High-load solid positive electrode and preparation method and application thereof

Abstract

The invention relates to the technical field of battery positive electrode materials, in particular to a high-load solid-state positive electrode and a preparation method and application thereof, and the high-load solid-state positive electrode comprises a current collector and a composite positive electrode layer located on one side of the current collector; the composite positive electrode layer comprises the following raw materials in percentage by mass: 0.1 wt%-10 wt% of nano metal oxide, 65 wt%-95 wt% of a positive electrode active material and 4 wt%-35 wt% of inorganic solid electrolyte. A continuous electron conduction path can be formed between the positive electrode active materials by utilizing the nano metal oxide with good electron conductivity, and the side reaction degree of the nano metal oxide to the inorganic solid electrolyte is relatively low, so that the high-load solid-state positive electrode has an electron transmission seepage network and a low-tortuosity ion transmission network; and the oxygenolysis of sulfide in the positive electrode is effectively inhibited, so that the excellent rate capability and long cycle stability of the battery are realized.

Description

Technical Field

[0001] This invention relates to the field of battery cathode material technology, and in particular to a high-load solid cathode, its preparation method and application. Background Technology

[0002] Solid-state batteries (SSBs) are considered a next-generation battery technology with high energy density and safety, suitable for electric vehicles. Currently, these batteries use lithium metal as the negative electrode, high-load, high-voltage ternary nickel-cobalt-manganese material as the positive electrode, and a sulfide electrolyte with high ionic conductivity and mechanical ductility as the electrolyte layer, achieving both high energy density and high safety.

[0003] However, the poor ion / electron transport capabilities of existing solid-state batteries limit the application of high-load, high-area-capacity ternary cathode materials in solid-state lithium batteries; furthermore, with increasing loading, Li... + As the electron transport distance increases, the charge transfer kinetics deteriorate, resulting in a reduction in the capacity of the active material and a lower battery power density.

[0004] To solve the problem of Li in high-load solid cathodes + The problem of poor transport properties is usually addressed by optimizing the interfacial contact between the electrolyte material and the positive electrode active material, such as by mixing materials using a blade grinder to achieve a uniform coating of the electrolyte with the active material. However, the battery power density is also affected by Li. + Lithium-ion conduction networks with low tortuosity are limited by transport networks and tortuosity. While 3D printing or cryogenic casting techniques can achieve low-torque lithium-ion conduction networks in oxide solid electrolytes, these methods are difficult to scale up. Furthermore, besides optimizing Li... + In addition to electron transport, electron transport within the high-load positive electrode is also crucial. Introducing conductive carbon can build a good electron transport network; however, conductive carbon can exacerbate the degradation of sulfide electrolytes, further deteriorate the interface, and lead to battery performance degradation.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a high-load solid cathode, its preparation method and application, aiming to solve the problem of Li in existing solid cathodes. + The problem of poor transmission and difficulty in achieving low-torsion lithium-ion conduction networks.

[0007] The technical solution of the present invention is as follows: A high-load solid positive electrode includes a current collector and a composite positive electrode layer located on one side of the current collector; the raw material composition of the composite positive electrode layer, by mass percentage, includes 0.1wt%-10wt% nano-metal oxide, 65wt%-95wt% positive electrode active material, and 4wt%-35wt% inorganic solid electrolyte.

[0008] The high-load solid cathode wherein the particle size of the nano-metal oxide is 10nm-100nm.

[0009] The high-load solid cathode, wherein the particle size of the cathode active material is 2μm-40μm.

[0010] The high-load solid cathode, wherein the D50 particle size of the inorganic solid electrolyte is 10μm-40μm.

[0011] The high-load solid-state cathode, wherein the nano-metal oxide comprises one or more of the following: modified or unmodified Li2O, Na2O, K2O, MgO, CaO, BaO, Fe2O3, Fe3O4, CuO, Cu2O, MnO2, NiO, CoO, ZnO, TiO2, Cr2O3, Ag2O, Al2O, PbO, SnO2, and In2O3.

[0012] The high-load solid cathode, wherein the cathode active material includes one or more of lithium cobalt oxide, lithium orthogonal manganese oxide, lithium nickel oxide, lithium vanadium oxide, ternary lithium nickel cobalt manganese oxide, spinel lithium manganese oxide, lithium nickel manganese oxide, lithium iron phosphate, and ternary lithium nickel cobalt manganese oxide coated with lithium niobate.

[0013] The high-load solid cathode, wherein the inorganic solid electrolyte comprises one or more of binary sulfide electrolytes, sulfogermanium sulfide electrolytes, and halide electrolytes; The binary sulfide electrolyte is selected from 80Li2S-20P2S5 and Li7P3S. 11 One or more of Li6PS5Cl, 70Li2S-30P2S5; the silver-germanium sulfide electrolyte is selected from Li 5.5 PS 4.5 Cl 1.5 Li7P2S8I, Li6PS5Cl, Li 6.6 P 0.4 Ge 0.6 S5I, Li7P2S8Br 0.5 I, 0.5Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 Li11 Si2PS 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of the following; the halide electrolyte is selected from Li3InCl6, Li2ZrCl6, Li2Zr x Fe 1-x One or more of Cl6 and Li3ScCl6.

[0014] The high-load solid positive electrode wherein the current collector is made of at least one of aluminum, boron, gold, silver, platinum, carbon, iron, titanium, nickel, and stainless steel.

[0015] A method for preparing a high-load solid-state cathode includes the following steps: A mixture is obtained by mixing nano-metal oxides, positive electrode active materials, and inorganic solid electrolytes; Add milling beads to the mixture, and then mill it in a vibrating ball mill to obtain composite cathode powder; The composite cathode powder is placed on one side of the current collector and compacted to obtain a high-load solid cathode.

[0016] Application of a high-load solid-state cathode in all-solid-state batteries.

[0017] Beneficial Effects: This invention provides a high-load solid-state cathode, its preparation method, and its application. The high-load solid-state cathode includes a current collector and a composite cathode layer located on one side of the current collector. The raw material composition of the composite cathode layer, by mass percentage, includes 0.1wt%-10wt% nano-metal oxide, 65wt%-95wt% cathode active material, and 4wt%-35wt% inorganic solid electrolyte. This invention prepares a high-load solid-state cathode based on nano-metal oxide as a conductive additive, along with cathode active material and inorganic solid electrolyte. The nano-metal oxide, possessing good electronic conductivity, enables the formation of continuous electronic conduction pathways between cathode active materials. Furthermore, the nano-metal oxide exhibits a low degree of side reaction with the inorganic solid electrolyte, resulting in a high-load solid-state cathode with an electron transport percolation network and a low-torsion ion transport network. It also effectively suppresses the oxidative decomposition of sulfides in the cathode, thereby enabling the battery to achieve excellent rate performance and long-cycle stability. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the process flow for a high-load solid-state cathode preparation method according to the present invention; Figure 2 A schematic diagram of the electrode structure of the high-load solid positive electrode prepared in Example 1; Figure 3 The graph shows the rate performance test data of the all-solid-state battery assembled with the high-load solid cathode prepared in Example 1 at 60°C. Figure 4 The cycling performance of the all-solid-state battery assembled with a high-load solid cathode prepared in Example 1 at 30°C and 2C current density is shown in the figure. Figure 5 The cycling performance of the all-solid-state battery assembled with a high-load solid cathode prepared in Example 1 at 30°C and 1C current density is shown in the graph. Figure 6 The graph shows the cycling performance of the all-solid-state battery assembled with a high-load solid cathode prepared in Example 1 at 60°C and a current density of 0.5C. Detailed Implementation

[0019] This invention provides a high-load solid-state cathode, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0021] This invention proposes a high-load solid positive electrode, comprising a current collector and a composite positive electrode layer located on one side of the current collector; the raw material composition of the composite positive electrode layer, by mass percentage, includes 0.1wt%-10wt% nano-metal oxide, 65wt%-95wt% positive electrode active material, and 4wt%-35wt% inorganic solid electrolyte.

[0022] In this embodiment, a high-load solid cathode is prepared by using nano-metal oxides as conductive additives in conjunction with positive electrode active materials and inorganic solid electrolytes. The nano-metal oxides, which have good electronic conductivity, can form a continuous electronic conduction pathway between positive electrode active materials. Furthermore, the nano-metal oxides have a low degree of side reaction with the inorganic solid electrolyte, resulting in a high-load solid cathode with an electron transport percolation network and a low-torsion ion transport network. This effectively suppresses the oxidative decomposition of sulfides in the cathode, thereby enabling the battery to achieve excellent rate performance and long-cycle stability.

[0023] Specifically, in the composite cathode layer of the present invention, the nano-metal oxide possesses excellent electronic conductivity, enabling the formation of continuous electronic conduction pathways between the cathode active materials. Furthermore, the nano-metal oxide exhibits low side reaction intensity with the inorganic solid electrolyte. Simultaneously, the high-load solid cathode, based on the nano-metal oxide as a conductive additive, possesses a low-torsion ion-conducting network, allowing for rapid ion transport between the current collector and electrolyte layers. This results in an all-solid-state battery with excellent power density. The all-solid-state battery assembled using this high-load solid cathode exhibits high power density, high energy density, and high energy density retention. Moreover, by controlling the composition of the composite cathode layer within the aforementioned mass percentages, 0.1wt%-10wt% of nano-metal oxide does not affect ion transport in the composite cathode layer while achieving good electron transport; 4wt%-35wt% of inorganic solid electrolyte can construct an excellent ion transport network in the cathode; and 65wt%-95wt% of cathode active material can achieve high energy density.

[0024] In some embodiments, the particle size of the nano-metal oxide is 10 nm to 100 nm. Nano-sized particles can more thoroughly break down the material during ball milling, resulting in a composite cathode layer with good interfacial contact after ball milling.

[0025] In a preferred embodiment, the particle size of the nano-metal oxide is 50nm-100nm.

[0026] In some embodiments, the particle size of the positive electrode active material is 2μm-40μm. During ball milling, the micron-sized positive electrode active material collides with the nano-metal oxide particles and the inorganic solid electrolyte material. The electrolyte material broken up by the nano-metal oxide particles can be uniformly coated on the positive electrode active material, thereby achieving better interfacial contact between the materials.

[0027] In a preferred embodiment, the particle size of the positive electrode active material is 2μm-20μm.

[0028] In some embodiments, the D50 particle size of the inorganic solid electrolyte is 10μm-40μm. Large-particle inorganic solid electrolytes are typically secondary particles composed of multiple smaller particles. During ball milling, some of these secondary particles are broken down, achieving excellent interfacial contact with the positive electrode active material during collisions. The unbroken secondary particles can then facilitate rapid lithium-ion transport between the current collector and electrolyte layers within the composite positive electrode layer, constructing a low-torsion lithium-ion transport network.

[0029] In a preferred embodiment, the D50 particle size of the inorganic solid electrolyte is 20μm-30μm.

[0030] In some embodiments, the nano-metal oxide includes one or more of the following: modified or unmodified Li₂O, Na₂O, K₂O, MgO, CaO, BaO, Fe₂O₃, Fe₃O₄, CuO, Cu₂O, MnO₂, NiO, CoO, ZnO, TiO₂, Cr₂O₃, Ag₂O, Al₂O, PbO, SnO₂, and In₂O₃. These nano-metal oxides possess high hardness, allowing for sufficient collision with other materials during ball milling, resulting in better interfacial contact. Furthermore, these nano-metal oxides, whether intrinsically or after modification, exhibit high electronic conductivity, enabling the construction of an effective electron transport network in the positive electrode.

[0031] In a preferred embodiment, the nano-metal oxide is modified or unmodified high electronic conductivity nano-In₂O₃, wherein In₂O₃ has a conductivity of 10⁻⁶ ppm at room temperature. -4 -10 -2 S cm -1 Its high electronic conductivity, after modification, further enhances it to 10. 3 -10 4 Scm -1 Its high conductivity allows for more efficient electron transport.

[0032] In some embodiments, the positive electrode active material includes lithium cobalt oxide (LiCoO2), lithium orthogonal manganese oxide (LiMnO2), lithium nickel oxide (LiNiO2), lithium vanadium oxide (LiVO2), and ternary lithium nickel cobalt manganese oxide (LiNiO2). 0.8 CO 0.1 Mn 0.1 O2), lithium spinel manganese oxide (LiMn2O4), lithium nickel manganese oxide (Li(Ni 0.5 Mn 1.5 Lithium iron phosphate (LiFePO4), lithium niobate-coated ternary lithium nickel cobalt manganese oxide (LiNiO4), and lithium iron phosphate (LiFePO4) are also mentioned. 0.8 CO 0.1 Mn 0.1 One or more of the following (O2).

[0033] In some embodiments, the inorganic solid electrolyte includes one or more of binary sulfide electrolytes, sulfogermanium sulfide electrolytes, and halide electrolytes. The binary sulfide electrolyte is selected from 80Li2S-20P2S5 and Li7P3S. 11 One or more of Li6PS5Cl, 70Li2S-30P2S5; the silver-germanium sulfide electrolyte is selected from Li 5.5 PS 4.5 Cl 1.5 Li7P2S8I, Li6PS5Cl, Li 6.6 P0.4 Ge 0.6 S5I, Li7P2S8Br 0.5 I, 0.5Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 Li 11 Si2PS 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of the following; the halide electrolyte is selected from Li3InCl6, Li2ZrCl6, Li2Zr x Fe 1-x One or more of Cl6 and Li3ScCl6. Sulfide and halide electrolytes have excellent machinability, making them suitable for the preparation of composite solid cathodes and achieving excellent interfacial contact.

[0034] In some embodiments, the current collector is made of at least one of aluminum, boron, gold, silver, platinum, carbon, iron, titanium, nickel, and stainless steel; current collectors made of the above materials have excellent electrical conductivity.

[0035] In some embodiments, the thickness of the composite positive electrode layer is 100μm-150μm; the thickness of the current collector is 6μm-12μm.

[0036] In a preferred embodiment, the thickness of the composite positive electrode layer is 130 μm; the thickness of the current collector is 10 μm.

[0037] In addition, such as Figure 1 The present invention also provides a method for preparing a high-load solid-state cathode, comprising the following steps: Step S10: Mix the nano-metal oxide, the positive electrode active material, and the inorganic solid electrolyte to obtain a mixture; Step S20: Add milling beads to the mixture and mill it in a vibrating ball mill to obtain composite cathode powder; Step S30: Place the composite cathode powder on one side of the current collector and compact it to obtain a high-load solid cathode.

[0038] In this embodiment, a high-load solid cathode is prepared by using a ball milling method with nano-metal oxides as conductive additives, positive electrode active materials, and inorganic solid electrolytes. The nano-metal oxides, which have good electronic conductivity, can form a continuous electronic conduction pathway between the positive electrode active materials. Furthermore, the nano-metal oxides have a low degree of side reaction with the inorganic solid electrolyte, resulting in a high-load solid cathode with an electron transport percolation network and a low-torsion ion transport network. This effectively suppresses the oxidative decomposition of sulfides in the cathode, thereby enabling the battery to achieve excellent rate performance and long-cycle stability.

[0039] In some embodiments, in step S10, the particle size of the nano-metal oxide is 10 nm-1 μm; the particle size of the positive electrode active material is 2 μm-40 μm; and the D50 particle size of the inorganic solid electrolyte is 10 μm-40 μm.

[0040] In some embodiments, the mass ratio of the mixture to the grinding beads is 1:(3-10). This mass ratio ensures that the cathode material is not damaged while allowing for thorough mixing of different materials. Preferably, the grinding beads are zirconium beads.

[0041] In some embodiments, in step S20, the ball milling time is 10-30 minutes.

[0042] Specifically, nano-metal oxides, positive electrode active materials, and inorganic solid electrolytes are placed in a grinding tube according to the above mass percentages and ball-milled for 10-30 minutes using a vibrating ball mill; then, a certain proportion of zirconium beads are added to the grinding tube and ball-milled again for 10-30 minutes using a vibrating ball mill; finally, the zirconium beads are removed to obtain composite positive electrode powder, a certain amount of powder is placed on a current collector, dispersed evenly, and compacted to obtain a high-load solid positive electrode.

[0043] In some embodiments, in step S30, the compaction pressure is 2 to 4 tons, and the pressure holding time is 2 to 5 minutes.

[0044] In a preferred embodiment, in step S30, the compaction pressure is 3 tons and the pressure holding time is 3 minutes.

[0045] In addition, the present invention also provides an application of a high-load solid-state cathode in an all-solid-state battery.

[0046] In this embodiment, the all-solid-state battery assembled based on the high-load solid-state cathode has high power density, high energy density, and high energy density retention.

[0047] In some embodiments, the all-solid-state battery includes the high-load solid positive electrode, the negative electrode, and the solid electrolyte; preferably, the negative electrode is one of a lithium metal negative electrode or an alloy negative electrode.

[0048] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0049] Example 1 This embodiment provides a high-load solid-state cathode, the specific preparation process of which is as follows: S1: LiNi coated with nano-In2O3 and lithium niobate with a D50 of 2μm 0.8 CO 0.1 Mn 0.1 O2 and Li with D50=20μm 5.5 PS 4.5 Cl 1.5 Electrolyte powder was placed in a grinding tube at a mass ratio of 3:70:27 and ball-milled for 15 minutes using a vibrating ball mill to obtain a mixture. S2: Add 3mm zirconium beads, which are 5 times the mass of the mixture, to the grinding tube in step S1, and then ball mill again for 15 minutes using a vibrating ball mill. S3: After removing the zirconium beads in step S2, composite cathode powder is obtained. 30mg of composite cathode powder is placed on carbon-coated aluminum foil, dispersed evenly, and compacted under 3 tons of pressure for 3 minutes to obtain a high-load solid cathode.

[0050] A schematic diagram of the electrode structure of the high-load solid positive electrode prepared in this embodiment is shown below. Figure 2 As shown, the electrolyte particles of different sizes construct a lithium-ion transport network with low tortuosity. In addition, the nano-metal oxide realizes the electron percolation network in the positive electrode.

[0051] The high-load solid-state cathode and lithium-indium alloy prepared in this embodiment were used as the anode and sulfide electrolyte layer to assemble an all-solid-state battery. Rate performance was tested at 60°C, and the results are as follows: Figure 3 As shown, from Figure 3 The battery is shown to be at 17.86 mg / cm². -2 Under high load, the 2C rate still maintains 130mAh g. -1 The battery exhibits a high specific capacity with no significant capacity decay. Therefore, batteries assembled using high-load solid-state cathodes possess excellent power density.

[0052] The high-load solid-state cathode prepared in this embodiment, along with lithium-indium alloy as the anode and a sulfide electrolyte layer, were used to assemble an all-solid-state battery. Low-load cycle performance tests were conducted to observe the excellent electrochemical stability of the In₂O₃ metal oxide on the electrolyte powder. The results are as follows: Figure 4 As shown, from Figure 4 As can be seen, the battery still retains 90% of its capacity after 1500 cycles at 30℃ and 2C current density, demonstrating that In2O3 has a low degree of electrolyte side reaction and a long battery life.

[0053] The high-load solid-state cathode, lithium metal anode, and sulfide electrolyte layer prepared in this embodiment were assembled into an all-solid-state battery, and their cycling performance under high load was tested. The role of the low-torsivity lithium-ion transport network assisted by In2O3 metal oxide in the long-term cycling of the battery was observed. The results are as follows: Figure 5 As shown, from Figure 5 As can be seen, after 1000 cycles at 30℃ and 1C current density, the all-solid-state battery still retains 80.4% of its specific capacity, which shows that the low tortuosity lithium-ion transport network built with the help of In2O3 can help the battery cycle stably.

[0054] The high-load solid-state cathode, lithium metal anode, and sulfide electrolyte layer prepared in this embodiment were assembled into an all-solid-state battery, and their cycling performance under ultra-high load was tested. This further highlights the role of the low-torsivity lithium-ion transport network assisted by In2O3 metal oxide in battery cycling. The results are as follows: Figure 6 As shown, from Figure 6 It can be seen from this that the battery is at 42.56 mg cm⁻¹ -2 Under ultra-high load, it can cycle stably at 60℃ and 0.5C current density, highlighting the advantage of the prepared cathode in stable cycling under ultra-high load.

[0055] Example 2 This embodiment provides a high-load solid-state cathode, the specific preparation process of which is as follows: S1: Coating LiCoO2 with nano-In2O3 and lithium niobate with a D50 of 2μm and Li with a D50 of 20μm 5.5 PS 4.5 Cl 1.5 Electrolyte powder was placed in a grinding tube at a mass ratio of 3:70:27 and ball-milled for 15 minutes using a vibrating ball mill to obtain a mixture. S2: Add 3mm zirconium beads, which are 5 times the mass of the mixture, to the grinding tube in step S1, and then ball mill again for 15 minutes using a vibrating ball mill. S3: After removing the zirconium beads in step S2, composite cathode powder is obtained. 30mg of composite cathode powder is placed on carbon-coated aluminum foil, dispersed evenly, and compacted under 3 tons of pressure for 3 minutes to obtain a high-load solid cathode.

[0056] Example 3 This embodiment provides a high-load solid-state cathode, the specific preparation process of which is as follows: S1: LiNi coated with oxygen-deficient nano-In2O3 and lithium niobate with a D50 of 2μm 0.8 CO 0.1 Mn 0.1 O2 and Li with D50=20μm 5.5 PS 4.5 Cl 1.5 Electrolyte powder was placed in a grinding tube at a mass ratio of 3:70:27 and ball-milled for 15 minutes using a vibrating ball mill to obtain a mixture. S2: Add 3mm zirconium beads, which are 5 times the mass of the mixture, to the grinding tube in step S1, and then ball mill again for 15 minutes using a vibrating ball mill. S3: After removing the zirconium beads in step S2, composite cathode powder is obtained. 30mg of composite cathode powder is placed on carbon-coated aluminum foil, dispersed evenly, and compacted under 3 tons of pressure for 3 minutes to obtain a high-load solid cathode.

[0057] Example 4 This embodiment provides a high-load solid-state cathode, the specific preparation process of which is as follows: S1: LiNi coated with nano-In2O3 and lithium niobate with a D50 of 2μm 0.8 CO 0.1 Mn 0.1 O2 and Li3InCl6 electrolyte powder with D50=20μm were placed in a grinding tube at a mass ratio of 3:70:27 and ball-milled for 15 minutes using a vibrating ball mill to obtain a mixture. S2: Add 3mm zirconium beads, which are 5 times the mass of the mixture, to the grinding tube in step S1, and then ball mill again for 15 minutes using a vibrating ball mill. S3: After removing the zirconium beads in step S2, composite cathode powder is obtained. 30mg of composite cathode powder is placed on carbon-coated aluminum foil, dispersed evenly, and compacted under 3 tons of pressure for 3 minutes to obtain a high-load solid cathode.

[0058] Example 5 This embodiment provides a high-load solid-state cathode, the specific preparation process of which is as follows: S1: LiNi coated with nano-In2O3 and lithium niobate with a D50 of 2μm 0.8 CO 0.1 Mn 0.1 O2 and Li with D50=20μm 5.5 PS 4.5 Cl 1.5Electrolyte powder was placed in a grinding tube at a mass ratio of 1:85:14 and ball-milled for 15 minutes using a vibrating ball mill to obtain a mixture. S2: Add 3mm zirconium beads, which are 5 times the mass of the mixture, to the grinding tube in step S1, and then ball mill again for 15 minutes using a vibrating ball mill. S3: After removing the zirconium beads in step S2, composite cathode powder is obtained. 30mg of composite cathode powder is placed on carbon-coated aluminum foil, dispersed evenly, and compacted under 3 tons of pressure for 3 minutes to obtain a high-load solid cathode.

[0059] In summary, this invention provides a high-load solid-state cathode, its preparation method, and its application. The high-load solid-state cathode includes a current collector and a composite cathode layer located on one side of the current collector. The raw material composition of the composite cathode layer, by mass percentage, includes 0.1wt%-10wt% nano-metal oxide, 65wt%-95wt% cathode active material, and 4wt%-35wt% inorganic solid electrolyte. This invention prepares a high-load solid-state cathode based on nano-metal oxide as a conductive additive, along with cathode active material and inorganic solid electrolyte. The nano-metal oxide, possessing good electronic conductivity, enables the formation of continuous electronic conduction pathways between cathode active materials. Furthermore, the nano-metal oxide exhibits a low degree of side reaction with the inorganic solid electrolyte, resulting in a high-load solid-state cathode with an electron transport percolation network and a low-torsion ion transport network. It also effectively suppresses the oxidative decomposition of sulfides in the cathode, thereby enabling the battery to achieve excellent rate performance and long-cycle stability.

[0060] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A high-load solid-state cathode, characterized in that, It includes a current collector and a composite positive electrode layer located on one side of the current collector; the raw material composition of the composite positive electrode layer, by mass percentage, includes 0.1wt%-10wt% nano-metal oxide, 65wt%-95wt% positive electrode active material, and 4wt%-35wt% inorganic solid electrolyte.

2. The high-load solid-state cathode according to claim 1, characterized in that, The particle size of the nano-metal oxide is 10nm-100nm.

3. The high-load solid-state cathode according to claim 1, characterized in that, The particle size of the positive electrode active material is 2μm-40μm.

4. The high-load solid-state cathode according to claim 1, characterized in that, The D50 particle size of the inorganic solid electrolyte is 10μm-40μm.

5. The high-load solid-state cathode according to claim 1, characterized in that, The nano-metal oxides include one or more of the following: modified or unmodified Li2O, Na2O, K2O, MgO, CaO, BaO, Fe2O3, Fe3O4, CuO, Cu2O, MnO2, NiO, CoO, ZnO, TiO2, Cr2O3, Ag2O, Al2O, PbO, SnO2, and In2O3.

6. The high-load solid-state cathode according to claim 1, characterized in that, The positive electrode active material includes one or more of lithium cobalt oxide, lithium orthogonal manganese oxide, lithium nickel oxide, lithium vanadium oxide, ternary lithium nickel cobalt manganese oxide, spinel manganese oxide, lithium nickel manganese oxide, lithium iron phosphate, and ternary lithium nickel cobalt manganese oxide coated with lithium niobate.

7. The high-load solid-state cathode according to claim 1, characterized in that, The inorganic solid electrolyte includes one or more of binary sulfide electrolytes, sulfide electrolytes of silver-germanium ore type, and halide electrolytes. The binary sulfide electrolyte is selected from 80Li2S-20P2S5 and Li7P3S. 11 One or more of Li6PS5Cl, 70Li2S-30P2S5; the silver-germanium sulfide electrolyte is selected from Li 5.5 PS 4.5 Cl 1.5 Li7P2S8I, Li6PS5Cl, Li 6.6 P 0.4 Ge 0.6 S5I, Li7P2S8Br 0.5 I, 0.5Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 Li 11 Si2PS 12 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 One or more of the following; the halide electrolyte is selected from Li3InCl6, Li2ZrCl6, Li2Zr x Fe 1-x One or more of Cl6 and Li3ScCl6.

8. The high-load solid-state cathode according to claim 1, characterized in that, The material of the current collector includes at least one of aluminum, boron, gold, silver, platinum, carbon, iron, titanium, nickel, and stainless steel.

9. A method for preparing a high-load solid-state cathode as described in any one of claims 1-8, characterized in that, Including the following steps: A mixture is obtained by mixing nano-metal oxides, positive electrode active materials, and inorganic solid electrolytes; Add milling beads to the mixture, and then mill it in a vibrating ball mill to obtain composite cathode powder; The composite cathode powder is placed on one side of the current collector and compacted to obtain a high-load solid cathode.

10. The application of a high-load solid-state cathode as described in any one of claims 1-8 in an all-solid-state battery.

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