The chemical representation of titanium oxide is TiO. 2-δ3 δ3 can be defined as the oxygen vacancy index of the corresponding titanium oxide.

[0220] The chemical representation of yttrium barium copper oxide is YBa₂Cu₃O. 7-δ4 δ4 can be defined as the oxygen vacancy index of the corresponding yttrium barium copper oxide.

[0221] In this application, unless otherwise specified, the "oxygen vacancy index" is used to measure the quantity of oxygen vacancies. A higher oxygen vacancy index indicates a greater number of oxygen vacancies. The corresponding oxygen vacancy index can be determined based on the chemical formula of the oxygen-absorbing substance. Furthermore, the oxygen vacancy index can be measured using instruments and methods conventional in the art, including but not limited to X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), Raman spectroscopy, and electron paramagnetic resonance spectroscopy (EPR). In addition, the oxygen vacancy index can be controlled using methods already existing in the art, such as high-temperature oxidation or reduction treatments.

[0222] Without limitation, the mass percentage of oxide-type oxygen absorber relative to the oxygen absorber in the carbon composite oxygen absorber (which can be denoted as F) O1 The percentage can be 80% to 100%, or optionally 90% to 100%, or any of the following percentages or a range consisting of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 99%, 100%, etc.

[0223] In some embodiments, the oxygen-absorbing material includes cerium oxide (CeO). 2-δ1 Non-limiting, cerium oxide (CeO) 2-δ1 The oxygen vacancy index δ1 can be 0 to 0.5, can be selected from 0 to 0.35, or can be any of the following values ​​or a range composed of any two of the following values: 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0224] In some embodiments, the oxygen-absorbing substance includes iron oxide (Fe2O). 3-δ2 Non-limitingly, iron oxide Fe2O3-δ2 The oxygen vacancy index δ2 can be 0 to 0.7, can be selected from 0 to 0.2, or can be any of the following values ​​or a range composed of any two of the following values: 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, etc.

[0225] In some embodiments, the oxygen-absorbing material includes titanium oxide (TiO2). 2-δ3 Non-limiting, titanium oxide (TiO2) 2-δ3 The oxygen vacancy index δ3 can be 0 to 0.25, can be selected from 0 to 0.2, or can be any of the following values ​​or a range composed of any two of the following values: 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.25, etc.

[0226] In some embodiments, the oxygen-absorbing substance includes yttrium barium copper oxide (YBa₂Cu₃O). 7-δ4 Non-limiting, yttrium barium copper oxide YBa₂Cu₃O 7-δ4 The oxygen vacancy index δ4 is 0 to 0.5, and can be selected from 0 to 0.1. It can also be any of the following values ​​or a range composed of any two of the following values: 0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.14, 0.15, 0.16, 0.18, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc.

[0227] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0228] (a1) The mass percentage of oxide-type oxygen-absorbing material relative to the oxygen-absorbing material in carbon composite oxygen-absorbing material is 80% to 100%;

[0229] (a2) Oxygen-absorbing substances include cerium oxide (CeO). 2-δ1 cerium oxide CeO 2-δ1 The oxygen vacancy index δ1 is 0–0.5;

[0230] (a3) Oxygen-absorbing substances include iron oxide (Fe2O) 3-δ2 Iron oxide Fe2O 3-δ2The oxygen vacancy index δ2 is 0–0.7;

[0231] (a4) Oxygen-absorbing substances include titanium oxide (TiO2). 2-δ3 Titanium oxide (TiO) 2-δ3 The oxygen vacancy index δ3 ranges from 0 to 0.25.

[0232] (a5) Oxygen-absorbing substances include yttrium barium copper oxide (YBa2Cu3O). 7-δ4 Yttrium barium copper oxide YBa2Cu3O 7-δ4 The oxygen vacancy index δ4 is 0 to 0.5.

[0233] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0234] (a1') The mass percentage of oxide-type oxygen absorbers relative to the oxygen absorbers in carbon composite oxygen absorbers is 90% to 100%;

[0235] (a2') Oxygen-absorbing substances include cerium oxide (CeO). 2-δ1 cerium oxide CeO 2-δ1 The oxygen vacancy index δ1 ranges from 0 to 0.35.

[0236] (a3') Oxygen-absorbing substances include iron oxide (Fe2O) 3-δ2 Iron oxide Fe2O 3-δ2 The oxygen vacancy index δ2 is 0–0.2;

[0237] (a4') Oxygen-absorbing substances include titanium oxide (TiO2). 2-δ3 Titanium oxide (TiO) 2-δ3 The oxygen vacancy index δ3 is 0–0.2;

[0238] (a5') Oxygen-absorbing substances include yttrium barium copper oxide (YBa2Cu3O). 7-δ4 Yttrium barium copper oxide YBa2Cu3O 7-δ4 The oxygen vacancy index δ4 is 0 to 0.1.

[0239] By controlling the mass ratio of oxide-type oxygen absorbers to oxygen absorbers in carbon composite oxygen absorbers (F... O1 Within the aforementioned range, the better stability of oxide-type oxygen-absorbing materials at high oxidation potentials of the positive electrode can better leverage the oxygen absorption effect of carbon composite oxygen-absorbing materials, which is more conducive to improving the structural stability of sulfide solid electrolytes, and more conducive to promoting the capacity utilization of the positive electrode and significantly improving the cycle performance of solid-state batteries.

[0240] By controlling the oxygen-absorbing substances to be the aforementioned types, it is beneficial to provide better oxygen absorption.

[0241] In some embodiments, at least one of the doping element and the oxide-type oxygen-absorbing material includes cerium.

[0242] In some implementations, the doping element includes cerium. That is, the doping element includes cerium dopant.

[0243] In some embodiments, the oxygen-absorbing material includes cerium oxide. Non-limitingly, the mass percentage of cerium oxide relative to the oxygen-absorbing material in the carbon composite oxygen-absorbing material can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 99%, 100%, etc.

[0244] Cerium doping can better control the electronic structure of the positive electrode active body; in addition, based on the radius size characteristics of cerium ions, after cerium element is doped into the lattice of the positive electrode active body, it can form strong chemical bonds with the surrounding oxygen, such as Ce-O bonds, which can enhance the binding force of the lattice to oxygen, improve lattice stability, suppress oxygen release, and significantly improve the cycle performance of solid-state batteries.

[0245] Cerium oxide has good oxygen adsorption properties, providing abundant oxygen vacancies. It also has good high voltage resistance, which can provide better oxygen absorption and significantly improve the cycle performance of solid-state batteries.

[0246] In some implementations, the doping element includes cerium, and the oxygen-absorbing material includes cerium oxide.

[0247] Controlling the cerium dopant element in the positive electrode active body to be the same cerium element present in the cerium oxide in the coating layer is beneficial to more uniformly disperse the internal stress generated by the lattice during charging and discharging, which is more conducive to further improving the structural stability of oxide-based positive electrode active materials and further suppressing oxygen release; thus, the cycle performance of solid-state batteries can be significantly improved.

[0248] In some embodiments, cerium oxide includes cerium oxide (CeO2).

[0249] Compared to other types of cerium oxides, cerium oxide has higher pressure resistance, better stability, and is simpler to prepare.

[0250] In some embodiments, the doping element and the oxide-type oxygen absorber include at least one of the same elements.

[0251] In some embodiments, the carbon composite oxygen-absorbing material is a composite material based on a carbon conductive material and an oxygen-absorbing material, wherein the oxygen-absorbing material includes an oxide-type oxygen-absorbing material, and the doping element and the oxide-type oxygen-absorbing material include at least one of the same elements.

[0252] In some embodiments, the carbon composite oxygen absorber is a composite material based on carbon conductive material and oxide-type oxygen absorber, wherein the doping element and the oxide-type oxygen absorber include at least one of the same elements.

[0253] By controlling the doping elements in the positive electrode active body to include at least one of the same elements as the carbon composite oxygen-absorbing material, the bulk phase and coating layer of the positive electrode active body contain the same type of elements. This is beneficial for more uniformly dispersing the internal stress generated by the lattice during charging and discharging, further improving the structural stability of oxide-based positive electrode active materials, suppressing oxygen release, further improving the structural stability and ion-conducting effect of sulfide solid electrolytes, better improving the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0254] In some implementations, the mass percentage (F) of the dopant element in the positive electrode active body X0 The percentage can be 0.1% to 5%, or 0.1% to 2%, or any of the following percentages or a range consisting of any two of the following percentages: 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0255] In some embodiments, at least a portion of the dopant elements are located on the surface of the positive electrode active body. Non-limitingly, the dopant elements in the positive electrode active body may be located in a portion 0-50 nm from the outer surface of the positive electrode active body; optionally, the dopant elements in the positive electrode active body may be located in a portion 0-5 nm from the outer surface of the positive electrode active body. Non-limitingly, the distance of the distribution position of the dopant elements in the positive electrode active body relative to the outer surface of the positive electrode active body may be greater than or equal to 0 and less than or equal to any of the following values: 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.

[0256] In some embodiments, the dopant element includes cerium. Non-limitingly, the mass percentage of the cerium dopant element in the positive electrode active body can be 0.1% to 5%, optionally 0.1% to 2%, or any of the following percentages or a range selected from any two of the following percentages: 0.1%, 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0257] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0258] (b1) Mass percentage of dopant elements in the positive electrode active bulk (F) X0 The percentage is 0.1% to 5%.

[0259] (b2) At least a portion of the dopant elements are located on the surface of the positive electrode active body; optionally, the dopant elements in the positive electrode active body are located at a distance of 0 to 50 nm from the outer surface of the positive electrode active body.

[0260] (b3) The doping element includes cerium, and the mass percentage of cerium doping element in the positive electrode active body is 0.1% to 5%.

[0261] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0262] (b1') The mass percentage of doped elements in the positive electrode active body is 0.1% to 2%;

[0263] (b2') The doping elements in the positive electrode active body are located in the portion 0-5 nm away from the outer surface of the positive electrode active body;

[0264] (b3') The doping element includes cerium, and the mass percentage of cerium doping element in the positive electrode active body is 0.1% to 2%.

[0265] When at least some of the doping elements are located on the surface of the positive electrode active body, the electronic structure of the positive electrode active body surface can be better regulated, and surface oxygen release can be suppressed. Moreover, the doping elements located on the surface of the positive electrode active body can have a better synergistic effect with the same elements in the carbon composite oxygen-absorbing material of the coating layer, and better disperse internal stress. Thus, the cycle performance of solid-state batteries can be significantly improved.

[0266] In some embodiments, in the carbon composite oxygen-absorbing material, the mass percentage (R) of the carbon conductive material relative to the oxygen-absorbing material is... 10 The percentage can be 0.5% to 5%, or optionally 0.5% to 2.5%, or any of the following percentages or a range consisting of any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0267] In some embodiments, the mass percentage (R) of the carbon conductive material relative to the oxygen-absorbing material in the coating layer is... 11 The percentage can be 0.5% to 5%, or optionally 0.5% to 2.5%, or any of the following percentages or a range consisting of any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0268] In some embodiments, the mass percentage (F) of the carbon composite oxygen-absorbing material in the coating layer 21 The percentage can be 80% to 100%, or optionally 90% to 100%, or any of the following percentages or a range consisting of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 99%, 100%, etc.

[0269] In some embodiments, the sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the coating layer (F) 22 The percentage can be 80% to 100%, or 90% to 100%, or any of the following percentages or a range of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 99%, 100%, etc.

[0270] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0271] (c1) In carbon composite oxygen-absorbing materials, the mass percentage of carbon conductive material relative to oxygen-absorbing material is 0.5% to 5%;

[0272] (c2) In the coating layer, the mass percentage of carbon conductive material relative to oxygen-absorbing material is 0.5% to 5%;

[0273] (c3) The mass percentage of carbon composite oxygen-absorbing material in the coating layer is 80% to 100%;

[0274] (c4) The sum of the mass percentages of carbon conductive material and oxygen-absorbing material in the coating layer is 80% to 100%.

[0275] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0276] (c1') In carbon composite oxygen-absorbing materials, the mass percentage of carbon conductive material relative to oxygen-absorbing material is 0.5% to 2.5%;

[0277] (c2') In the coating layer, the mass percentage of carbon conductive material relative to oxygen-absorbing material is 0.5% to 2.5%;

[0278] (c3') The mass percentage of carbon composite oxygen-absorbing material in the coating layer is 80% to 100%;

[0279] (c4') The sum of the mass percentages of carbon conductive material and oxygen-absorbing material in the coating layer is 80% to 100%.

[0280] By controlling the mass percentage of carbon conductive material relative to oxygen-absorbing material in the carbon composite oxygen-absorbing material and / or coating layer (corresponding to R in the carbon composite oxygen-absorbing material) 10 R in the coating layer 11 This approach helps to better balance the oxygen absorption capacity of oxygen-absorbing materials, the electron transport capacity of carbon conductive materials, and the synergistic effect of doping elements and the same elements in oxide-type oxygen-absorbing materials. It also helps to better improve the structural stability of positive electrode active materials, the structural stability of sulfide solid electrolytes, the overall conductivity of the coating layer, the contact stability and chemical stability of the positive electrode interface, and thus better promote the utilization of positive electrode capacity and significantly improve the cycle performance of solid-state batteries.

[0281] By adjusting the mass percentage (F) of the carbon composite oxygen-absorbing material in the coating layer 21 The sum of the mass percentages of carbon conductive material and oxygen-absorbing material in the coating layer (F) 22 If one or two of the parameters are within the aforementioned range, it is beneficial to control the coating amount within a more suitable range, thereby better promoting the positive electrode capacity and significantly improving the cycle performance of solid-state batteries.

[0282] In some embodiments, the mass percentage (F) of the carbon composite oxygen-absorbing material in the doped / coated modified oxide-based cathode active material is... 20The percentage can be 0.5% to 5%, or can be 1.5% to 5% or 0.5% to 3%. It can also be any of the following percentages or a range consisting of any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0283] In some embodiments, the mass percentage (F) of the coating layer in the doped / coated modified oxide-based cathode active material is... 10 The percentage can be 0.5% to 5%, or can be 1.5% to 5% or 0.5% to 3%. It can also be any of the following percentages or a range consisting of any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0284] In some embodiments, the carbon composite oxygen-absorbing material includes carbon composite cerium oxide, wherein the mass percentage of carbon composite cerium oxide in the doped / coated modified oxide-based positive electrode active material can be 0.5% to 5%, optionally 1.5% to 5% or 0.5% to 3%, or can be any of the following percentages or a range selected from any two of the following percentages: 0.5%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0285] In some embodiments, the average thickness (D1) of the coating layer can be 5nm to 60nm, optionally 15nm to 40nm, further optionally 20nm to 40nm, or 20nm to 60nm, or any of the following values ​​or a range selected from any two of the following values: 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 55nm, 60nm, etc.

[0286] In some embodiments, the thickness of at least a portion of the coating layer can be 5nm to 60nm, optionally 15nm to 40nm, further optionally 20nm to 40nm, or 20nm to 60nm, or any of the following values ​​or a range selected from any two of the following values: 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 55nm, 60nm, etc.

[0287] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0288] (d1) The mass percentage of carbon composite oxygen-absorbing material in doped / coated modified oxide cathode active materials is 0.5% to 5%;

[0289] (d2) The mass percentage of the coating layer in the doped / coated modified oxide cathode active material is 0.5% to 5%;

[0290] (d3) Carbon composite oxygen-absorbing materials include carbon composite cerium oxide, and the mass percentage of carbon composite cerium oxide in doped / coated modified oxide cathode active materials is 0.5% to 5%;

[0291] (d4) The average thickness of the coating layer is 5 nm to 60 nm;

[0292] (d5) At least a portion of the coating layer has a thickness of 5 nm to 60 nm.

[0293] In some embodiments, the doped / coated modified oxide-based cathode active material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0294] (d1') The mass percentage of carbon composite oxygen-absorbing material in doped / coated modified oxide cathode active materials is 1.5% to 5% or 0.5% to 3%;

[0295] The (d2') coating layer accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material;

[0296] (d3') Carbon composite oxygen-absorbing materials include carbon composite cerium oxide, wherein the mass percentage of carbon composite cerium oxide in doped / coated modified oxide cathode active materials is 1.5% to 5% or 0.5% to 3%;

[0297] The average thickness of the (d4') coating layer is 15nm to 40nm, and can be selected as 20nm to 40nm;

[0298] (d5') ​​At least a portion of the coating layer has a thickness of 15nm to 40nm, and may be 20nm to 40nm.

[0299] By adjusting the mass ratio (F) of carbon composite oxygen-absorbing material in doped / coated modified oxide-based positive electrode active materials 20 ), the mass percentage of the coating layer in doped / coated modified oxide cathode active materials (F)10 One or more parameters, such as the average thickness (D1) of the coating layer, are beneficial for controlling the coating amount within a more suitable range. This allows for a better balance between the oxygen absorption capacity of the oxygen-absorbing material, the role of the carbon conductive material in improving the electron transport rate, the synergistic effect of the dopant element and the same element in the oxide-type oxygen-absorbing material, and the ion transport between the positive electrode active material and the positive electrode electrolyte material. This is beneficial for comprehensively improving the structural stability of the positive electrode active material, the structural stability of the sulfide solid electrolyte, the interfacial impedance caused by the coating layer, the contact stability and chemical stability of the positive electrode interface, and thus better promoting the utilization of the positive electrode capacity and significantly improving the cycle performance of the solid-state battery.

[0300] In a non-limiting sense, carbon conductive materials may include one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black, and fullerene.

[0301] In some embodiments, the carbon conductive material is in the form of nanoparticles. Non-limitingly, the average particle size of the carbon conductive material can be 5 nm to 0.21 μm, optionally 5 nm to 0.1 μm, further optionally 30 nm to 0.1 μm, and even more preferably 50 nm to 0.1 μm. It can also be any of the following values ​​or a range selected from any two of the following values: 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 25 nm, 26 nm, 28 nm, 30 nm, 32 nm, 34 nm, 35 nm, 36 nm, 38 nm. The average particle size of carbon conductive materials can also be selected from any of the following ranges: 10nm–0.2μm, 40nm, 45nm, 50nm, 55nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 140nm, 150nm, 160nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.12μm, 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.21μm, etc.

[0302] In some embodiments, the maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, optionally 1 nm to 0.5 μm, further optionally 5 nm to 0.5 μm, even further optionally 8 nm to 0.5 μm, even further optionally 10 nm to 0.5 μm, even further optionally 30 nm to 0.3 μm, even further optionally 50 nm to 0.3 μm, and may also be any of the following values ​​or a range selected from any two of the following values: 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 25 nm, 26 nm, 28 nm, 30 nm, 32 nm. 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 55nm, 60nm, 70nm, 80nm, 90nm, 100nm, 120nm, 140nm, 150nm, 160nm, 180nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 700nm, 800nm, 900nm, 0.1μm, 0.12μm, 0.14μm, 0.15μm, 0.16μm, 0.18μm, 0.2μm, 0.25μm, 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, etc. The maximum particle size of carbon conductive materials can also be selected from any of the following ranges: 20nm~0.5μm, 50nm~0.5μm, 5nm~50nm, 8nm~200nm, 300nm~0.5μm, 10nm~0.3μm, 10nm~0.2μm, etc.

[0303] In some implementations, the oxygen-absorbing material is nanoparticles.

[0304] Non-limitingly, the average particle size of the oxygen-absorbing substance can be 8nm to 50nm, optionally 10nm to 50nm, optionally 10nm to 20nm, or any of the following values ​​or a range consisting of any two of the following values: 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, etc.

[0305] Non-limitingly, the maximum particle size of the oxygen-absorbing substance may be less than or equal to 200 nm, optionally 1 nm to 200 nm, further optionally 5 nm to 200 nm, even further optionally 10 nm to 200 nm, even further optionally 30 nm to 200 nm, even further optionally 30 nm to 100 nm, or less than or equal to 100 nm, optionally 1 nm to 100 nm, further optionally 5 nm to 100 nm, even further optionally 10 nm to 100 nm, even further optionally 10 nm to 50 nm, or any of the following values, or less than or equal to any of the following values, or selected from any two of the following values. The range of values ​​includes: 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc. The maximum particle size of the oxygen-absorbing material can also be selected from any of the following ranges: 5nm–50nm, 10nm–60nm, 30nm–200nm, 5nm–70nm, 5nm–80nm, etc.

[0306] Non-limitingly, in the oxygen-absorbing material, the maximum particle size of 80% of the quantity can be less than or equal to 200 nm, optionally 1 nm to 200 nm, further optionally 5 nm to 200 nm, even further optionally 10 nm to 200 nm, even further optionally 30 nm to 200 nm, even further optionally 30 nm to 100 nm, or less than or equal to 100 nm, optionally 1 nm to 100 nm, further optionally 5 nm to 100 nm, even further optionally 10 nm to 100 nm, even further optionally 10 nm to 50 nm, or can be any of the following values, or less than or equal to any of the following values, or selected from any of the following The ranges comprised of two numerical values ​​are: 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, and 200nm. In oxygen-absorbing materials, the maximum particle size for 80% of the total quantity can also be selected from any of the following ranges: 5nm–50nm, 10nm–60nm, 30nm–200nm, 5nm–70nm, and 5nm–80nm.

[0307] In some implementations, the oxygen-absorbing material includes nano-cerium oxide.

[0308] Non-limitingly, the average particle size of the nano-cerium oxide can be 8nm to 50nm, optionally 10nm to 50nm, optionally 10nm to 20nm, or any of the following values ​​or a range consisting of any two of the following values: 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, etc.

[0309] Non-limitingly, the maximum particle size of the nano-cerium oxide can be less than or equal to 200 nm, optionally 1 nm to 200 nm, further optionally 5 nm to 200 nm, even more preferably 10 nm to 200 nm, even more preferably 30 nm to 200 nm, even more preferably 30 nm to 100 nm, or less than or equal to 100 nm, optionally 1 nm to 100 nm, further preferably 5 nm to 100 nm, even more preferably 10 nm to 100 nm, even more preferably 10 nm to 50 nm, or any of the following values, or less than or equal to any of the following values, or selected from any two of the following. The range of numerical values ​​includes: 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc. The maximum particle size of nano-cerium oxide can also be selected from any of the following ranges: 5nm~50nm, 10nm~60nm, 20nm~200nm, 25nm~200nm, 30nm~200nm, 5nm~70nm, 5nm~80nm, etc.

[0310] Non-limitingly, in the cerium oxide nanoparticles, the maximum particle size of 80% of the particles can be less than or equal to 200 nm, optionally 1 nm to 200 nm, further optionally 5 nm to 200 nm, even more preferably 10 nm to 200 nm, even more preferably 30 nm to 200 nm, even more preferably 30 nm to 100 nm, or less than or equal to 100 nm, optionally 1 nm to 100 nm, further preferably 5 nm to 100 nm, even more preferably 10 nm to 100 nm, even more preferably 10 nm to 50 nm, or can be any of the following values, or less than or equal to any of the following values, or selected from the following The range of any two numerical values ​​is: 1nm, 2nm, 3nm, 4nm, 5nm, 6nm, 8nm, 10nm, 12nm, 14nm, 15nm, 16nm, 18nm, 20nm, 22nm, 24nm, 25nm, 26nm, 28nm, 30nm, 32nm, 34nm, 35nm, 36nm, 38nm, 40nm, 45nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, etc. In nano-cerium oxide, the maximum particle size of 80% of the samples can also be selected from any of the following ranges: 5nm–50nm, 10nm–60nm, 30nm–200nm, 5nm–70nm, 5nm–80nm, etc.

[0311] In some embodiments, the carbon composite oxygen-absorbing material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0312] (e1) Carbon conductive materials include one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene.

[0313] (e2) The carbon conductive material is a nanoparticle. Optionally, the average particle size of the carbon conductive material is 5 nm to 0.21 μm. The average particle size refers to the average of the maximum particle size of each particle. The maximum particle size refers to the maximum diameter among the diameters of the particles in all directions.

[0314] (e3) The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected from 1 nm to 0.5 μm, and further selected from 5 nm to 0.5 μm;

[0315] (e4) The oxygen-absorbing material is nanoparticles, and optionally, the average particle size of the oxygen-absorbing material is 8 nm to 50 nm.

[0316] (e5) The maximum particle size of the oxygen-absorbing substance is less than or equal to 200 nm, and can be selected from 1 nm to 200 nm;

[0317] (e6) Oxygen-absorbing substances include nano-cerium oxide, with an average particle size of 10 nm to 50 nm.

[0318] (e7) The oxygen-absorbing material includes nano-cerium oxide, the maximum particle size of which is less than or equal to 200 nm, and can be selected from 1 nm to 200 nm.

[0319] In some embodiments, the carbon composite oxygen-absorbing material satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0320] (e1') Carbon conductive materials include vapor-grown carbon fibers;

[0321] The average particle size of (e2') carbon conductive materials is 30 nm to 0.1 μm;

[0322] (e3') The maximum particle size of the carbon conductive material is 8 nm to 0.5 μm, which can be selected as 10 nm to 0.3 μm, and further can be selected as 50 nm to 0.3 μm;

[0323] (e4') The average particle size of the oxygen-absorbing substance is 10 nm to 20 nm;

[0324] (e5') The maximum particle size of oxygen-absorbing substances is 5nm to 100nm;

[0325] (e6') Oxygen-absorbing materials include nano-cerium oxide, with an average particle size of 10nm to 20nm;

[0326] (e7') Oxygen-absorbing materials include nano-cerium oxide, with a maximum particle size of 5nm to 100nm.

[0327] In this application, the "maximum particle size" of a certain particle refers to the largest diameter among its anisotropic diameters. For powder materials composed of multiple particles, the size and size distribution of the material particles can be controlled by controlling the distribution range of the "maximum particle size". Taking carbon conductive materials as an example, "the maximum particle size of the carbon conductive material is A1 to A2" means that the distribution range of the maximum particle size of the carbon conductive material is within the range of A1 to A2.

[0328] In this application, the "average particle size" of multiple particles refers to the average of the maximum diameter of each particle, that is, the average of the maximum particle size of each particle.

[0329] By controlling one or more parameters of the size (average particle size and / or maximum particle size) of the carbon conductive material and the size (average particle size and / or maximum particle size) of the oxygen-absorbing material within the aforementioned smaller nanoscale range, the aggregation and adsorption characteristics of small-sized nanoparticles can be utilized to improve the bonding stability between the carbon conductive material and the oxygen-absorbing material in the carbon composite oxygen-absorbing material, as well as the bonding stability between the coating layer and the positive electrode active body. This is beneficial for improving the structural stability of the positive electrode active material, and also for more stably performing the function of isolating the direct contact of the sulfide solid electrolyte and inhibiting oxygen release, promoting a more stable performance of the positive electrode capacity, and significantly improving the cycle performance of solid-state batteries.

[0330] In some embodiments, the doped oxide-type positive electrode active material has a layered crystal structure.

[0331] For oxide-based cathode active materials with layered crystal structures, the introduction of doped / coated modified oxide-based cathode active materials has a significant effect on improving the structural stability of the cathode active materials and inhibiting oxygen release.

[0332] Doped / coated modified oxide cathode active materials include at least a cathode active body. The "cathode active body" is the fundamental part of the doped / coated modified oxide cathode active material that has the ability to reversibly extract and insert active ions.

[0333] In some embodiments, the positive electrode active material includes a lithium transition metal oxide. Further, the doped oxide-type positive electrode active material is at least a portion of the lithium transition metal oxide, that is, the doped oxide-type positive electrode active material belongs to the lithium transition metal oxide category.

[0334] In this application, unless otherwise specified, "lithium transition metal oxide" refers to a positive electrode active material containing lithium, transition metal, and oxygen. It is understood that lithium transition metal oxides have the ability to reversibly extract and insert active ions. Therefore, lithium transition metal oxides include non-lithium metal elements, and non-lithium metal elements include transition metal elements. Non-limitingly, in lithium transition metal oxides, the molar percentage of transition metal elements relative to non-lithium metal elements can be 90% to 100%, and can also be any of the following percentages or a range selected from any two of the following percentages: 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, etc.

[0335] In this application, unless otherwise specified, "non-lithium metal element" refers to a metal element that is different from lithium (Li).

[0336] In some embodiments, the positive electrode active body comprises a lithium transition metal oxide, and the doped oxide-type positive electrode active material is at least a portion of the lithium transition metal oxide; the positive electrode active body satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0337] (f1) Lithium transition metal oxides include lithium nickel-based oxides, which include Li, non-lithium metal elements and O, and non-lithium metal elements include Ni.

[0338] (f2) Lithium transition metal oxides have a layered crystal structure;

[0339] (f3) The mass percentage of lithium transition metal oxides in the positive electrode active body is 95% to 100%.

[0340] By incorporating lithium transition metal oxides (such as lithium nickel-based oxides), it is beneficial to improve the energy density of solid-state batteries.

[0341] In some embodiments, the lithium transition metal oxide has a layered crystal structure.

[0342] In some embodiments, the lithium transition metal oxide includes lithium nickel-based oxides. In this application, unless otherwise specified, "lithium nickel-based oxide" refers to a lithium transition metal oxide comprising lithium, nickel, and oxygen. In this case, the non-lithium metal element in the lithium transition metal oxide includes nickel (Ni). Without limitation, the lithium nickel-based oxide may include one or more of lithium nickel cobalt manganese-based oxides and lithium nickel cobalt aluminum-based oxides.

[0343] In this application, unless otherwise specified, "lithium nickel cobalt manganese-based oxide" refers to a lithium transition metal oxide comprising lithium, nickel, cobalt, manganese, and oxygen, and more specifically, a lithium nickel-based oxide. It is understood that lithium nickel cobalt manganese-based oxide includes lithium (Li), non-lithium metal elements, and oxygen (O), wherein the non-lithium metal elements include nickel (Ni), cobalt (Co), and manganese (Mn). In this application, unless otherwise specified, lithium nickel cobalt manganese-based oxides used as positive electrode active materials typically have a layered structure.

[0344] In this application, unless otherwise specified, “lithium nickel cobalt aluminum-based oxide” refers to lithium transition metal oxides that include lithium (Li), nickel (Ni), cobalt (Co), aluminum (Al) and oxygen (O).

[0345] In some embodiments, the lithium nickel-based oxide has a layered crystal structure.

[0346] In this application, the atomic molar ratio of Ni to non-lithium metal elements in lithium nickel-based oxides is denoted as q1; the atomic molar ratio of Ni to Li in lithium nickel-based oxides is denoted as q2:x2; and the atomic molar ratio of Ni to O in lithium nickel-based oxides is denoted as q3:x3. When the lithium nickel-based oxide contains Co, the atomic molar ratio of Co to non-lithium metal elements in the lithium nickel-based oxide is denoted as q4. When the lithium nickel-based oxide contains Mn, the atomic molar ratio of Mn to non-lithium metal elements in the lithium nickel-based oxide is denoted as q5.

[0347] Without limitation, q1, q2 and q3 can each be any of the following values, or a range of any two of the following values: 0.8, 0.81, 0.82, 0.84, 0.85, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, etc.

[0348] Without limitation, x2 can be any of the following values, or a range consisting of any two of the following values: 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.05, 1.1, 1.15, 1.2, etc.

[0349] Without limitation, x3 can be any of the following values, or a range consisting of any two of the following values: 1.6, 1.7, 1.8, 1.9, 2, 2.05, 2.06, 2.08, 2.1, 2.2, etc.

[0350] Without limitation, q4 can be any of the following values, or a range consisting of any two of the following values: 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.14, 0.15, etc.

[0351] Without limitation, q5 can be any of the following values, or a range selected from any two of the following values: 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.14, 0.15, etc.

[0352] In some embodiments, the lithium transition metal oxide includes lithium nickel-based oxide;

[0353] The positive electrode active body satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0354] (i1) The atomic molar ratio of Ni to non-lithium metal elements in lithium nickel-based oxides is q1, where 0.8 ≤ q1 ≤ 0.95;

[0355] (i2) The lithium nickel-based oxide contains Ni and Li elements in an atomic molar ratio of q2:x2, wherein 0.8≤q2≤0.95 and 0.6≤x2≤1.2;

[0356] (i3) The lithium nickel-based oxide contains Ni and O elements in an atomic molar ratio of q3:x3, wherein 0.8≤q3≤0.95 and 1.6≤x3≤2.2;

[0357] (i4) The lithium nickel-based oxide contains the element Co, and the atomic molar ratio of the element Co to the non-lithium metal element in the lithium nickel-based oxide is q4, wherein 0.02≤q4≤0.15, and optionally 0.05≤q4≤0.15;

[0358] (i5) The lithium nickel-based oxide contains the element Mn, and the atomic molar ratio of the element Mn to the non-lithium metal element in the lithium nickel-based oxide is q5, wherein 0.02≤q5≤0.15, and optionally 0.05≤q5≤0.15;

[0359] (i6) Lithium nickel-based oxides have a layered crystal structure;

[0360] (i7) The mass percentage of lithium nickel-based oxides in lithium transition metal oxides is 80% to 100%;

[0361] (i8) The mass percentage of lithium nickel-based oxides in the positive electrode active body is 80% to 100%.

[0362] In some implementations, the positive electrode active body satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0363] (j1)0.81≤q1≤0.93;

[0364] (j2)0.81≤q2≤0.93;

[0365] (j3)0.8≤x2≤1.1;

[0366] (j4)0.81≤q3≤0.93;

[0367] (j5)1.8≤x3≤2.06;

[0368] (j6) Lithium nickel-based oxides contain Co, 0.08≤q4≤0.1;

[0369] (j7) Lithium nickel-based oxides contain Mn element, 0.08≤q5≤0.1;

[0370] (j8) The mass percentage of lithium nickel-based oxides in lithium transition metal oxides is 90% to 100%;

[0371] (j9) The mass percentage of lithium nickel-based oxide in the positive electrode active body is 90% to 100%;

[0372] (j10) Lithium transition metal oxides include lithium nickel cobalt manganese-based oxides; optionally, in lithium nickel cobalt manganese-based oxides, the ratio of the sum of the atomic molar ratios of nickel, cobalt, and manganese to the sum of the atomic molar ratios of non-lithium metal elements is denoted as R. NCM R NCM The value is 0.9 to 1; further optionally, R NCM It ranges from 0.96 to 1.

[0373] For the aforementioned types of lithium transition metal oxides (such as lithium nickel-based oxides with high nickel content), the introduction of doped / coated modified oxide cathode active materials has a significant effect on improving the structural stability of the cathode active material and suppressing oxygen release.

[0374] Non-limitingly, the mass percentage of lithium nickel-based oxide in lithium transition metal oxide can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0375] Non-limitingly, the mass percentage of lithium nickel-based oxide in the positive electrode active body can be 80% to 100%, optionally 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0376] In some embodiments, the lithium transition metal oxide includes lithium nickel cobalt manganese-based oxides.

[0377] In lithium nickel cobalt manganese-based oxides, the ratio of the sum of the atomic molar ratios of nickel, cobalt, and manganese to the sum of the atomic molar ratios of non-lithium metal elements is denoted as R. NCM In a non-restrictive sense, R NCM It can be 0.9 to 1, can be selected from 0.96 to 1, or can be any of the following values, or selected from a range consisting of any two of the following values: 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, 1, etc.

[0378] In lithium nickel cobalt manganese-based oxides, the ratio of the atomic molar ratio of nickel to the sum of the atomic molar ratios of nickel, cobalt, and manganese is denoted as R. Ni The ratio of the atomic molar ratio of cobalt to the sum of the atomic molar ratios of nickel, cobalt, and manganese is denoted as R. Co The ratio of the atomic molar ratio of manganese to the sum of the atomic molar ratios of nickel, cobalt, and manganese is denoted as R. Mn .

[0379] Without limitation, R Ni It can be any of the following values, or a range selected from any two of the following values: 0.8, 0.81, 0.82, 0.84,

[0380] 0.85, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, etc. R Ni You can also refer to the values ​​or range of q1.

[0381] Without limitation, R Co It can be any of the following values, or a range selected from any two of the following values: 0.02, 0.03, 0.04,

[0382] 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.14, 0.15, etc. R Co You can also refer to the values ​​or range of q4.

[0383] Without limitation, R Mn It can be any of the following values, or a range selected from any two of the following values: 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.12, 0.14, 0.15, etc. R Mn You can also refer to the values ​​or range of q5.

[0384] Non-limitingly, the mass percentage of lithium nickel cobalt manganese-based oxide in lithium transition metal oxide can be 80% to 100%, further optionally 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0385] In some embodiments, the lithium transition metal oxide includes a ternary cathode material, which may be selected as a ternary cathode material. In this application, the "ternary cathode material" is composed of Li, nickel, cobalt, M2, and oxygen; wherein, M2 can be manganese or aluminum. When M2 is manganese (Mn), the ternary cathode material is lithium nickel cobalt manganese oxide, which can be denoted as NCM; when M2 is aluminum (Al), the ternary cathode material is lithium nickel cobalt aluminum oxide, which can be denoted as NCA.

[0386] Those skilled in the art can use one or more elemental analysis methods, including but not limited to energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectrometry (ICP), to perform compositional analysis on the positive electrode active material in the positive electrode layer.

[0387] Taking solid-state batteries with lithium-ion active ions as an example, it is understandable that lithium (Li) is intercalated and deintercalated during the charging and discharging process, and the Li content in the positive electrode layer varies depending on the state of discharge. In the exemplary description of the positive electrode active material in this application, unless otherwise specified, the Li content can be the initial state of the material or a non-initial state after charge-discharge cycles. When the positive electrode active material is applied to the positive electrode layer in a solid-state battery system, the Li content in the positive electrode active material contained in the positive electrode layer usually changes after charge-discharge cycles. The Li content can be measured using atomic molar content, but is not limited to this. Regarding "Li content is the initial state of the material," the initial state of the material refers to the state before the positive electrode layer. It is understood that new materials or substances obtained by appropriate modification based on the listed positive electrode active materials are also within the scope of positive electrode active materials. The aforementioned appropriate modification refers to an acceptable modification method for the positive electrode active material, and non-limiting examples include one or more of coating modification and doping modification. In the exemplary description of the positive electrode active material in this application, the oxygen (O) content is usually a theoretical value. Lattice oxygen release will cause changes in the atomic molar content of oxygen, and the actual O content will fluctuate. The O content can be measured in atomic molar content, but is not limited to this.

[0388] In some embodiments, the sulfide solid electrolyte includes one or more of LGPS-type sulfide electrolytes, binary sulfide electrolytes, and ternary sulfide electrolytes.

[0389] Without limitation, the binary sulfide electrolyte may include one or more of Li2S-GeS2 binary sulfide, Li2S-P2S5 binary sulfide, Li2S-SiS2 binary sulfide, and Li2S-B2S3 binary sulfide.

[0390] Without limitation, ternary sulfide electrolytes may include Argyrodite sulfide electrolytes, Li2S-M... 5 S2-P2S5 ternary sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, Li2S-P2S5-M 6 S-ternary sulfide electrolyte, Li2S-P2S5-M 6 Cl is one or more of a ternary sulfide electrolyte and a thio-LISICON type sulfide electrolyte; M 5 Includes one or more elements selected from silicon (Si), germanium (Ge), tin (Sn), and aluminum (Al); M 6 It includes one or more elements selected from Ge, Al, Sn, lead (Pb), antimony (Sb), Si, and arsenic (As).

[0391] Unless otherwise stated, "LGPS-type sulfide electrolytes" have an LGPS-type crystal phase structure. Non-limiting examples of LGPS-type sulfide electrolytes include Li... 10 GeP2S 12 .

[0392] As an example of a binary sulfide electrolyte, a non-limiting example of a Li2S-P2S5 binary sulfide may include Li7P3S. 11 .

[0393] Unless otherwise specified, the "silver-germanium sulfide" electrolyte has a silver-germanium sulfide crystal phase structure. Non-limiting examples of silver-germanium sulfide electrolytes may include Li6PS5Cl, Li 5.5 PS 5.5 Cl 1.5 Li 5.7 PS5Cl 1.3 wait.

[0394] In some implementations, the positive electrode active layer satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0395] (g1) The mass percentage of doped / coated modified oxide positive electrode active material in the positive electrode active material is 80% to 100%, which can be selected as 90% to 100%, or any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0396] (g2) The mass percentage of doped / coated modified oxide cathode active material in the cathode active layer is 70% to 95%, optionally 75% to 90%, optionally 90% to 100%, and may also be any of the following percentages or a range selected from any two of the following percentages: 70%, 72%, 74%, 75%, 76%, 78%, 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 93%, 94%, 95%, etc.

[0397] (g3) The mass percentage of sulfide solid electrolyte in the positive electrode active layer is 5% to 30%, optionally 10% to 30%, further optionally 10% to 26%, and even further optionally 10% to 25%, and may also be any of the following percentages or a range selected from any two of the following percentages: 5%, 6%, 7%, 8%, 9%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, etc.;

[0398] (g4) The mass percentage of sulfide solid electrolyte in the positive electrode electrolyte material is 80% to 100%, which can be 90% to 100%, or any of the following percentages or a range composed of any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, 96%, 98%, 100%, etc.

[0399] In some implementations, the positive electrode active layer satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0400] (g1') The mass percentage of doped / coated modified oxide cathode active material in cathode active material is 90% to 100%;

[0401] (g2') The mass percentage of doped / coated modified oxide cathode active material in the cathode active layer is 75% to 90%;

[0402] (g3') The mass percentage of sulfide solid electrolyte in the positive electrode active layer is 10% to 30%, preferably 10% to 26%, and further preferably 10% to 25%;

[0403] (g4') The mass percentage of sulfide solid electrolyte in the positive electrode electrolyte material is 90% to 100%.

[0404] Those skilled in the art can identify the types and structures of components in solid-state batteries using one or more of the following detection methods, including but not limited to: Fourier transform infrared (FT-IR) spectroscopy, ultraviolet spectroscopy, and proton nuclear magnetic resonance (NMR) spectroscopy. 1 Methods include 1H NMR, X-ray diffraction (XRD), gel permeation chromatography (GPC), high performance liquid chromatography (HPLC), mass spectrometry, inductively coupled plasma atomic emission spectrometry (ICP), and energy dispersive spectroscopy (EDS). The sample preparation and testing methods for these methods are known to those skilled in the art, and the test parameters can be appropriately adjusted according to the sample characteristics.

[0405] In some implementations, the solid-state battery is an all-solid-state battery;

[0406] In this application, unless otherwise specified, "all-solid-state battery" refers to a solid-state battery in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery, so it can be called "all-solid-state battery".

[0407] In some embodiments, a solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0408] In some implementations, the solid-state battery is a lithium-ion secondary battery; in this case, the active ions include lithium ions.

[0409] In some implementations, the solid-state battery is an all-solid-state lithium-ion secondary battery, which is both an all-solid-state battery and a lithium-ion secondary battery.

[0410] A solid-state battery includes at least one solid-state battery cell. A solid-state battery may include one or more solid-state battery cells.

[0411] In this application, unless otherwise specified, "solid-state battery cell" refers to a basic unit capable of converting chemical energy into electrical energy, and all its components are solid-state. In some embodiments, a solid-state battery cell may be an all-solid-state battery cell.

[0412] In this application, unless otherwise specified, "all-solid-state battery cell" refers to a solid-state battery cell in which all electrolytes are solid electrolytes. In this case, the positive electrode layer, negative electrode layer and electrolyte part are all made of solid materials, and no liquid electrolyte is provided in the battery cell, so it can be called "all-solid-state battery cell".

[0413] Non-limitingly, a solid-state battery cell (which can be an all-solid-state battery cell) may include a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, with the solid electrolyte layer located between the positive and negative electrode layers. During battery charging and discharging, active ions shuttle between the positive and negative electrode layers, inserting and extracting. The solid electrolyte layer serves to conduct ions between the positive and negative electrode layers and also isolates them, thus preventing short circuits between the positive and negative electrodes.

[0414] In some embodiments, the solid-state battery cell 5 includes a solid-state cell 52.

[0415] In some implementations, the solid-state cell is an all-solid-state cell.

[0416] In some embodiments, the solid-state cell 52 (which may be an all-solid-state cell) includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer stacked sequentially.

[0417] The following is a description of the positive electrode layer.

[0418] The positive electrode layer can be formed based on a solid electrolyte membrane or provided by a pre-fabricated positive electrode sheet.

[0419] Unless otherwise stated, the positive electrode layer in this application includes at least a positive electrode active layer.

[0420] Unless otherwise stated in this application, the positive electrode sheet includes at least a positive active layer.

[0421] In this application, unless otherwise specified, the positive electrode active layer includes at least a positive electrode active material, and typically also includes a solid electrolyte material. In this application, unless otherwise specified, the solid electrolyte material in the positive electrode layer may be referred to as "positive electrode electrolyte material". The positive electrode electrolyte material can enhance the ion conductivity of the positive electrode layer, reduce interfacial impedance, and promote the charge transfer efficiency and full release of the capacity of the positive electrode active material with the external environment.

[0422] It is understandable that positive electrode active materials include doped / coated modified oxide positive electrode active materials, and positive electrode electrolyte materials include sulfide solid electrolytes.

[0423] The types of positive electrode active materials in the positive electrode active layer can be referred to in the context of this application. Optionally, it may also include other types of positive electrode active materials known in the art that can be used in the positive electrode layer of solid-state batteries.

[0424] As a non-limiting example, other types of positive electrode active materials may include one or more of the following materials: lithium transition metal oxides, lithium phosphates with an olivine structure, and their respective modifications. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their modifications. Non-limiting examples of lithium cobalt oxides may include LiCoO2; non-limiting examples of lithium nickel oxides may include LiNiO2; non-limiting examples of lithium manganese oxides may include LiMnO2, LiMn2O4, etc.; non-limiting examples of lithium nickel cobalt manganese oxides may include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 Examples of lithium nickel cobalt aluminum oxides include LiNi, etc. 0.80 Co 0.15 Al 0.05 O2. Non-limiting examples of lithium phosphates with an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium iron phosphate include LiFePO4 (also abbreviated as LFP). Examples of lithium manganese phosphate include LiMnPO4.

[0425] In this application, unless otherwise specified, "a modified positive electrode active material" includes the positive electrode active material itself and the modifying element. Furthermore, the modifying element may exist as a dopant element, a coating element, or a combination of a dopant element and a coating element. Unless otherwise specified, "a modified positive electrode active material" still falls within the scope of positive electrode active materials.

[0426] Non-limitingly, the mass percentage of the positive electrode active material in the positive electrode active layer can be ≥70%, or 70% to 95%, or even 75% to 90%, or any of the following percentages or a range selected from any two of the following percentages: 70%, 72%, 74%, 75%, 76%, 78%, 80%, 82%, 84%, 85%, 86%, 88%, 90%, 92%, 94%, 95%, etc.

[0427] The types of solid electrolyte materials in the positive electrode active layer can be found in the context of this application. Optionally, other types of solid electrolyte materials known in the art that can be used in the positive electrode layer of a solid-state battery may also be included.

[0428] Non-limitingly, the mass percentage of the positive electrode electrolyte material in the positive electrode active layer can be 0.1% to 30%, optionally 5% to 30%, further optionally 5% to 25%, also optionally 10% to 30%, further optionally 10% to 26%, even further optionally 10% to 25%, or any of the following percentages or a range selected from any two of the following percentages: 0.1%, 0.5%, 1%, 2%, 4%, 5%, 6%, 7%, 8%, 10%, 12%, 14%, 15%, 16%, 18%, 20%, 22%, 24%, 25%, 26%, 28%, 30%, etc.

[0429] In some embodiments, the positive electrode active layer includes a conductive agent (which may be referred to as a positive electrode conductive agent).

[0430] In some embodiments, the positive electrode active layer optionally includes a conductive agent (which may be referred to as a positive electrode conductive agent). As a non-limiting example, the positive electrode conductive agent may be a carbon conductive agent. Non-limitingly, the carbon conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the positive electrode conductive agent may include, but is not limited to, one or more of SP, KS-6, acetylene black, branched Ketjen black ECP, SFG-6, vapor-grown carbon fiber VGCF, carbon nanotubes (CNTs), and graphene. Non-limitingly, the mass percentage of the positive electrode conductive agent in the positive electrode active layer may be 0–10%, more further 0–8%, even more further 0.1–5%, and even more further 0.5%–3%. In some embodiments, the mass percentage of the positive electrode conductive agent in the positive electrode active layer may be 0.1%–3%.

[0431] In some embodiments, the positive electrode active layer optionally includes a binder. The binder in the positive electrode active layer may be referred to as "positive electrode binder". The positive electrode binder may be a binder known in the art for use in the positive electrode layer of a solid-state battery. As a non-limiting example, the positive electrode binder may include one or more of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene-propylene terpolymer, ethylene-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins. Typically, the mass percentage of the positive electrode binder in the positive electrode active layer may be 0-5%, optionally 0-3%, and more preferably 0-2%. In some embodiments, the mass percentage of the positive electrode binder in the positive electrode active layer is 0.1%-5%, may also be 0.5%-3%, and more preferably 0.5%-2%.

[0432] In some embodiments, the positive electrode layer includes a positive electrode current collector and a positive electrode active layer disposed on at least one surface of the positive electrode current collector. As a non-limiting example, the positive electrode current collector has two surfaces that are opposite to each other in its own thickness direction, and the positive electrode active layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0433] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. In the positive electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the positive electrode current collector, the composite current collector may be obtained by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the positive electrode current collector may include at least one of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limitingly, in the positive electrode current collector, the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0434] Positive electrode sheets can be prepared using dry methods. For example, they can be dry-pressed into membranes.

[0435] In some embodiments, the positive electrode sheet can be prepared by dry mixing the components used to prepare the positive electrode sheet, such as the positive active material, the positive electrolyte material, the positive conductive agent, the positive binder, and any other components, and rolling them into a positive electrode sheet.

[0436] In some embodiments, the positive electrode sheet can be prepared by: dry mixing the components used to prepare the positive electrode sheet, such as the positive electrode active material, positive electrode electrolyte material, positive electrode conductive agent, positive electrode binder, and any other components; then heating and pressurizing the mixed material to knead it into a clump; hot rolling pressing to form a self-supporting positive electrode sheet; and hot rolling bonding the self-supporting positive electrode sheet with a positive electrode current collector, wherein the self-supporting positive electrode sheet can be bonded to at least one side (single or double sides) of the positive electrode current collector to obtain the positive electrode sheet. Non-limitingly, a dual planetary mixer can be used for dry mixing. Non-limitingly, a kneading and pressing process can be performed using a Banbury mixer. Non-limitingly, the temperature for hot rolling pressing can be 75°C to 85°C, and further, such as 78°C, 80°C, 82°C, etc.

[0437] The following is a description of the negative electrode layer.

[0438] The negative electrode layer can be formed based on a solid electrolyte membrane or provided by a pre-fabricated negative electrode sheet, which can be a negative electrode sheet that is available in the art for solid-state batteries.

[0439] In this application, unless otherwise specified, the negative electrode layer includes at least a negative electrode active layer.

[0440] In this application, unless otherwise stated, the negative electrode sheet includes at least a negative electrode active layer.

[0441] Unless otherwise stated in this application, the negative electrode active layer includes at least a negative electrode active material.

[0442] Non-limiting, the negative electrode active layer may include a solid electrolyte material. In this application, unless otherwise specified, the solid electrolyte material in the negative electrode active layer may be referred to as "negative electrode electrolyte material".

[0443] Non-limiting, the mass percentage content of the negative electrode active material in the negative electrode active layer can be ≥80%, and more preferably ≥90%. Non-limiting, the mass percentage content of the negative electrode active material in the negative electrode active layer can be 80% to 99%, optionally 90% to 99%, and more preferably 95% to 99%, and can also be any of the following percentages or a range selected from any two of the following percentages: 80%, 82%, 84%, 85%, 86%, 88%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.

[0444] Non-limitingly, the mass percentage of the negative electrode electrolyte material in the negative electrode active layer can be 0% to 30%, preferably 0.1% to 30%, and further preferably 5% to 20%.

[0445] In some implementations, the negative electrode active material is a lithium indium alloy (InLi alloy).

[0446] In some embodiments, the negative electrode layer or negative electrode sheet is an InLi alloy film.

[0447] In some embodiments, the negative electrode active material may also be a negative electrode active material known in the art for use in solid-state batteries. As a non-limiting example, the negative electrode active material may include one or more of the following materials: elemental silicon, elemental tin, silicon-carbon composites, silicon suboxide, graphite, and metallic lithium. However, this application is not limited to these materials or substances, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0448] In some embodiments, the negative electrode sheet may include a negative current collector and a negative active layer disposed on at least one surface of the negative current collector, the negative active layer comprising a negative active material. As a non-limiting example, the negative current collector has two surfaces opposite to each other in its own thickness direction, and the negative active layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0449] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. In the negative electrode current collector, the composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. In the negative electrode current collector, the composite current collector may be formed by forming a metal material on the polymer material substrate. Non-limiting examples of the metal material in the negative electrode current collector may include at least one of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. Non-limitingly, in the negative electrode current collector, the polymer material substrate may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0450] In some embodiments, the negative electrode active layer optionally includes a conductive agent (which may be referred to as a negative electrode conductive agent). Non-limitingly, the negative electrode conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. Non-limitingly, the mass percentage of the negative electrode conductive agent in the negative electrode active layer may be 0–15%, more preferably 0–10%, and even more preferably 0–5%.

[0451] In some embodiments, the negative electrode active layer optionally includes an adhesive (denoted as negative electrode adhesive). As a non-limiting example, the negative electrode adhesive may include one or more of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS). Non-limitingly, the mass percentage of the negative electrode adhesive in the negative electrode active layer may be 0-10%, more further 1%-10%, even more further 1%-5%, and even more preferably 1%-3%.

[0452] In some embodiments, the negative electrode active layer may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)). The mass percentage of the other additives in the negative electrode active layer may be 0–15%, more preferably 0–10%, even more preferably 0–5%, even more preferably 0–3%, and even more preferably 0–2%.

[0453] Negative electrode sheets can be prepared using either dry or wet methods. For example, they can be dry-pressed into films under low pressure conditions, such as 1 MPa to 2 MPa. Alternatively, they can be wet-coated into films.

[0454] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as negative electrode active material, negative electrode conductive agent, negative electrode binder, and any other components, in a solvent to form a negative electrode slurry. Taking a sulfide-based solid electrolyte as an example, a non-limiting example of a solvent is p-xylene. Further, the negative electrode slurry is coated onto at least one surface of the negative electrode current collector, and after drying or other processes, the negative electrode sheet is obtained. The surface of the negative electrode current collector coated with the negative electrode slurry can be a single surface of the negative electrode current collector or both surfaces of the negative electrode current collector.

[0455] The following is a description of the solid electrolyte layer.

[0456] A solid electrolyte layer can be introduced by forming electrode layers on both sides of the solid electrolyte membrane, or it can be introduced on the electrode layer.

[0457] The solid electrolyte layer acts as a conductor of ions between the positive and negative electrode layers, and can also isolate the positive and negative electrode layers to prevent short circuits between them.

[0458] It is understood that the solid electrolyte layer includes a solid electrolyte material. The solid electrolyte material in the solid electrolyte layer can be any solid electrolyte material known in the art that can be used in solid-state batteries.

[0459] The types of solid electrolyte materials present in different film layers of a solid-state battery can be the same or different. For example, the solid electrolyte materials in the positive electrode layer and the solid electrolyte layer can be the same or different. As a non-limiting example, the solid electrolyte materials in different film layers of a solid-state battery can include one or more of the following: sulfide solid electrolytes, halide solid electrolytes, oxide solid electrolytes, and polymer solid electrolytes.

[0460] As a non-limiting example, in different film layers of a solid-state battery, the solid electrolyte material can independently include, but is not limited to, one or more of oxide-based solid electrolytes, sulfide-based solid electrolytes, and halide-based solid electrolytes. In some embodiments, the solid electrolyte material can independently include, but is not limited to, one or more of Argyrodite-type sulfide electrolytes and halide electrolytes. Non-limiting examples of oxide-based solid electrolytes may include LISICON-type oxide electrolytes (such as γ-Li3PO4), NASICON-type oxide electrolytes (such as Li... 1+δ5 Al δ5 Ge 2-δ5 (PO4)3,Li 1+δ5 Al δ5 Ti 2-δ5(PO4)3, etc., 0≤δ5≤1), Garnet type (such as Li7La3Zr2O) 12 (etc.), perovskite-type oxide electrolytes (such as Li, etc.) 3·δ6 La 2 / 3-δ6 One or more of the following: TiO3, etc., 0≤δ6≤0.5). Non-limiting examples of sulfide solid electrolytes may include Li. 10 GeP2S 12 Li₂S-P₂S₅, Li₇P₃S 11 Argyrodite type (such as Li6PS5Cl, Li 5.5 PS 5.5 Cl 1.5 Li 5.7 PS5Cl 1.3 One or more of the following, and may also include sulfide solid electrolytes as described in the context. Non-limiting examples of halide solid electrolytes may include one or more of the following: Li3InCl6, Li3YCl6, Li3ScCl6, Li3ErCl6, Li2ZrCl6, etc.

[0461] In some embodiments, the sulfide solid electrolyte includes one or more of the following: silver sulfide-germanium sulfide type sulfide electrolyte, LGPS type sulfide electrolyte, and lithium pentaphosphine sulfide complex type sulfide electrolyte. Non-limitingly, the lithium pentaphosphine sulfide complex type sulfide electrolyte may include the chemical formula (100-uv)Li₂S·uP₂S₅·vM. 3 m N 3 n Sulfide electrolytes, of which 0 <u<100,0≤v<100,0≤u+v<100,0≤m<4,0≤n<6,M 3 It can be selected from, but is not limited to, one or more elements from Li, B, Ge, Si, Sn, and Sb, N 3 It can be selected from one or more elements from S, Se, Te, O, Cl, Br, I, and F.

[0462] Solid electrolyte membranes or solid electrolyte layers can be prepared using dry methods. In some embodiments, the solid electrolyte layer can be formed by pressing solid electrolyte materials into a solid electrolyte membrane. In other embodiments, the solid electrolyte layer is formed by pressing the constituent materials of the solid electrolyte layer onto an electrode layer.

[0463] Solid electrolyte layers can also be prepared using a wet process. The electrolyte slurry used includes at least a solid electrolyte material and an organic solvent, and usually also includes one or more of a binder and a dispersant.

[0464] In a non-limiting manner, the positive electrode layer, the solid electrolyte layer, and the negative electrode layer can be assembled in a stacked manner, with the solid electrolyte layer placed between the positive electrode layer and the negative electrode layer.

[0465] Solid-state batteries are prepared using methods including, but not limited to, those described in the fourth aspect of this application.

[0466] Non-limitingly, a solid-state battery cell can be prepared by sequentially placing a positive electrode, a solid electrolyte material layer, and a negative electrode, with the solid electrolyte material layer placed between the positive and negative electrode, and then pressing them together.

[0467] In some embodiments, the solid-state battery may include an outer packaging. This outer packaging can be used to encapsulate the aforementioned solid-state battery cell.

[0468] In some embodiments, the outer packaging of a solid-state battery can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of a solid-state battery can also be a soft pack, such as a pouch-type soft pack. The material of the soft pack can be plastic; further, non-limiting examples of plastics may include one or more of polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0469] This application does not impose any particular limitation on the shape of the solid-state battery cell; it can be cylindrical, square, or any other arbitrary shape. For example, Figure 1 This is an example of a square-structured solid-state battery cell 5.

[0470] In some of these implementations, reference is made to... Figure 2 The outer packaging may include a housing 51 and a cover 53. The housing 51 may include a base plate and side plates connected to the base plate, the base plate and side plates forming a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover 53 can be placed over the opening to close the receiving cavity. A solid-state battery cell 52 is encapsulated within the receiving cavity. The number of solid-state battery cells 52 contained in a single solid-state battery cell 5 may be one or more, which can be selected by those skilled in the art according to actual needs.

[0471] Solid-state batteries can be battery device 4 or battery pack 1.

[0472] The battery device includes at least one solid-state battery cell. The number of solid-state battery cells in the battery device can be one or more, and those skilled in the art can select an appropriate number according to the application and capacity of the battery device.

[0473] Figure 3 This is battery device 4, used as an example. (See reference...) Figure 3In the battery device 4, multiple solid-state battery cells 5 can be arranged sequentially along the length of the battery device 4. Of course, they can also be arranged in any other manner. Furthermore, the multiple solid-state battery cells 5 can be fixed in place using fasteners.

[0474] Optionally, the battery device 4 may also include a housing with a receiving space in which a plurality of solid-state battery cells 5 are housed.

[0475] In some embodiments, the battery devices described above can also be assembled into a battery pack, and the number of battery devices contained in the battery pack can be one or more. Those skilled in the art can select an appropriate number according to the application and capacity of the battery pack.

[0476] Figure 4 and Figure 5 This is battery pack 1 as an example. (See reference...) Figure 4 and Figure 5 The battery pack 1 may include a battery box and multiple battery devices 4 disposed within the battery box. The battery box includes an upper body 2 and a lower body 3, with the upper body 2 covering the lower body 3 to form a closed space for accommodating the battery devices 4. The multiple battery devices 4 can be arranged in any manner within the battery box.

[0477] In a second aspect of this application, a doped / coated modified oxide-based positive electrode active material is provided, which includes the characteristics of the doped / coated modified oxide-based positive electrode active material in solid-state batteries described in the first aspect of this application.

[0478] In a third aspect of this application, a positive electrode sheet is provided, which includes a positive active layer, the positive active layer including the characteristics of the positive active layer in the solid-state battery described in the first aspect of this application.

[0479] In a fourth aspect of this application, a method for preparing a solid-state battery is provided, comprising the following steps: stacking a positive electrode, a solid electrolyte material layer and a negative electrode in sequence, pressing them together to prepare a solid-state battery;

[0480] The positive electrode includes a positive active layer, which comprises a positive active material and a positive electrolyte material. The positive electrolyte material includes a sulfide solid electrolyte. The positive active material includes a doped / coated modified oxide positive active material, which comprises a positive active body and a coating layer located on at least a portion of the surface of the positive active body. The positive active body includes a doped oxide positive active material, which includes a doping element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material. The oxygen-absorbing material includes an oxide-type oxygen-absorbing material. The solid electrolyte raw material layer comprises a solid electrolyte material.

[0481] In some embodiments, the positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery described in the first aspect of this application.

[0482] In some embodiments, the solid electrolyte raw material layer includes a solid electrolyte material and optionally includes a binder.

[0483] In some embodiments, the doped / coated modified oxide-based positive electrode active material is prepared by a method comprising the following steps:

[0484] The oxide-based positive electrode active material raw material and the dopant source are ultrasonically dispersed, stirred, and dried in a first solvent to remove the first solvent, obtaining a preliminary mixture; the preliminary mixture is annealed in an oxygen-containing atmosphere to prepare a doped oxide-based positive electrode active material; wherein, the dopant source includes a dopant element;

[0485] Doped / coated modified oxide-based positive electrode active materials are prepared by dry ball milling and mixing with carbon composite oxygen-absorbing materials.

[0486] Those skilled in the art can select a suitable doping source based on the type of dopant element. Taking cerium doping as an example, the doping source may include one or more of cerium dioxide, cerium trioxide, cerium carbonate, cerium chloride, cerium fluoride, cerium sulfate, and cerium nitrate.

[0487] In some embodiments, the first solvent includes one or more of ethanol, toluene, methanol, and dimethyl ether.

[0488] In some embodiments, the rotational speed for dry ball milling is 300 rpm to 600 rpm, and may also be any of the following rotational speeds or a range selected from any two of the following rotational speeds: 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, etc.

[0489] In some embodiments, the ball milling time for dry ball milling can be 12h to 36h, or any of the following times or a range selected from any two of the following times: 12h, 14h, 15h, 16h, 18h, 20h, 22h, 24h, 25h, 26h, 8h, 30h, 32h, 34h, 35h, 36h, etc.

[0490] In some embodiments, the annealing temperature is 400°C to 800°C, or any of the following temperatures or a range selected from any two of the following temperatures: 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, etc.

[0491] In some implementations, the annealing process takes 2 hours to 12 hours, and may also take any of the following durations or be selected from any two of the following durations: 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc.

[0492] In some embodiments, the carbon composite oxygen-absorbing material is prepared by a method comprising the following steps: mixing a carbon conductive material raw material and an oxygen-absorbing material raw material in a second solvent, performing liquid-phase ball milling, and drying to remove the second solvent, thereby obtaining the carbon composite oxygen-absorbing material. Non-limitingly, the second solvent may include one or more of ethanol, toluene, methanol, and dimethyl ether. Non-limitingly, the rotational speed for liquid-phase ball milling is 300 rpm to 600 rpm, and may also be any of the following rotational speeds or a range selected from any two of the following rotational speeds: 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, 550 rpm, 600 rpm, etc. Non-limitingly, the ball milling time is 12h to 36h, and may also be any of the following times or a range consisting of any two of the following times: 12h, 14h, 15h, 16h, 18h, 20h, 22h, 24h, 25h, 26h, 8h, 30h, 32h, 34h, 35h, 36h, etc.

[0493] In some embodiments, the method for fabricating solid-state batteries satisfies one or more of the following characteristics (any numerical parameter of the following characteristics may also be selected from any suitable value or range in the context):

[0494] (k1) The first solvent includes one or more of ethanol, toluene, methanol and dimethyl ether;

[0495] (k2) The rotation speed for dry ball milling is 300 rpm to 600 rpm;

[0496] (k3) The ball milling time for dry ball milling is 12h to 36h;

[0497] (k4) The annealing temperature is 400℃~800℃;

[0498] (k5) The annealing time is 2h to 12h;

[0499] (k6) The carbon composite oxygen-absorbing material is prepared by a method including the following steps: mixing carbon conductive material raw material and oxygen-absorbing material raw material in a second solvent, performing liquid-phase ball milling, and drying to remove the second solvent to prepare the carbon composite oxygen-absorbing material; optionally, the second solvent includes one or more of ethanol, toluene, methanol, and dimethyl ether; optionally, the rotation speed of the liquid-phase ball milling is 300 rpm to 600 rpm, and the ball milling time is 12 h to 36 h;

[0500] (k7) The electronic conductivity of carbon composite oxygen-absorbing material at 25℃ is ≥5mS / cm;

[0501] (k8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising a doped / coated modified oxide positive electrode active material and a sulfide solid electrolyte, and forming a film under solvent-free conditions; wherein, the positive electrode material composition may optionally include one or more of a binder and a conductive agent;

[0502] (k9) The solid-state battery described in the first aspect of this application is prepared.

[0503] Liquid-phase ball milling allows carbon conductive materials and oxygen-absorbing materials to be combined more effectively and stably.

[0504] The size and size distribution of the carbon conductive material or oxygen-absorbing material raw material can be controlled according to the relevant description of doped / coated modified oxide cathode active materials in the first aspect of this application. Particle size and distribution can be controlled by combining methods such as sieving and ball milling.

[0505] The maximum and average particle size of carbon conductive or oxygen-absorbing raw materials can be tested using the following method: The powder sample of the material to be tested is adhered to conductive adhesive and subjected to scanning electron microscopy (SEM testing, such as with a Phenom-XL G2 microscope) at a magnification of 500X to 30000X (i.e., 500X to 30kX). The maximum diameter of the selected particle in each direction of the SEM image is recorded as the "maximum particle size". Multiple particles can be selected for statistical analysis. The distribution range of the maximum particle size of the counted particles is recorded; the number of counted particles can be at least 5, and optionally at least 10. The average of the "maximum particle sizes" of multiple particles is taken to obtain the "average particle size" of the material to be tested. For example, scanning electron microscopes (SEM) such as the Phenom-XL G2, ZEISS Sigma300, JEOL, and AxiaChemiSEM can be used.

[0506] In some embodiments, the carbon composite oxygen-absorbing material has an electronic conductivity of ≥5 mS / cm at 25°C.

[0507] In this application, "electronic conductivity" has a well-known meaning in the art and can be used to characterize the strength of a material's ability to transport electrons; the higher the electronic conductivity, the stronger the electron conduction ability. Electronic conductivity can be expressed as σ. The electronic conductivity of materials can be tested using methods and instruments already available in the art. Unless otherwise specified, the test temperature is 25°C.

[0508] Electronic conductivity can be tested as follows: The solid powder of the material to be tested is placed in a test mold, with stainless steel gaskets used as blocking electrodes on both sides, and pressed into a conductivity mold battery. Electronic conductivity can be obtained by constant-voltage DC testing of the mold battery using an electrochemical workstation; the electronic conductivity σ is calculated using the following formula: σ = d / (R × S), where R represents the electrochemical impedance (the electronic impedance value is measured by the electrochemical workstation), d is the length along the current conduction direction (corresponding to the thickness of the film structure), and S is the cross-sectional area perpendicular to the current conduction direction (corresponding to the effective area).

[0509] Unless otherwise specified, the electronic conductivity of the carbon composite oxygen-absorbing material at 25°C can be tested under the following pressing conditions: pressing at 350 MPa for 3 minutes to form a film.

[0510] In some embodiments, the positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising a doped / coated modified oxide positive electrode active material and a sulfide solid electrolyte, and forming a membrane under solvent-free conditions; wherein the positive electrode material composition may optionally include one or more of a binder and a conductive agent.

[0511] Non-limitingly, in the doped / coated modified oxide-based positive electrode active material used to prepare the positive electrode layer of the solid-state battery, x2 can be any of the following values, or a range selected from any two of the following values: 0.98, 0.99, 1.00, 1.01, 1.02, etc., or any range selected from: 0.98 to 1.02, etc. In some embodiments, x2 is 1.

[0512] Non-limitingly, in the doped / coated modified oxide-based positive electrode active material used to prepare the positive electrode layer of the solid-state battery, x3 can be any of the following values, or a range selected from any two of the following values: 1.96, 1.97, 1.98, 1.99, 2.00, 2.01, 2.02, 2.03, 2.04, etc., or any of the following ranges: 1.96–2.04, 1.98–2.02, 1.99–2.01, etc. In some embodiments, x3 is 2.

[0513] In a fifth aspect of this application, an electrical device is provided, comprising at least one of the solid-state battery described in the first aspect of this application, the doped / coated modified oxide-based positive electrode active material described in the second aspect of this application, the positive electrode sheet described in the third aspect of this application, and a solid-state battery prepared by the method for preparing a solid-state battery described in the fourth aspect of this application.

[0514] In some embodiments, the electrical device includes at least one of the solid-state batteries of any of the embodiments provided in this application.

[0515] In a non-limiting sense, solid-state batteries can be used as a power source for electrical devices or as an energy storage unit for electrical devices. Electrical devices can include, but are not limited to, mobile devices, electric vehicles, electric trains, ships and satellites, energy storage systems, etc. Mobile devices can be, for example, mobile phones, laptops, etc.; electric vehicles can be, for example, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric motorcycles, power tools, etc., but are not limited to these. This electrical device can also be applied to military equipment, aerospace, and other fields, and can also be applied to energy storage power systems such as hydroelectric, thermal, wind, and solar power plants.

[0516] As an electrical device, solid-state batteries can be selected based on its usage requirements.

[0517] Figure 6 Here is an example of an electrical device 6. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc. To meet the high power and high energy density requirements of this electrical device for solid-state batteries, a battery device or battery pack can be used.

[0518] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a thin and light design and can use solid-state batteries as their power source.

[0519] The following describes some embodiments of this application. The described embodiments are only a part of the embodiments of this application, and not all of them. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application and its applications. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0520] Unless otherwise specified in the examples, the procedures described above, or those described in the literature in this field, or those described in the product instructions, shall be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products, or products that can be synthesized using conventional methods from commercially available products.

[0521] In the following examples, room temperature refers to 20°C to 30°C.

[0522] It should be noted that the following embodiments and examples use all-solid-state batteries as non-limiting examples of solid-state batteries, and further use all-solid-state lithium-ion secondary batteries as examples. Unless otherwise stated, aluminum foil is used as the positive electrode current collector.

[0523] In the following examples, unless otherwise specified, the use of organic solvents to disperse sulfide solid electrolyte materials is involved. The organic solvent may be one or more of xylene, trimethylbenzene, butyl butyrate, heptane, etc., and may further be pseudotrimethylbenzene or p-xylene.

[0524] In the following embodiments and comparative examples, unless otherwise stated, the steps involving sulfide solid electrolytes and materials or films containing them are carried out in an argon atmosphere.

[0525] In the following examples, unless otherwise specified, the parameters involved can be confirmed and / or adjusted with reference to the test methods described above. For example, the parameters involved include the electronic conductivity of carbon composite oxygen-absorbing materials at 25°C, coating layer-related parameters (average thickness of the coating layer), oxygen vacancy index of oxygen-absorbing materials, average and maximum particle size of carbon conductive materials and their raw materials, and average and maximum particle size of oxygen-absorbing materials and their raw materials.

[0526] In the following examples, the maximum particle size of the carbon conductive material raw material is less than or equal to 0.5 μm, the maximum particle size of the oxygen-absorbing material is less than or equal to 200 nm, the average particle size of the carbon conductive material is in the range of 5 nm to 0.21 μm, and the average particle size of the oxygen-absorbing material is in the range of 10 nm to 50 nm.

[0527] Example 1.

[0528] 1. Preparation of carbon composite oxygen-absorbing materials.

[0529] The carbon conductive material raw material was ultrasonically dispersed in ethanol (as a second solvent) for 20 minutes. Then, a certain mass ratio of oxygen-absorbing material raw material was added. After thorough stirring, the mixture was transferred to a ball mill jar for liquid-phase ball milling at 400 rpm for 24 hours. After ball milling, the mixture was vacuum dried at 80°C to completely remove the ethanol, thus obtaining the carbon composite oxygen-absorbing material.

[0530] In this example, the carbon conductive material is vapor-grown carbon fiber (VGCF), and the oxygen-absorbing material is nano-cerium oxide. The mass ratio of the carbon conductive material to the oxygen-absorbing material is (R... 12 The figure is 1%.

[0531] In this example, the average particle size of the carbon conductive material raw material VGCF is approximately 0.1 μm, ranging from 5 nm to 0.1 μm and also from 30 nm to 0.1 μm; the maximum particle size of the carbon conductive material raw material VGCF is in the range of 50 nm to 0.3 μm; the average particle size of the oxygen-absorbing material raw material is approximately 20 nm, ranging from 10 nm to 20 nm; the maximum particle size of the oxygen-absorbing material raw material is in the range of 5 nm to 50 nm, and 80% of the maximum particle size is in the range of 30 nm to 50 nm.

[0532] Among them, the mass ratio of carbon conductive material raw material to oxygen-absorbing material raw material (R) 12 The mass percentage (R) of carbon conductive material relative to oxygen-absorbing material in carbon composite oxygen-absorbing materials. 10 They are basically equal.

[0533] 2. Preparation of doped oxide-based positive electrode active materials

[0534] According to a certain mass ratio, oxide-based positive electrode active material raw materials (NCM) are mixed. 811 LiNi 0.8 Co 0.1 Mn 0.1 O2 and the dopant source are ultrasonically dispersed in ethanol, stirred overnight (12h-16h), and then vacuum dried at 80℃ to remove ethanol, resulting in a uniformly mixed material. The mixture is then annealed at 700℃ for 4h under an oxygen flow to obtain a doped oxide-type positive electrode active material with doped elements on its surface.

[0535] In this example, the doping source is cerium carbonate, the doping element is cerium (Ce), and the resulting doped oxide-type positive electrode active material is Ce-doped NCM. 811 Materials, NCM 811 The surface is doped with cerium ions.

[0536] The amount of dopant source used is based on the "mass percentage (F) of the dopant element in the cathode active material" in the doped / coated modified oxide cathode active material. X0 The target value is selected based on the mass ratio (R) of the dopant source to the oxide-based positive electrode active material. X0 If F is 1%, then F X0 Approximately 0.3%.

[0537] 3. Doped / coated modified oxide-based positive electrode active materials (as positive electrode active materials)

[0538] Carbon composite oxygen-absorbing material and oxide-based positive electrode active material are mixed by dry ball milling at a certain mass ratio of 400 rpm for 24 hours to prepare doped / coated modified oxide-based positive electrode active material.

[0539] The mass ratio of carbon composite oxygen-absorbing material to oxide-based positive electrode active material (R) 20 According to the mass percentage (F) of carbon composite oxygen-absorbing material in the target product of doped / coated modified oxide cathode active material, 20 Select the appropriate mass ratio.

[0540] In this example, the oxide-based positive electrode active material is NCM. 811 (LiNi0.8 Co 0.1 Mn 0.1 O2), the mass ratio of carbon composite oxygen-absorbing material to oxide-based positive electrode active material R 20 It is 2% (corresponding to F) 20 Approximately 1.96%). In this example, the mass percentage (F) of the coating layer in the doped / coated modified oxide cathode active material. 10 ) and F 20 The mass percentages of carbon conductive material to oxygen-absorbing material in the coating layer are essentially equal (R0). 11 ) and R 10 They are basically equal.

[0541] In this example, the average thickness of the coating layer is approximately 20 nm.

[0542] 4. Preparation of positive electrode sheet

[0543] The cathode was prepared using a dry method. The prepared composite-coated cathode material was used as the cathode active material.

[0544] The positive electrode active material, sulfide-based solid electrolyte Li6PS5Cl conductive agent (vapor-grown carbon fiber (VGCF)), and binder (polytetrafluoroethylene (PTFE)) were mixed evenly in a mass ratio of 70:26:3:1 and rolled into a positive electrode sheet. The positive electrode surface capacity was 3 mAh / cm². 2 .

[0545] 5. Negative electrode plate

[0546] A lithium-indium alloy sheet is used, wherein the molar ratio of Li to In is 1:3.

[0547] 6. Assemble solid-state batteries, which are all-solid-state lithium-ion secondary batteries.

[0548] In a molded battery system, the positive electrode sheet, the solid electrolyte material layer (Li6PS5Cl), and the negative electrode sheet are placed in the order of positive electrode layer, solid electrolyte layer, and negative electrode layer from top to bottom, and then pressed into shape under a pressure of 100MPa to obtain a solid-state battery. Subsequently, it is packaged in a molded battery fixture with an external pressure of 50MPa for battery performance testing.

[0549] Examples 2-7. Doped / coated modified oxide-based positive electrode active materials, positive electrode sheets, and solid-state batteries were prepared using essentially the same method as in Example 1, the difference being: changing R... X0 (corresponding changes to F) X0 ), change R 12 (corresponding changes to R) 10 and R 11 ) or change R 20 (corresponding changes to F) 20 and F10 Different doped / coated modified oxide-based positive electrode active materials were obtained, and these were used to prepare positive electrode sheets and solid-state batteries. The remaining operation steps were the same as in Example 1, and can be found in Tables 1-2.

[0550] Example 2-3: Change R X0 .

[0551] Example 4-5: Change R 20 .

[0552] In Example 4, the average thickness of the coating layer is approximately 10 nm.

[0553] In Example 5, the average thickness of the coating layer is approximately 50 nm.

[0554] Example 6-7: Change R 12 .

[0555] Examples 8-9. Doped / coated modified oxide-based positive electrode active materials, positive electrode sheets, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference was that the doping source was changed to provide different doping elements, and oxide-type oxygen-absorbing materials with the same doping elements were used to obtain different doped / coated modified oxide-based positive electrode active materials, which were then used as different positive electrode active materials to prepare positive electrode sheets and solid-state batteries. The remaining operation steps were the same as in Example 1, as shown in Tables 1-2.

[0556] In Example 8, the doping element is Fe, the doping source is Fe2O3, the oxygen absorbing material is Fe2O3, the maximum particle size ranges from 10nm to 200nm, 80% of the maximum particle size is in the range of 30nm to 200nm, and the average particle size is about 20nm.

[0557] In Example 9, the doping element is Ti, the doping source is TiO2, the oxygen absorbing material is TiO2, the maximum particle size ranges from 10nm to 200nm, 80% of the maximum particle size is in the range of 30nm to 200nm, and the average particle size is about 15nm.

[0558] Example 10. A doped / coated modified oxide-based positive electrode active material, positive electrode sheet, and solid-state battery were prepared using essentially the same method as in Example 1. The difference was that the type of carbon conductive material raw material was changed to obtain different doped / coated modified oxide-based positive electrode active materials, which were then used as different positive electrode active materials to prepare positive electrode sheets and solid-state batteries. The remaining operational steps were the same as in Example 1, as shown in Tables 1-2.

[0559] In Example 10, the carbon conductive material raw material is carbon nanotubes, with the maximum particle size ranging from 5 nm to 50 nm, 80% of the maximum particle size ranging from 20 nm to 50 nm, and the average particle size (based on the average of the maximum particle size) is approximately 10 nm.

[0560] Examples 11-14. Doped / coated modified oxide-based positive electrode active materials, positive electrode sheets, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference lies in changing the dimensions of the carbon conductive material and the oxygen-absorbing material to obtain different doped / coated modified oxide-based positive electrode active materials, which were then used as different positive electrode active materials to prepare positive electrode sheets and solid-state batteries. The remaining operational steps are the same as in Example 1, as shown in Tables 1-2.

[0561] In Example 11, the oxygen-absorbing material, cerium oxide nanoparticles, had a maximum particle size ranging from 10 nm to 60 nm, with 80% of the maximum particle size falling within the range of 30 nm to 60 nm, and an average particle size of approximately 14 nm. The carbon conductive material, VGCF, was the same as in Example 1. The average particle size was calculated as the average of the maximum particle sizes of all statistically analyzed particles.

[0562] In Example 12, the oxygen-absorbing material, cerium oxide nanoparticles, had a maximum particle size ranging from 30 nm to 0.2 μm, with 80% of the particles having a maximum particle size ranging from 60 nm to 0.2 μm, and an average particle size of approximately 46 nm; the carbon conductive material, VGCF, was the same as in Example 1.

[0563] In Example 13, the maximum particle size of the carbon conductive material VGCF is in the range of 8 nm to 200 nm, and the average particle size is about 0.1 μm. The oxygen-absorbing material nano-cerium oxide is the same as in Example 1.

[0564] In Example 14, the maximum particle size of the carbon conductive material VGCF is in the range of 300 nm to 0.5 μm, and the average particle size is about 0.2 μm; the oxygen-absorbing material nano-cerium oxide is the same as in Example 1.

[0565] Example 15. Doped / coated modified oxide cathode active materials, cathode electrodes, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference was that the oxygen vacancy index of the cerium oxide was changed to obtain different doped / coated modified oxide cathode active materials, which were then used as different cathode active materials to prepare cathode electrodes and solid-state batteries. The remaining operation steps were the same as in Example 1, as shown in Tables 1-2.

[0566] In Example 15, the oxygen-absorbing material is made from cerium oxide (CeO). 1.75 The oxygen vacancy index is 0.25, the average particle size is about 12 nm, the maximum particle size ranges from 5 nm to 70 nm, and 80% of the maximum particle size is in the range of 30 nm to 70 nm.

[0567] Example 16. Doped / coated modified oxide-based positive electrode active materials, positive electrode sheets, and solid-state batteries were prepared using essentially the same method as in Example 1, except that the raw material for the oxide-based positive electrode active material was NCM. 90 / 5 / 5 (LiNi 0.90 Co 0.05 Mn 0.05 O2) was used to obtain different doped / coated modified oxide-based positive electrode active materials, which were then used to prepare positive electrode sheets and solid-state batteries. The remaining operation steps were the same as in Example 1, and can be found in Tables 1-2.

[0568] Example 17. Doped / coated modified oxide-based positive electrode active material, positive electrode sheet, and solid-state battery were prepared using essentially the same method as in Example 1, except that the raw material for the oxide-based positive electrode active material was NCM. 622 (LiNi 0.6 Co 0.2 Mn 0.2 O2) was used to obtain different doped / coated modified oxide-based positive electrode active materials, which were then used to prepare positive electrode sheets and solid-state batteries. The remaining operation steps were the same as in Example 1, and can be found in Tables 1-2.

[0569] Examples 18-20: Changing the combination of doping elements and oxygen-absorbing substances.

[0570] Doped / coated modified oxide cathode active materials, cathode electrodes, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference lies in changing the combination of doping elements and oxygen-absorbing substances to obtain different doped / coated modified oxide cathode active materials, which were then used as different cathode active materials to prepare cathode electrodes and solid-state batteries. The remaining operational steps are the same as in Example 1, as shown in Tables 1-2.

[0571] In Example 18, the doping element was Ce, the doping source was cerium carbonate, and the oxygen-absorbing substance was replaced with Fe2O3 from Example 8.

[0572] In Example 19, the doping element is Ce, the doping source is cerium carbonate, and the oxygen-absorbing material is replaced with TiO2 from Example 9.

[0573] In Example 20, the doping element is Fe, the doping source is the same as in Example 8, and the oxygen-absorbing substance is cerium oxide from Example 1.

[0574] Example 21. Changing the combination of doping elements and oxygen-absorbing substances.

[0575] Doped / coated modified oxide cathode active materials, cathode electrodes, and solid-state batteries were prepared using essentially the same method as in Example 1. The difference lies in changing the combination of doping elements and oxygen-absorbing substances to obtain different doped / coated modified oxide cathode active materials, which were then used as different cathode active materials to prepare cathode electrodes and solid-state batteries. The remaining operational steps are the same as in Example 1, as shown in Tables 1-2.

[0576] In Example 21, the doping element is Zr, the doping source is ZrO2, and the oxygen-absorbing substance is cerium oxide from Example 1.

[0577] Comparative Example 1. No doping, no coating.

[0578] The positive electrode and solid-state battery were prepared using essentially the same method as in Example 1, except that doping and coating were omitted, and NCM was used instead of the method described in Example 1. 811 The raw materials were used as positive electrode active materials to prepare the positive electrode sheet and solid-state battery. The remaining operation steps were the same as in Example 1, and can be found in Tables 1-2.

[0579] Comparative Example 2. Doping only, coating omitted.

[0580] The positive electrode and solid-state battery were prepared using essentially the same method as in Example 1, except that a doped oxide-based positive electrode active material was used as the positive electrode active material. The remaining operational steps were the same as in Example 1, as shown in Tables 1-2.

[0581] Comparative Example 3. Only coating, doping omitted.

[0582] The positive electrode and solid-state battery were prepared using essentially the same method as in Example 1, except that NCM was used in Example 1. 811 The raw materials used in Example 1 were replaced with doped oxide-based positive electrode active materials to prepare doped / coated modified oxide-based positive electrode active materials, which were then used to prepare positive electrode sheets and solid-state batteries as different positive electrode active materials. The remaining operating steps were the same as in Example 1, as shown in Tables 1-2.

[0583] Comparative Example 4. No doping, no coating.

[0584] The positive electrode and solid-state battery were prepared using essentially the same method as in Example 16, except that doping and coating were omitted, and NCM was used instead. 90 / 5 / 5 (LiNi 0.90 Co 0.05 Mn 0.05 O2 was used as the positive electrode active material to prepare the positive electrode sheet and solid-state battery. The remaining operation steps were the same as in Example 1, and can be found in Tables 1-2.

[0585] Comparative Example 5. No doping, no coating.

[0586] The positive electrode and solid-state battery were prepared using essentially the same method as in Example 17, except that doping and coating were omitted, and NCM was used instead. 622 The positive electrode and solid-state battery were prepared using it as the positive electrode active material. The remaining operation steps are the same as in Example 1, and can be found in Tables 1-2.

[0587] II. Test and Analysis Methods

[0588] (I) Observation and testing of the coating layer

[0589] (1) Average thickness (D1) of the coating layer of the doped / coated modified oxide cathode active material.

[0590] Instrument: High-resolution transmission electron microscope (HRTEM), model ThermoScientific-TalosF200SG2.

[0591] Test method: Particles of doped / coated modified oxide cathode active materials were cut using an ion beam polisher (Hitachi-IM5000), and HRTEM tests were performed on the resulting cross-sections. A clear boundary was observed at the coating interface, thus distinguishing the bulk cathode active material from the coating layer.

[0592] Statistical analysis method: The average thickness at multiple test locations within each particle is recorded as the coating thickness of that particle. The average coating thickness of multiple particles is then taken as the average coating thickness (D1) of the doped / coated modified oxide cathode active material. The number of doped / coated modified oxide cathode active material particles counted is ≥5. The number of statistical locations within each particle is ≥3.

[0593] (2) Combined energy-dispersive X-ray spectroscopy (EDX analysis)

[0594] Observing the particle cross-section under HRTEM (High-Resolution Transmission Electron Microscopy) reveals a clear boundary at the coating interface, distinguishing the bulk positive electrode active material from the coating layer. Then, using energy-dispersive X-ray spectroscopy (EDX) elemental analysis, the types and distribution locations of dopants in the positive electrode active material and the elements in the coating layer are identified. This allows for the differentiation of carbon conductive materials and oxygen-absorbing materials (including oxide-type oxygen-absorbing materials) in the coating layer. Combined with the elemental distribution profile, parameters such as the coating layer thickness at different locations (for greater precision), the distribution area of ​​dopants relative to the surface of the positive electrode active material, and the sizes of the carbon conductive materials (maximum and average particle sizes) and oxygen-absorbing materials (maximum and average particle sizes) can be measured. The statistical analysis of the average coating layer thickness requires ≥3 statistical locations. The statistical analysis of the maximum particle size of nanoparticles (carbon conductive materials or oxygen-absorbing materials) requires ≥4 particles. The statistical analysis of the average particle size of nanoparticles (carbon conductive materials or oxygen-absorbing materials) requires ≥4 particles.

[0595] The test results of the maximum and average particle sizes of carbon conductive materials and oxygen-absorbing materials are basically consistent with the parameter test results of the corresponding raw materials.

[0596] (II) Electron conductivity of carbon composite oxygen-absorbing materials at 25℃

[0597] The test temperature was 25℃.

[0598] The solid powder of the material to be tested was placed in a test mold, and stainless steel gaskets were used as blocking electrodes on both sides to press it into a conductivity mold battery (pressing conditions: 350MPa for 3min). The AC impedance spectroscopy of the mold battery was measured using an electrochemical workstation. The electronic conductivity σ was calculated according to the following formula: σ = d / (R×S), where R represents the electrochemical impedance (the electronic impedance value was measured by the electrochemical workstation), d is the length along the current conduction direction (corresponding to the thickness of the film structure), and S is the cross-sectional area perpendicular to the current conduction direction (corresponding to the effective area).

[0599] (III) Battery Performance Testing

[0600] The full battery underwent charge-discharge testing on the Blue Battery testing platform: test temperature 25℃; charge-discharge voltage range: 2.6~4.3V vs. Li + / Li, external pressure during testing: 50MPa.

[0601] The test procedure is as follows: After three 0.1C charge-discharge cycles of the full battery (each cycle charging to 4.3V at 0.1C and then discharging to 2.6V at 0.1C), a long-cycle 0.33C charge-discharge test is performed, with each cycle charging to 4.3V at 0.33C and then discharging to 2.6V at 0.33C, recorded as cycles 1, 2, 3, 4, ... n. By collecting and processing the 0.1C charge-discharge data of the first cycle, the 0.1C charging specific capacity and discharging specific capacity can be obtained. The initial coulombic efficiency is obtained based on the ratio of the discharging specific capacity to the charging specific capacity. The capacity retention P at the 200th cycle at 0.33C rate is obtained by dividing the discharging specific capacity of cycle 203 by the discharging specific capacity of cycle 4. 200 .

[0602] The test results were recorded as “0.1C first-cycle charge specific capacity”, “0.1C first-cycle discharge specific capacity”, “0.1C first-cycle coulombic efficiency”, and “capacity retention rate after 200 cycles at 25℃ and 0.33C”.

[0603] III. Test Result Analysis

[0604] The test results can be found in Table 2.

[0605] In the doped / coated modified oxide cathode active materials of each of Examples 1-21, the dopant element is located in the portion 0-50 nm away from the outer surface of the cathode active body.

[0606] In the doped / coated modified oxide cathode active materials of Examples 1-21, the average thickness (D1) of the coating layer is in the range of 5 nm to 60 nm, and in some examples, D1 is in the range of 15 nm to 40 nm. In Example 1, the average thickness (D1) of the coating layer is about 20 nm.

[0607] In all Examples 1-21, the electronic conductivity of the carbon composite oxygen-absorbing material at 25°C is greater than 5 mS / cm.

[0608] The solid-state batteries prepared in Examples 1-21 all exhibited significantly improved cycle performance, with the capacity retention rate after 200 cycles at 25°C and 0.33C showing a correspondingly significant improvement compared to Comparative Examples 1, 4, and 5. In the solid-state batteries of Comparative Example 1 (compared to Examples 1-15, 18-21), Comparative Example 4 (compared to Example 16), and Comparative Example 5 (compared to Example 17), the positive electrode active material was undoped and uncoated.

[0609] In addition, the solid-state batteries prepared in Examples 1-21 not only significantly improved cycle performance but also had high initial coulombic efficiency.

[0610] Compared to Example 1, the positive electrode active material in Comparative Example 2 is only doped and not coated, while the positive electrode active material in Comparative Example 2 is only coated and not doped. The cycle performance of the solid-state battery in Example 1 is significantly better than that of Comparative Examples 2-3. In addition, the first coulombic efficiency of the solid-state battery in Example 1 is also significantly better than that of Comparative Examples 2-3.

[0611] The positive electrode active materials of Comparative Examples 4-5 omit doping and coating compared to the doped / coated modified oxide positive electrode active materials of Examples 16 and 17, that is, they are undoped and uncoated. The cycle performance of Examples 16 and 17 is significantly better than that of Comparative Examples 4 and 5, respectively.

[0612] Table 1.

[0613]

[0614]

[0615] Table 2.

[0616]

[0617]

[0618] In Table 2, D1 represents the average thickness of the coating layer.

[0619] The descriptions of the various implementation methods and embodiments above tend to emphasize the differences between them. Similarities or resemblances can be referenced interchangeably, and for the sake of brevity, they will not be repeated here. The technical features of the implementation methods and embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as the combinations of these technical features do not contradict each other, they should be considered within the scope of this specification.

[0620] It should be noted that this application is not limited to the above-described embodiments and examples. The above-described embodiments and examples are merely examples, and any embodiments and examples that have the same structure and achieve the same effect as the technical concept within the scope of this application are included in the technical scope of this application. The embodiments and examples described above only illustrate several embodiments and examples of this application, and although the descriptions are relatively detailed, they should not be construed as limiting the scope of the patent. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments or examples, and other ways of constructing embodiments or examples by combining some of the constituent elements of the embodiments or examples, are also included in the scope of this application without departing from the spirit of this application.

Claims

1. A solid-state battery, characterized by, It includes a positive electrode layer, the positive electrode layer includes a positive electrode active layer, the positive electrode active layer includes a positive electrode active material and a positive electrode electrolyte material, the positive electrode electrolyte material includes a sulfide solid electrolyte; The positive electrode active material includes a doped / coated modified oxide positive electrode active material, which includes a positive electrode active body and a coating layer located on at least a portion of the surface of the positive electrode active body. The positive electrode active body includes a doped oxide positive electrode active substance, which includes a doping element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material. The oxygen-absorbing material includes an oxide-type oxygen-absorbing material.

2. The solid-state battery of claim 1, wherein, The doping element includes one or more of cerium, iron, titanium, copper and zirconium, and the oxygen-absorbing substance includes one or more of cerium oxide, iron oxide, titanium oxide and yttrium barium copper oxide (YBCO).

3. The solid-state battery according to claim 1 or 2, characterized by The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (a1) The mass percentage of the oxide-type oxygen-absorbing substance relative to the oxygen-absorbing substance in the carbon composite oxygen-absorbing material is 80% to 100%; (a2) The oxygen-absorbing substance includes cerium oxide (CeO). 2-δ1 The cerium oxide CeO 2-δ1 The oxygen vacancy index δ1 is 0–0.5; (a3) The oxygen-absorbing substance includes iron oxide Fe2O 3-δ2 The iron oxide Fe2O 3-δ2 The oxygen vacancy index δ2 is 0–0.7; (a4) the oxygen absorbing substance comprises titanium oxide TiO 2-δ3 , the oxygen vacancy index δ3 of the titanium oxide TiO 2-δ3 is 0 to 0.25; (a5) the oxygen absorbing substance comprises yttrium barium copper oxide YBa2Cu3O 7-δ4 , the oxygen vacancy index δ4 of the yttrium barium copper oxide YBa2Cu3O 7-δ4 is 0 to 0.

5.

4. The solid-state battery according to any one of claims 1 to 3, characterized by At least one of the doping element and the oxide-type oxygen-absorbing material includes cerium; Optionally, the doping element includes cerium, and the oxygen-absorbing material includes cerium oxide; Alternatively, the cerium oxide may include cerium oxide.

5. The solid-state battery according to any one of claims 1 to 4, characterized by The oxygen-absorbing material includes cerium oxide, and the mass percentage of cerium oxide relative to the oxygen-absorbing material in the carbon composite oxygen-absorbing material is 80% to 100%, optionally 90% to 100%.

6. The solid-state battery according to any one of claims 1 to 3, characterized in that, The doping element and the oxide-type oxygen-absorbing material include at least one of the same elements.

7. The solid-state battery according to any one of claims 1 to 6, characterized by The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (b1) The mass percentage of the doping element in the positive electrode active body is 0.1% to 5%; (b2) At least a portion of the dopant elements are located on the surface of the positive electrode active body; optionally, the dopant elements in the positive electrode active body are located at a distance of 0 to 50 nm from the outer surface of the positive electrode active body. (b3) The doping element includes cerium, and the mass percentage of the cerium doping element in the positive electrode active body is 0.1% to 5%.

8. The solid-state battery of claim 7, wherein, The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (b1') The mass percentage of the doping element in the positive electrode active body is 0.1% to 2%; (b2') The doping element in the positive electrode active body is located at a distance of 0-5 nm from the outer surface of the positive electrode active body; (b3') The doping element includes cerium, and the mass percentage of the cerium doping element in the positive electrode active body is 0.1% to 2%.

9. The solid-state battery according to any one of claims 1 to 8, characterized by, The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (c1) In the carbon composite oxygen-absorbing material, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 5%; (c2) In the coating layer, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 5%; (c3) The carbon composite oxygen-absorbing material has a mass percentage content of 80% to 100% in the coating layer; (c4) The sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the coating layer is 80% to 100%.

10. The solid-state battery of claim 9, wherein, The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (c1') In the carbon composite oxygen-absorbing material, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 2.5%; (c2') In the coating layer, the mass percentage of the carbon conductive material relative to the oxygen-absorbing material is 0.5% to 2.5%; (c3') The carbon composite oxygen-absorbing material has a mass percentage content of 80% to 100% in the coating layer; (c4') The sum of the mass percentages of the carbon conductive material and the oxygen-absorbing material in the coating layer is 80% to 100%.

11. The solid-state battery according to any one of claims 1 to 10, characterized in that, The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (d1) The carbon composite oxygen-absorbing material accounts for 0.5% to 5% of the mass of the doped / coated modified oxide-based positive electrode active material; (d2) The coating layer accounts for 0.5% to 5% of the mass of the doped / coated modified oxide cathode active material; (d3) The carbon composite oxygen-absorbing material includes carbon composite cerium oxide, wherein the carbon composite cerium oxide accounts for 0.5% to 5% of the mass of the doped / coated modified oxide positive electrode active material; (d4) The average thickness of the coating layer is 5 nm to 60 nm; (d5) At least a portion of the coating layer has a thickness of 5 nm to 60 nm.

12. The solid-state battery of claim 11, wherein, The doped / coated modified oxide-based positive electrode active material satisfies one or more of the following characteristics: (d1') The carbon composite oxygen-absorbing material accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material; (d2') The coating layer accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide cathode active material; (d3') The carbon composite oxygen-absorbing material includes carbon composite cerium oxide, wherein the carbon composite cerium oxide accounts for 1.5% to 5% or 0.5% to 3% of the mass of the doped / coated modified oxide positive electrode active material; (d4') The average thickness of the coating layer is 15nm to 40nm; (d5') ​​At least a portion of the coating layer has a thickness of 15nm to 40nm.

13. The solid-state battery according to any one of claims 1 to 12, characterized in that, The carbon composite oxygen-absorbing material satisfies one or more of the following characteristics: (e1) The carbon conductive material includes one or more of carbon nanofibers, carbon nanotubes, graphite, carbon black, carbon dots, graphene, Ketjen black and fullerene. (e2) The carbon conductive material is nanoparticles, and optionally, the average particle size of the carbon conductive material is 5 nm to 0.21 μm; Average particle size refers to the average of the maximum particle size of all particles; maximum particle size refers to the maximum diameter among the diameters of the particles in all directions. (e3) The maximum particle size of the carbon conductive material is less than or equal to 0.5 μm, and can be selected as 1 nm to 0.5 μm; (e4) The oxygen-absorbing material is nanoparticles, and optionally, the average particle size of the oxygen-absorbing material is 8nm to 50nm. (e5) The maximum particle size of the oxygen-absorbing substance is less than or equal to 200 nm, and can be selected as 1 nm to 200 nm; (e6) The oxygen-absorbing material includes nano-cerium oxide, wherein the average particle size of the nano-cerium oxide is 10 nm to 50 nm. (e7) The oxygen-absorbing material includes nano-cerium oxide, wherein the maximum particle size of the nano-cerium oxide is less than or equal to 200 nm, and may be selected from 1 nm to 200 nm.

14. The solid-state battery of claim 13, wherein, The carbon composite oxygen-absorbing material satisfies one or more of the following characteristics: (e1') The carbon conductive material includes vapor-grown carbon fibers; (e2') The average particle size of the carbon conductive material is 30 nm to 0.1 μm; (e3') The maximum particle size of the carbon conductive material is 8 nm to 0.5 μm, and can be selected as 50 nm to 0.3 μm; (e4') The average particle size of the oxygen-absorbing substance is 10 nm to 20 nm; (e5') The maximum particle size of the oxygen-absorbing substance is 5nm to 100nm; (e6') The oxygen-absorbing material includes nano-cerium oxide, wherein the average particle size of the nano-cerium oxide is 10nm to 20nm; (e7') The oxygen-absorbing material includes nano-cerium oxide, and the maximum particle size of the nano-cerium oxide is 5nm to 100nm.

15. The solid-state battery of any one of claims 1-14, wherein, The doped oxide-type positive electrode active material has a layered crystal structure.

16. The solid-state battery of any one of claims 1-15, wherein, The positive electrode active body comprises a lithium transition metal oxide, and the doped oxide-type positive electrode active material is at least a portion of the lithium transition metal oxide; the positive electrode active body satisfies one or more of the following characteristics: (f1) The lithium transition metal oxide includes lithium nickel-based oxide, which includes Li, non-lithium metal elements and O, and the non-lithium metal elements include Ni. (f2) The lithium transition metal oxide has a layered crystal structure; (f3) The lithium transition metal oxide accounts for 95% to 100% of the mass of the positive electrode active body.

17. The solid-state battery of claim 16, wherein, The lithium transition metal oxide includes lithium nickel-based oxides; The positive electrode active body satisfies one or more of the following characteristics: (i1) The atomic molar ratio of Ni to non-lithium metal elements in the lithium nickel-based oxide is q1, where 0.8 ≤ q1 ≤ 0.95; (i2) The lithium nickel-based oxide contains Ni and Li elements in an atomic molar ratio of q2:x2, wherein 0.8≤q2≤0.95 and 0.6≤x2≤1.2; (i3) The lithium nickel-based oxide contains Ni and O elements in an atomic molar ratio of q3:x3, wherein 0.8≤q3≤0.95 and 1.6≤x3≤2.2; (i4) The lithium nickel-based oxide contains Co, and the atomic molar ratio of Co to the non-lithium metal element in the lithium nickel-based oxide is q4, wherein 0.02≤q4≤0.15, and optionally 0.05≤q4≤0.15; (i5) The lithium nickel-based oxide contains Mn element, and the atomic molar ratio of Mn element to non-lithium metal element in the lithium nickel-based oxide is q5, wherein 0.02≤q5≤0.15, and optionally 0.05≤q5≤0.15; (i6) The lithium nickel-based oxide has a layered crystal structure; (i7) The lithium nickel-based oxide accounts for 80% to 100% of the mass of the lithium transition metal oxide; (i8) The lithium nickel-based oxide accounts for 80% to 100% of the mass of the positive electrode active body.

18. The solid-state battery of claim 17, wherein, The positive electrode active body satisfies one or more of the following characteristics: (j1)0.81≤q1≤0.93; (j2)0.81≤q2≤0.93; (j3)0.8≤x2≤1.1; (j4)0.81≤q3≤0.93; (j5)1.8≤x3≤2.06; (j6) The lithium nickel-based oxide contains Co, where 0.08 ≤ q4 ≤ 0.1; (j7) The lithium nickel-based oxide contains Mn element, 0.08≤q5≤0.1; (j8) The lithium nickel-based oxide accounts for 90% to 100% of the mass of the lithium transition metal oxide; (j9) The lithium nickel-based oxide accounts for 90% to 100% of the mass of the positive electrode active body; (j10) The lithium transition metal oxide includes lithium nickel cobalt manganese-based oxides; optionally, in the lithium nickel cobalt manganese-based oxide, the ratio of the sum of the atomic molar ratios of nickel, cobalt, and manganese to the sum of the atomic molar ratios of non-lithium metal elements is denoted as R. NCM R NCM The value is 0.9 to 1; further optionally, R NCM It ranges from 0.96 to 1.

19. The solid-state battery of any one of claims 1-18, wherein, The sulfide solid electrolyte includes one or more of LGPS-type sulfide electrolytes, binary sulfide electrolytes, and ternary sulfide electrolytes; The binary sulfide electrolyte includes one or more of the following: Li2S-GeS2 binary sulfide, Li2S-P2S5 binary sulfide, Li2S-SiS2 binary sulfide, and Li2S-B2S3 binary sulfide. The ternary sulfide electrolyte includes silver sulfide-germanium sulfide electrolyte and Li2S-M. 5 S2-P2S5 ternary sulfide electrolyte, lithium germanium phosphorus sulfide electrolyte, Li2S-P2S5-M 6 S-ternary sulfide electrolyte, Li2S-P2S5-M 6 Cl is one or more of a ternary sulfide electrolyte and a thio-LISICON type sulfide electrolyte; M 5 Includes one or more elements from Si, Ge, Sn, and Al; M 6 It includes one or more elements selected from Ge, Al, Sn, Pb, Sb, Si, and As.

20. The solid-state battery of any one of claims 1-19, wherein, The positive electrode active layer satisfies one or more of the following characteristics: (g1) The doped / coated modified oxide cathode active material accounts for 80% to 100% of the mass of the cathode active material; (g2) The mass percentage of the doped / coated modified oxide cathode active material in the cathode active layer is 70% to 95%; (g3) The sulfide solid electrolyte in the positive electrode active layer has a mass percentage content of 5% to 30%; (g4) The sulfide solid electrolyte accounts for 80% to 100% of the mass of the positive electrode electrolyte material.

21. The solid-state battery of claim 20, wherein, The positive electrode active layer satisfies one or more of the following characteristics: (g1') The doped / coated modified oxide cathode active material accounts for 90% to 100% of the mass of the cathode active material; (g2') The mass percentage of the doped / coated modified oxide cathode active material in the cathode active layer is 75% to 90%; (g3') The sulfide solid electrolyte in the positive electrode active layer has a mass percentage content of 10% to 30%; (g4') The sulfide solid electrolyte accounts for 90% to 100% of the mass of the positive electrode electrolyte material.

22. The solid-state battery of any one of claims 1-21, wherein, It meets one or more of the following characteristics: (h1) The solid-state battery is an all-solid-state battery; (h2) The solid-state battery is a lithium-ion secondary battery, which can be selected as an all-solid-state lithium-ion secondary battery.

23. A doped / coated modified oxide-based positive electrode active material, characterized in that, It includes the features of the doped / coated modified oxide-based positive electrode active material in the solid-state battery according to any one of claims 1 to 22.

24. A positive electrode sheet characterized by comprising: It includes a positive electrode active layer, wherein the positive electrode active layer comprises the features of the positive electrode active layer in the solid-state battery according to any one of claims 1 to 22.

25. A method of making a solid state battery, characterized by, The process includes the following steps: stacking the positive electrode, solid electrolyte material layer, and negative electrode in sequence, pressing them together, and preparing a solid-state battery. The positive electrode includes a positive active layer, which comprises a positive active material and a positive electrolyte material. The positive electrolyte material includes a sulfide solid electrolyte. The positive active material includes a doped / coated modified oxide-based positive active material, which comprises a positive active body and a coating layer located on at least a portion of the surface of the positive active body. The positive active body includes a doped oxide-based positive active material, which includes a doping element. The coating layer includes a carbon composite oxygen-absorbing material, which is a composite material based on a carbon conductive material and an oxygen-absorbing material. The oxygen-absorbing material includes an oxide-type oxygen-absorbing material. The solid electrolyte raw material layer comprises a solid electrolyte material.

26. The method of producing a solid state battery of claim 25, wherein, The positive electrode active layer includes the features of the positive electrode active layer in the solid-state battery according to any one of claims 1 to 22.

27. The method of producing a solid-state battery according to claim 25 or 26, characterized in that, The doped / coated modified oxide-based positive electrode active material is prepared by a method comprising the following steps: The oxide-based positive electrode active material raw material and the dopant source are ultrasonically dispersed, stirred, and dried in a first solvent to remove the first solvent, thereby obtaining a preliminary mixture; the preliminary mixture is then annealed in an oxygen-containing atmosphere to prepare the doped oxide-based positive electrode active material; wherein, the dopant source includes the dopant element; The doped oxide-type positive electrode active material is prepared by dry ball milling and mixing with the carbon composite oxygen-absorbing material.

28. The method of producing a solid state battery of claim 27, wherein, It meets one or more of the following characteristics: (k1) The first solvent includes one or more of ethanol, toluene, methanol and dimethyl ether; (k2) The rotation speed for the dry ball milling mixture is 300 rpm to 600 rpm; (k3) The ball milling time for the dry ball milling mixture is 12h to 36h; (k4) The annealing temperature is 400℃~800℃; (k5) The annealing process is performed for 2 hours to 12 hours; (k6) The carbon composite oxygen-absorbing material is prepared by a method comprising the following steps: mixing carbon conductive material raw material and oxygen-absorbing material raw material in a second solvent, performing liquid-phase ball milling, and drying to remove the second solvent, thereby preparing the carbon composite oxygen-absorbing material; optionally, the second solvent includes one or more of ethanol, toluene, methanol, and dimethyl ether; optionally, the rotation speed of the liquid-phase ball milling is 300 rpm to 600 rpm, and the ball milling time is 12 h to 36 h; (k7) The electronic conductivity of the carbon composite oxygen-absorbing material at 25℃ is ≥5mS / cm; (k8) The positive electrode sheet is prepared by a method comprising the following steps: mixing a positive electrode material composition comprising the doped / coated modified oxide positive electrode active material and the sulfide solid electrolyte, and forming a film under solvent-free conditions; wherein, the positive electrode material composition may optionally include one or more of a binder and a conductive agent; (k9) Prepare the solid-state battery as described in any one of claims 1 to 21.

29. An electrical device, comprising: It includes at least one of the following: the solid-state battery according to any one of claims 1 to 22, the doped / coated modified oxide positive electrode active material according to claim 23, the positive electrode sheet according to claim 24, and the solid-state battery prepared by the method of preparing the solid-state battery according to any one of claims 25 to 28.

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