A method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxides

Abstract

This invention discloses a method for manufacturing composite cathode particles coated with ceramic particles using nickel cobalt manganese oxide, comprising the following steps: Step 500: sintering multiple nickel cobalt manganese hydroxides to obtain multiple nickel cobalt manganese oxides; Step 510: mixing the multiple nickel cobalt manganese oxides, multiple lithium carbonates, and an LLZO precursor to form a precursor mixture; Step 520: sintering the precursor mixture; the sintering step is further subdivided into: Step 520-1: first heating in an atmospheric or oxygen-containing environment, the multiple lithium carbonates decompose into multiple lithium oxides; Step 520-2: then holding the temperature and introducing oxygen; the lithium oxides react with each of the nickel cobalt manganese oxides and the LLZO precursor to form multiple NCM particles with a rhombohedral crystal phase and multiple LLZO particles; Step 520-3: continuing to heat, causing the lattice within each of the NCM particles with a rhombohedral crystal phase to rearrange to form multiple composite cathode particles.

Description

Technical Field

[0001] This invention relates to the field of battery cathode technology, and in particular to a method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide. Background Technology

[0002] A battery is mainly formed by a positive electrode and a negative electrode placed in an electrolyte. The positive electrode is formed by mixing and dispersing numerous positive electrode conductive units (positive electrode materials, such as lithium cobalt oxide) in a slurry. To increase conductivity, multiple positive electrode particles are filled into the positive electrode slurry. The material of these positive electrode particles can be selected from NCM (lithium nickel cobalt manganese oxide) and mixtures containing NCM.

[0003] However, in conventional technologies, the interface of the cathode particles is prone to side reactions, leading to a decrease in the cathode's lifespan and low electronic conductivity, resulting in poor overall battery performance. Therefore, conventional technologies also coat the cathode particles with ceramic particles such as LLZO (lithium lanthanum zirconium oxide) to increase their conductivity for lithium ions. To further increase the conductivity of the slurry, carbon nanotubes and nanoscale amorphous carbon can also be added to coat the cathode particles.

[0004] In conventional technology, during the manufacture of NCM (lithium nickel cobalt manganese oxide), all precursors, including nickel cobalt manganese hydroxide, lithium carbonate, and LLZO precursor, are simultaneously placed into a sintering furnace for sintering. Ideally, the nickel cobalt manganese hydroxide should form nickel cobalt manganese oxide, and the lithium carbonate should form lithium oxide. However, this method of sintering all materials together at once causes the hydroxide ions of the nickel cobalt manganese hydroxide to chemically react with the lithium carbonate. Therefore, the lithium carbonate cannot completely react to form lithium oxide. Consequently, the final product contains NCM particles formed from nickel cobalt manganese hydroxide, nickel cobalt manganese oxide, lithium carbonate, lithium oxide, and other materials. The phase composition of these NCM particles is quite disordered, which not only affects the appearance of the finished product but also makes them unsuitable as battery materials.

[0005] Based on its long-standing experience with battery materials, the applicant of this case hopes to propose a novel design. The nickel-cobalt-manganese hydroxide is first sintered and dehydrated to obtain nickel-cobalt-manganese oxide, which is then mixed with other materials and sintered. The sintering temperature is divided into three stages of heating to obtain NCM particles with good lattice phase formation. Summary of the Invention

[0006] Therefore, the purpose of this case is to solve the problems of the aforementioned prior art. This case proposes a method for manufacturing composite cathode particles coated with ceramic particles using nickel cobalt manganese oxide. The method involves first dehydrating the nickel cobalt manganese hydroxide to form nickel cobalt manganese oxide. Therefore, during subsequent sintering, the lithium carbonate does not readily react with the hydroxide ions of the original nickel cobalt manganese hydroxide, allowing the lithium carbonate to react completely to form lithium oxide. The lithium oxide then reacts with the nickel cobalt manganese oxide to form NCM particles with a rhombohedral crystal phase. Through high temperature, composite cathode particles with the correct crystal phase are then formed. This method of first dehydrating the nickel cobalt manganese hydroxide to form nickel cobalt manganese oxide ensures that the final product has the correct crystal phase and a well-ordered crystal lattice, making it more suitable for battery materials.

[0007] To achieve the above objectives, this invention proposes a method for manufacturing composite cathode particles coated with ceramic particles using nickel cobalt manganese oxides. These composite cathode particles are used as cathodes in general solid-state or near-solid-state batteries. The method includes the following steps: Step 500: Multiple nickel cobalt manganese hydroxides (NCM-OH) are placed in a first sintering furnace and sintered and dehydrated under a low-oxygen environment to obtain multiple nickel cobalt manganese oxides (NCM-O). These multiple nickel cobalt manganese oxides are precursors for forming NCM (lithium nickel cobalt manganese oxide); Step 510: The multiple nickel cobalt manganese oxides, multiple lithium carbonates, and the LLZO precursor are placed in a mixer and mixed to form a precursor mixture; wherein the nickel cobalt manganese oxides are granular particles formed from multiple particles. The material, the nickel-cobalt-manganese oxide particles, have multiple pores or depressions on their surface; Step 520: The precursor mixture is placed in a second sintering furnace for sintering; the sintering steps are subdivided as follows: Step 520-1: The temperature is first raised to 650℃~900℃ in an atmospheric or oxygen-containing environment, so that the multiple lithium carbonates in the precursor mixture melt into liquid, and the molten multiple lithium carbonates enter the multiple pores or depressions of the nickel-cobalt-manganese oxide. At the same time, the multiple lithium carbonates decompose into multiple lithium oxides (Li2O). The sintering time of this step is between 1 hour and 10 hours; Step 520-2: Then, the temperature is held at a set temperature and oxygen is introduced; wherein the set temperature is between 650℃ and 900℃; the holding time is between 1 hour and 10 hours. Hours to 5 hours; during this time, a portion of the lithium oxide in the precursor mixture will initially react with each of the nickel, cobalt, and manganese oxides to form multiple rhombohedral NCM particles. In this rhombohedral phase, the lithium ions in the lithium oxide and the nickel, cobalt, and manganese ions in the nickel, cobalt, and manganese oxides are arranged in an unstratified, i.e., mixed state. At the same time, another portion of the lithium oxide will also react with the LLZO precursor to form multiple LLZO particles. These multiple LLZO particles coat the outer surface of each rhombohedral NCM particle. Step 520-3: Then, the temperature is further increased under an oxygen atmosphere, causing the lattice within the multiple rhombohedral NCM particles to rearrange, thus allowing the lithium ions to react with the nickel, cobalt, and manganese ions. The arrangement of particles is completely layered to form NCM particles with a completely layered structure, thus forming multiple composite cathode particles; wherein the heating temperature in this step is 900℃~1000℃, and the sintering time is between 1 hour and 5 hours; Step 520-4: Then the multiple composite cathode particles are taken out and cooled to obtain sintered powder formed by the multiple composite cathode particles; wherein the melting point of lithium carbonate is lower than that of nickel cobalt manganese oxide and the LLZO precursor, so it will melt first and enter the multiple pores or depressions of nickel cobalt manganese oxide to react with nickel cobalt manganese oxide; the multiple NCM particles with rhombohedral crystal phase and corresponding LLZO particles are then rearranged at high temperature to generate multiple corresponding composite cathode particles.

[0008] The features and advantages of this work will be further explained in the following description; please refer to the accompanying drawings while reading. Attached Figure Description

[0009] Figure 1 This diagram shows the manufacturing steps of the composite cathode particles in this case.

[0010] Figure 2 This diagram shows the manufacturing process of the composite cathode particles in this case.

[0011] Figure 3 This diagram shows the structure of the composite cathode particles in this case.

[0012] Figure 4 This shows a cross-sectional view of the composite cathode particles in this case.

[0013] Figure 5 This example demonstrates the application of this case.

[0014] Figure 6 This diagram shows the structure of the carbon-coated cathode particles in this case.

[0015] Figure 7 This diagram shows the structure of the nickel-cobalt-manganese oxide in this case.

[0016] Figure 8 This diagram shows the crystal lattice of the NCM particles with rhombohedral phase in this case.

[0017] Figure 9 This diagram shows a lattice schematic of the NCM particles with a fully layered structure in this case.

[0018] Figure 10 This shows a detailed flowchart of step 520 in this case.

[0019] The components include: a positive electrode substrate 10, a positive electrode slurry layer 12, a positive electrode slurry 14, nickel-cobalt-manganese oxide 20, pores 21, lithium carbonate 22, NCM particles with rhombohedral phase 23, NCM particles with a fully layered structure 25, LLZO precursor 26, nickel-cobalt-manganese hydroxide 27, precursor mixture 28, carbon nanotubes 30, short-chain carbon nanotubes 32, long-chain carbon nanotubes 34, nanoscale amorphous carbon 35, sintered powder 40, positive electrode 100, mixer 150, composite positive electrode particles 200, lithium ions 231, nickel, cobalt, and manganese ions 232, a second sintering furnace 250, LLZO particles 261, positive electrode particles coated with carbon material 300, and a first sintering furnace 400. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] Please refer to Figures 1 to 10 As shown, this case proposes a method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxides. Figure 5 As shown, the composite cathode particles 200 of this invention are mainly used in the cathode 100 of general solid-state or solid-state batteries. The cathode 100 includes a cathode substrate 10 and a cathode slurry layer 12 coated on the cathode substrate 10. The cathode slurry layer 12 includes a cathode slurry 14 with a binder and a plurality of composite cathode particles 200. The binder is such as PVDF (polyvinylidene difluoride) or PEO (polyethylene oxide). The plurality of composite cathode particles 200 account for 80 wt% to 98 wt% of the cathode slurry layer 12 by weight.

[0022] like Figure 1 and Figure 2 As shown, the method in this case includes the following steps: Step 500: Take multiple nickel-cobalt-manganese hydroxides (NCM-OH)₂₇ and place them in a first sintering furnace 400 for sintering and dehydration under a low-oxygen environment to obtain multiple nickel-cobalt-manganese oxides (NCM-O)₂₀. These multiple nickel-cobalt-manganese oxides 20 are precursors for forming NCM (lithium nickel-cobalt-manganese oxide). The structure of these multiple nickel-cobalt-manganese hydroxides 27 is a porous sphere composed of nanoscale hydroxide grains. After dehydration, these multiple nickel-cobalt-manganese hydroxides 27 may retain an uneven porous spherical shape or disintegrate into multiple single-crystal particles. Each of these nickel-cobalt-manganese hydroxides 27 is as follows: Ni x Mn y Co z (OH)₂, where x>0.8, x+y+z=1. Each of these nickel-cobalt-manganese oxides, such as Ni... x’ Mn y’ Co z’ O, where x' / (x'+y'+z ')>0.8, x'+y'+z' ≤ 1.

[0023] The "low oxygen" in this low oxygen environment refers to an atmosphere where the oxygen partial pressure is not higher than that of the atmospheric environment (i.e., the oxygen content in the atmosphere is not higher than 21%). The sintering temperature for this step is 600℃ to 900℃, and the sintering time is 3 hours to 8 hours.

[0024] Step 510: The plurality of nickel cobalt manganese oxides 20, the plurality of lithium carbonates (Li2CO3) 22, and the LLZO precursor 26 are placed into a mixer 150 and mixed to form a precursor mixture 28. The molar equivalent ratio of the plurality of nickel cobalt manganese oxides 20, the plurality of lithium carbonates 22, and the LLZO precursor 26 is 1.0 : (1.02~1.25) : (0.005~0.02). The LLZO precursor 26 is used to form LLZO, which is used to form the ceramic particles of this invention.

[0025] like Figure 7 As shown, the nickel-cobalt-manganese oxide 20 is a granular material formed by multiple particles, and the surface of the particles of the nickel-cobalt-manganese oxide 20 has multiple pores 21 or depressions. The particle size of the nickel-cobalt-manganese oxide 20 is between 1 micrometer and 5 micrometers.

[0026] Conventional techniques for manufacturing NCMs involve simultaneously placing all precursor materials—nickel cobalt manganese hydroxide, lithium carbonate, and LLZO precursor—into a sintering furnace for sintering. However, this method of sintering all materials together causes the hydroxide ions in the nickel cobalt manganese hydroxide to react chemically with the lithium carbonate first, preventing the lithium carbonate from completely decomposing into lithium oxide. Consequently, the sintering furnace contains nickel cobalt manganese hydroxide, nickel cobalt manganese oxide, lithium carbonate, lithium oxide, and other materials simultaneously. The resulting NCM particles have a rather disordered phase composition, which not only affects the appearance of the finished product but also makes them unsuitable as battery materials.

[0027] The LLZO precursor 26 is a granular material formed by multiple particles. In this case, the LLZO precursor 26 refers to all garnet solid electrolytes (such as Li7La3Zr2O) that can form a cubic crystal system (a crystal structure with a specific morphology) after co-firing with the multiple lithium carbonates 22. 12 The specific components of the product include oxides, hydroxides, carbonates, etc. The intermediate product formed after the specific components are coprecipitated or sintered has a structure with a distinct crystalline phase or a multi-component mixed amorphous structure.

[0028] The particle size of the LLZO precursor 26 is between 20 nm and 200 nm. When this LLZO precursor 26 is used to form the LLZO Li7La3Zr2O... 12In this case, the LLZO precursor 26 comprises a lithium source compound (selected from lithium oxide, lithium hydroxide, lithium carbonate, etc.), a lanthanum source compound (selected from lanthanum oxide, lanthanum hydroxide, lanthanum carbonate, etc.), and a zirconium source compound (selected from zirconium oxide, zirconium hydroxide, zirconium carbonate, etc.). The LLZO precursor 26 may also contain doping elements, such as aluminum (Al), gallium (Ga), tantalum (Ta), niobium (Nb), copper (Cu), etc., with the doping element content having an equivalent ratio to lanthanum (La) of no more than 0.25:3.

[0029] The mixer 150 is selected from three-dimensional mixers, parallel mixers, blade mixers, V-type mixers, and planetary mixers. A mixing medium is added during mixing in the mixer 150. This mixing medium is selected from zirconia beads, alumina beads, agate beads, and stainless steel beads. The filling rate of the mixing medium is 20% to 60%, which is the ratio of the total volume of the mixing medium to the mixing volume of the mixer 150. The particle diameter of the mixing medium is 0.5 cm to 2 cm.

[0030] Step 520: The precursor mixture 28 is placed in a second sintering furnace 250 for sintering. For example... Figure 10 As shown, its sintering steps are subdivided as follows: Step 520-1: First, heat the mixture to 650℃~900℃ in an atmospheric or oxygen-containing environment, so that the plurality of lithium carbonates 22 in the precursor mixture 28 melt into liquid. The melted lithium carbonates 22 will enter the plurality of pores 21 or depressions in the nickel cobalt manganese oxide 20. At the same time, the plurality of lithium carbonates 22 dissociate into a plurality of lithium oxides (Li2O). The sintering time for this step is between 1 hour and 10 hours.

[0031] Step 520-2: Next, maintain the temperature at a set temperature (between 650℃ and 900℃) while introducing oxygen. The holding time is between 1 hour and 5 hours. During this time, some of the lithium oxide in the precursor mixture 28 will initially react with each of the nickel cobalt manganese oxides 20 to form multiple NCM particles 23 with a rhombohedral crystal phase. In this crystal phase, the lithium ions 231 in the lithium oxide and the nickel, cobalt, and manganese ions 232 in the nickel cobalt manganese oxide 20 are arranged in an unstratified (i.e., mixed) state (e.g., ...). Figure 8 Meanwhile, another portion of the lithium oxide will also react with the LLZO precursor 26 to form multiple LLZO particles 261; these multiple LLZO particles 261 coat the outer surface of each of the rhombohedral NCM particles.

[0032] Step 520-3: The temperature is then increased further under an oxygen atmosphere, causing the lattice within the multiple rhombohedral NCM particles 23 to rearrange. Therefore, the arrangement between the lithium ions 231 and the nickel, cobalt, and manganese ions 232 is completely layered, forming multiple NCM particles 25 with a completely layered structure (e.g., ...). Figure 9 This process forms the composite cathode particles 200 of this case. The heating temperature in this step is 900℃~1000℃, and the sintering time is between 1 hour and 5 hours.

[0033] Step 520-4: Next, the multiple composite positive electrode particles 200 are taken out and cooled to obtain sintered powder 40 formed by the multiple composite positive electrode particles 200.

[0034] like Figure 3 and Figure 4 As shown, the melting points of the plurality of lithium carbonates 22 are lower than those of the nickel-cobalt-manganese oxide 20 and the LLZO precursor 26, so they melt first and enter the plurality of pores 21 or depressions in the nickel-cobalt-manganese oxide 20. Then, the plurality of lithium carbonates 22 decompose at high temperature into highly reactive lithium oxide (i.e., lithium oxide), which reacts with the nickel-cobalt-manganese oxide 20 to form the plurality of rhombohedral NCM particles 23. At the same time, the lithium oxide also reacts with the LLZO precursor 26 to form the plurality of LLZO particles 261. The plurality of LLZO particles 261 coat the outer surface of each rhombohedral NCM particle, and the plurality of rhombohedral NCM particles 23 with corresponding LLZO particles 261 continue to rearrange their lattice at high temperature, so that the plurality of rhombohedral NCM particles 23 form the plurality of NCM particles 25 with a fully layered structure, i.e., the plurality of composite cathode particles 200.

[0035] In step 500 of this invention, the plurality of nickel-cobalt-manganese hydroxides 27 are first sintered and dehydrated to form the plurality of nickel-cobalt-manganese oxides 20. Therefore, in the subsequent sintering process, the plurality of lithium carbonates 22 do not easily react with the hydroxide ions in the original nickel-cobalt-manganese hydroxides 27, and the plurality of lithium carbonates 22 can react completely to form the plurality of lithium oxides. The plurality of lithium oxides then react with the nickel-cobalt-manganese oxides 20 to form NCM particles 23 with a rhombohedral crystal phase. Through the action of high temperature, the composite cathode particles 200 of this invention are formed. This method of first sintering and dehydrating the plurality of nickel-cobalt-manganese hydroxides 27 to form the plurality of nickel-cobalt-manganese oxides 20 can make the final product have the correct crystal phase and a regular crystal lattice, and therefore is more suitable for battery materials.

[0036] Step 530: The sintered powder 40 is mechanically pulverized and then sieved. Preferably, the mesh size of the sieve is 500 mesh. After sieving, the D50 particle size (mass-median-diameter, MMD, the mass median particle size distribution) of the NCM particles 25 with a fully layered structure is 2 micrometers to 10 micrometers; the maximum radial dimension of the LLZO particles 261 is less than 80 nanometers.

[0037] Following step 530, steps 540A or 540B are applied to mix multiple carbon nanotubes 30 (CNTs) and multiple nanoscale amorphous carbon 35 with the sieved sintered powder 40 to form multiple carbon-coated cathode particles 300. Steps 540A and 540B use different methods to achieve this carbon material mixing, which are explained below.

[0038] Step 540A: The sintered powder 40, the plurality of carbon nanotubes 30, and the plurality of nanoscale amorphous carbon 35 are simultaneously placed into a dry stirrer (such as a planetary stirrer or a drum stirrer, not shown in the figure) for mixing to form the plurality of carbon-coated cathode particles 300. Each carbon-coated cathode particle 300 includes a corresponding composite cathode particle 200, a corresponding plurality of carbon nanotubes 30, and a plurality of nanoscale amorphous carbon 35 coating the exterior of the corresponding composite cathode particle 200 (such as...). Figure 6 The mixing speed of the dry mixer is 50 rpm to 500 rpm, and the mixing time is 2 hours to 8 hours.

[0039] Step 540B: ​​The plurality of carbon nanotubes 30 and the sintered powder 40 are mixed for the first time, and then the plurality of nanoscale amorphous carbon 35 are added for the second mixing to form the carbon-coated cathode particles 300. Each carbon-coated cathode particle 300 includes a corresponding composite cathode particle 200, a corresponding plurality of carbon nanotubes 30, and a plurality of nanoscale amorphous carbon 35 coating the exterior of the corresponding composite cathode particle 200. The first and second mixing methods are dry ball milling or wet ball milling.

[0040] The plurality of carbon nanotubes 30 include a plurality of short-chain carbon nanotubes 32 and a plurality of long-chain carbon nanotubes 34. The length of each short-chain carbon nanotube 32 is between 0.5 micrometers and 1 micrometer, and the length of each long-chain carbon nanotube 34 is between 3 micrometers and 8 micrometers. In each of the carbon-coated cathode particles 300, the weight percentage of the corresponding plurality of carbon nanotubes 30 in the corresponding composite cathode particles 200 is between 0.1 wt% and 2 wt%.

[0041] The short-chain carbon nanotubes 32 are used to bridge each LLZO particle 261 and the corresponding composite cathode particle 200, while the long-chain carbon nanotubes 34 are used to coat each composite cathode particle 200. The nanoscale amorphous carbon 35 is, for example, the amorphous carbon of the SuperP conductive agent. The size of each nanoscale amorphous carbon 35 is between 20 nanometers and 100 nanometers. Each nanoscale amorphous carbon 35 fills the gaps formed by the interlacing of the plurality of carbon nanotubes 30. In each carbon-coated cathode particle 300, the total weight of the corresponding plurality of nanoscale amorphous carbon 35 accounts for between 0.1 wt% and 2 wt% of the weight of the corresponding composite cathode particle 200.

[0042] Carbon nanotubes are used to increase electronic conductivity by forming conductive bridges around the various LLZO particles 261, allowing electrons to conduct across the composite cathode particles 200. The carbon nanotubes 30 are randomly distributed on the surface of their respective composite cathode particles 200. Because carbon nanotubes have extremely high conductivity, electrons can conduct between the different LLZO particles 261 and the composite cathode particles 200 via the carbon nanotubes 30, thus increasing the overall conductivity of the cathode 100.

[0043] The multiple nanoscale amorphous carbon 35 and the multiple carbon nanotubes 30 both serve as conductive agents. Because each nanoscale amorphous carbon 35 is in the form of particles, while each carbon nanotube 30 is in the form of elongated strips, gaps will be formed between the multiple carbon nanotubes 30 crisscrossing on the composite cathode particle 200. These gaps cannot conduct current. Therefore, by adding the corresponding nanoscale amorphous carbon 35 into these gaps, the charge can be conducted between different carbon nanotubes 30 through the bridging of the nanoscale amorphous carbon 35, further increasing the current transfer efficiency.

[0044] The advantage of this method is that the nickel-cobalt-manganese hydroxide is first dehydrated to form nickel-cobalt-manganese oxide. Therefore, during the subsequent sintering process, the lithium carbonate is less likely to react with the hydroxide ions of the original nickel-cobalt-manganese hydroxide, allowing the lithium carbonate to react completely to form lithium oxide. The lithium oxide then reacts with the nickel-cobalt-manganese oxide to form NCM particles with a rhombohedral crystal phase. High temperature then forms composite cathode particles with the correct crystal phase. This method of first dehydrating the nickel-cobalt-manganese hydroxide to form nickel-cobalt-manganese oxide ensures that the final product has the correct crystal phase and a well-ordered crystal lattice, making it more suitable for battery materials.

[0045] The above detailed description is a specific description of a feasible embodiment of this case. However, this embodiment is not intended to limit the scope of the patent in this case. All equivalent implementations or modifications that do not depart from the spirit of the technology in this case should be included in the scope of the patent in this case.

Claims

1. A method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxides, characterized in that, The composite cathode particles are used as the cathode in general solid-state or solid-state-like batteries. The method includes the following steps: Step 500: Take multiple nickel cobalt manganese hydroxides and place them in a first sintering furnace for sintering and dehydration in a low-oxygen environment to obtain multiple nickel cobalt manganese oxides, which are precursors for forming NCM. Step 510: The multiple nickel cobalt manganese oxides, multiple lithium carbonates and LLZO precursors are placed into a mixer for mixing to form a precursor mixture; The nickel-cobalt-manganese oxide is a granular material formed by multiple particles, and the surface of the nickel-cobalt-manganese oxide particles has multiple pores or depressions. Step 520: The precursor mixture is placed in a second sintering furnace for sintering; Its sintering process is further divided into: Step 520-1: First, heat the mixture to 650℃~900℃ in an atmospheric or oxygen-containing environment to melt the multiple lithium carbonates in the precursor mixture into liquid. The melted lithium carbonates enter the multiple pores or depressions of the nickel-cobalt-manganese oxide. At the same time, the multiple lithium carbonates decompose into multiple lithium oxides. The sintering time for this step is between 1 hour and 10 hours. Step 520-2: Next, maintain the temperature at the set level and introduce oxygen; The set temperature is between 650℃ and 900℃; the holding time is between 1 hour and 5 hours; at this time, part of the lithium oxide in the precursor mixture will react with each of the nickel cobalt manganese oxides to form multiple NCM particles with rhombohedral crystal phase. In this rhombohedral crystal phase, the lithium ions in the lithium oxide and the nickel, cobalt and manganese ions in the nickel cobalt manganese oxide are arranged in an unlayered state, that is, they are mixed together; at the same time, another part of the lithium oxide will also react with the LLZO precursor to form multiple LLZO particles; the multiple LLZO particles are coated on the outer surface of each of the NCM particles with rhombohedral crystal phase. Step 520-3: Then, the temperature is further increased under an oxygen atmosphere, causing the lattice within the multiple NCM particles with rhombohedral crystal phases to rearrange. As a result, the arrangement between the lithium ions and the nickel, cobalt, and manganese ions is completely layered to form NCM particles with a completely layered structure, i.e., multiple composite cathode particles are formed. The heating temperature in this step is 900℃~1000℃, and the sintering time is between 1 hour and 5 hours. Step 520-4: Next, the multiple composite cathode particles are removed and cooled to obtain sintered powder formed by the multiple composite cathode particles; The lithium carbonate has a lower melting point than the nickel cobalt manganese oxide and the LLZO precursor, so it will melt first and enter the multiple pores or depressions of the nickel cobalt manganese oxide to react with it. The multiple NCM particles with rhombohedral phase and corresponding LLZO particles will then rearrange their lattice at high temperature to generate multiple corresponding composite cathode particles.

2. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, The structure of these multiple nickel-cobalt-manganese hydroxides is a porous spherical shape composed of nano-sized hydroxide grains. After dehydration, these multiple nickel-cobalt-manganese hydroxides may retain the porous spherical shape with an uneven surface or disintegrate into multiple single-crystal particles. The nickel-cobalt-manganese hydroxides are selected from Ni x Mn y Co z (OH)₂, where x>0.8, x+y+z=1; the chemical formula of this nickel-cobalt-manganese oxide is Ni x’ Mn y’ Co z’ O, where x' / (x'+y'+z ')>0.8, x'+y'+z' ≤ 1.

3. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, In step 500, the "low oxygen" in the low oxygen environment refers to an atmosphere where the oxygen partial pressure is not higher than that of the atmospheric environment, that is, the oxygen content in the atmosphere is not higher than 21%. The sintering temperature in step 500 is 600°C to 900°C, and the sintering time is 3 hours to 8 hours.

4. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, In step 510, the molar equivalent ratio of the plurality of nickel cobalt manganese oxides, the plurality of lithium carbonates, and the LLZO precursor is 1.0:(1.02~1.25):(0.005~0.02); the LLZO precursor is used to form LLZO, which is used to form ceramic particles; the particle size of the nickel cobalt manganese oxides is between 1 micrometer and 5 micrometers; the particle size of the LLZO precursor is between 20 nm and 200 nm.

5. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, The LLZO precursor refers to all specific components that form cubic garnet solid electrolytes after co-firing with the lithium source. These specific components include at least one of oxides, hydroxides, and carbonates. The intermediate products formed after co-precipitation or sintering of these specific components have a structure with a distinct crystalline phase or a multi-component mixed amorphous structure.

6. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 5, characterized in that, The garnet solid electrolyte is Li7La3Zr2O. 12 The LLZO precursor comprises a lithium source compound, a lanthanum source compound, and a zirconium source compound; wherein the lithium source compound is selected from at least one of lithium oxide, lithium hydroxide, and lithium carbonate; the lanthanum source compound is selected from at least one of lanthanum oxide, lanthanum hydroxide, and lanthanum carbonate; and the zirconium source compound is selected from at least one of zirconium oxide, zirconium hydroxide, and zirconium carbonate.

7. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 5, characterized in that, The LLZO precursor also contains at least one of the following doping elements: aluminum, gallium, tantalum, niobium, and copper.

8. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, The mixer adds a mixing medium during the mixing process, which is selected from zirconium oxide beads, aluminum oxide beads, agate beads, and stainless steel beads. The filling rate of the mixing medium is 20% to 60%, which is the ratio of the total volume of the mixing medium to the mixing volume of the mixer; the particle diameter of the mixing medium is 0.5 cm to 2 cm.

9. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 1, characterized in that, It also includes: Step 530: mechanically crushing the sintered powder and then sieving it with a sieve; wherein after sieving, the D50 particle size of the NCM particles is 2 micrometers to 10 meters; and the maximum radial dimension of each LLZO particle is less than 80 nanometers.

10. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 9, characterized in that, After step 530, multiple carbon nanotubes, multiple nanoscale amorphous carbon, and the sintered powder after sieving are mixed to form multiple positive electrode particles coated with carbon material.

11. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 10, characterized in that, The plurality of carbon nanotubes include short-chain carbon nanotubes and long-chain carbon nanotubes. The length of the short-chain carbon nanotubes is between 0.5 micrometers and 1 micrometer, and the length of the long-chain carbon nanotubes is between 3 micrometers and 8 micrometers. The short-chain carbon nanotubes are used to bridge each LLZO particle and the corresponding composite cathode particle. The long-chain carbon nanotubes are used to coat the composite cathode particle.

12. The method for manufacturing composite cathode particles coated with ceramic particles using nickel-cobalt-manganese oxide as described in claim 10, characterized in that, The amorphous carbon at the nanoscale ranges in size from 20 nanometers to 100 nanometers; each amorphous carbon at this nanoscale fills the gaps formed by the interlacing of multiple carbon nanotubes.

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