Method for manufacturing positive electrode particles coated with ceramic particles by using dry-type one-time sintering process
By coating NCM particles with LLZO particles and then with carbon nanotubes and amorphous carbon, and employing a dry one-step sintering process, the problems of interfacial side reactions and high costs associated with two-stage sintering are solved, achieving highly efficient lithium-ion and electron conduction. This makes it suitable as a cathode material for solid-state or near-solid-state batteries.
Patent Information
- Application Number
- CN202512055879.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-01-03
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-24
AI Technical Summary
In existing technologies, side reactions are prone to occur at the interface of cathode particles, leading to reduced lifespan and low electronic conductivity. Furthermore, the two-stage sintering method is costly and time-consuming.
A dry one-time sintering process is used to coat NCM particles with LLZO particles, and carbon nanotubes and nanoscale amorphous carbon are coated on the outside of the cathode particles. Through one-time sintering, cathode particles with ceramic particles are formed, which improves conductivity and production efficiency.
It improves the conductivity and electronic conductivity of lithium ions, reduces manufacturing costs and time, and is suitable as a cathode material for solid-state or solid-state-like batteries.
Smart Images
Figure CN121922602A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery cathode material technology, and in particular to a method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process. 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) or a mixture 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] The conventional method for manufacturing NCM composite cathode particles coated with ceramic particles employs a two-stage sintering process. However, this method requires two-stage sintering, which incurs significant costs and time, leading to increased manufacturing costs. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method for manufacturing positive electrode particles coated with ceramic particles using a dry one-time sintering process, thereby improving production efficiency and reducing time costs by using dry and one-time sintering to form positive electrode particles with ceramic particles.
[0006] Therefore, the purpose of this case is to solve the problems of the aforementioned prior art. This case proposes a method for manufacturing cathode particles coated with ceramic particles using a dry one-step sintering process, in which LLZO particles are coated onto the outer surface of the NCM particles. The LLZO particles have the ability to accommodate and homogenize lithium ions, and can disperse the lithium ion pathway, thus providing better lithium ion conduction. This case utilizes a one-step sintering process to form the cathode particles from NCM and LLZO precursors, reducing process complexity, processing time, and production costs. The cathode particles are further coated with carbon nanotubes and nanoscale amorphous carbon, which increases the electron conduction efficiency of the cathode particles. The cathode with the cathode particles of this case can serve as a ternary cathode.
[0007] To achieve the above objectives, this invention proposes a method for manufacturing cathode particles coated with ceramic particles using a dry one-step sintering process. These cathode particles are used as the cathode in solid-state or near-solid-state batteries. The method includes the following steps: Step A: Multiple nickel-cobalt-manganese precursors, a lithium source, and an LLZO precursor are placed in a mixer for mixing to form a precursor mixture; each nickel-cobalt-manganese precursor has multiple pores on its surface; the nickel-cobalt-manganese precursor is used to form NCM (lithium nickel cobalt manganese oxide); the LLZO precursor is used to form LLZO, which is used to form the ceramic particles; Step B: The precursor mixture is placed in a sintering furnace for further processing. Oxygen sintering is performed to obtain a sintered powder formed by multiple cathode particles. The melting point of the lithium source is lower than that of the nickel-cobalt-manganese precursor and the LLZO precursor, so that the lithium source melts first and enters the pores of the nickel-cobalt-manganese precursor. Then, the lithium source decomposes into highly reactive lithium oxide at high temperature. The lithium oxide reacts with the nickel-cobalt-manganese precursor to form multiple NCM (lithium nickel cobalt-manganese oxide) particles. At the same time, the lithium oxide also reacts with the LLZO precursor to form multiple LLZO particles. The multiple LLZO particles coat the outer surface of each NCM particle, and the NCM particles with corresponding LLZO particles form corresponding 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 positive electrode particles in this case.
[0010] Figure 2 This shows a flowchart of the manufacturing process of the cathode particles in this case.
[0011] Figure 3 This shows a structural diagram of the positive electrode particles in this case.
[0012] Figure 4 This shows a cross-sectional view of the positive electrode 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 precursor in this case.
[0016] Among them, the positive electrode substrate is 10, the positive electrode slurry layer is 12, the positive electrode slurry is 14, the nickel-cobalt-manganese precursor is 20, the pores are 21, the lithium source is 22, the LLZO precursor is 26, the precursor mixture is 28, the carbon nanotubes are 30, the short-chain carbon nanotubes are 32, the long-chain carbon nanotubes are 34, the nano-grade amorphous carbon is 35, the sintered powder is 40, the positive electrode is 100, the mixer is 150, the positive electrode particles are 200, the NCM particles are 201, the sintering furnace is 250, the LLZO particles are 261, and the positive electrode particles coated with carbon material are 300. Detailed Implementation
[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0018] Please refer to Figures 1 to 7 As shown, this case proposes a method for manufacturing cathode particles coated with ceramic particles using a dry one-step sintering process. For example... Figure 5 As shown, the positive electrode particles 200 of this invention are mainly used in the positive electrode 100 of general solid-state or solid-state-like batteries. The positive electrode 100 includes a positive electrode substrate 10 and a positive electrode slurry layer 12 coated on the positive electrode substrate 10. The positive electrode slurry layer 12 includes a positive electrode slurry 14 with a binder and a plurality of positive electrode particles 200. The binder is such as PVDF (polyvinylidene difluoride), PEO (polyethylene oxide), etc. The plurality of positive electrode particles 200 account for 80 wt% to 98 wt% of the weight percentage of the positive electrode slurry layer 12.
[0019] like Figure 1 and Figure 2 As shown, the method in this case includes the following steps: Step 500: The nickel-cobalt-manganese precursor 20, lithium source 22, and LLZO precursor 26 are placed in a mixer 150 and mixed to form a precursor mixture 28. The molar equivalent ratio of the nickel-cobalt-manganese precursor 20, the lithium source 22, and the LLZO precursor 26 is 1.0:(1.02~1.25):(0.005~0.02). The nickel-cobalt-manganese precursor 20 is a precursor for forming NCM (lithium nickel cobalt manganese oxide); the LLZO precursor 26 is a precursor for forming LLZO, which is used to form the ceramic particles of this invention.
[0020] like Figure 7 As shown, the nickel-cobalt-manganese precursor 20 is a granular material formed by multiple particles, and the surface of the particles of the nickel-cobalt-manganese precursor 20 has multiple pores 21. The particle size of the nickel-cobalt-manganese precursor 20 is between 1 micrometer and 5 micrometers. Preferably, the nickel-cobalt-manganese precursor 20 is a porous spherical nickel-cobalt-manganese precursor composed of needle-like grains, such as Ni xMn y Co z (OH)2, where x>0.8, x+y+z=1.
[0021] The lithium source 22 is selected from at least one of lithium hydroxide (LiOH), lithium carbonate (Li2CO3), lithium nitrate (LiNO3), or a mixture thereof.
[0022] 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 lithium source 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.
[0023] 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... 12 In 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.
[0024] 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.
[0025] Step 510: The precursor mixture 28 is placed in a sintering furnace 250 for aerobic sintering. First, the temperature is raised to 400°C to 700°C under a pure oxygen atmosphere and maintained for 1 to 4 hours, so that the lithium source 22 in the precursor mixture 28 is completely melted and the other substances in the precursor mixture 28 are fully mixed. Then, the temperature is raised to 800°C to 1000°C and maintained for 6 to 12 hours. Finally, the temperature is naturally cooled to room temperature under a pure oxygen atmosphere to obtain sintered powder 40 formed by multiple positive electrode particles 200.
[0026] like Figure 3 and Figure 4 As shown, the lithium source 22 has a lower melting point than the nickel-cobalt-manganese precursor 20 and the LLZO precursor 26, therefore it melts first and enters the multiple pores 21 of the nickel-cobalt-manganese precursor 20. Then, the lithium source 22 decomposes at high temperature into highly reactive lithium oxide, which reacts with the nickel-cobalt-manganese precursor 20 to form multiple NCM (lithium nickel cobalt-manganese oxide) particles 201. Simultaneously, the lithium oxide also reacts with the LLZO precursor 26 to form multiple LLZO particles 261. These multiple LLZO particles 261 coat the outer surface of each NCM particle 201, and the NCM particle 201 with the corresponding LLZO particles 261 forms the corresponding positive electrode particle 200.
[0027] Step 520: 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) of the NCM particles 201 is 2 to 10 micrometers; the maximum radial dimension of the LLZO particles 261 is less than 80 nanometers.
[0028] Following step 520, steps 530A or 530B 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 530A and 530B achieve this carbon mixing using different methods, which are explained below.
[0029] Step 530A: 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 cathode particle 200, a corresponding plurality of carbon nanotubes 30, and a plurality of nanoscale amorphous carbon 35 coating the exterior of the corresponding 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.
[0030] Step 530B: 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 cathode particle 200, a corresponding plurality of carbon nanotubes 30, and a plurality of nanoscale amorphous carbon 35 coating the exterior of the corresponding cathode particle 200. The first and second mixing methods are dry ball milling or wet ball milling.
[0031] 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 positive electrode particles 300 coated with carbon material, the weight percentage of the corresponding plurality of carbon nanotubes 30 in the corresponding positive electrode particle 200 is between 0.1 wt% and 2 wt%.
[0032] The short-chain carbon nanotubes 32 are used to bridge each LLZO particle 261 and the corresponding cathode particle 200, while the long-chain carbon nanotubes 34 are used to coat each cathode particle 200. The nanoscale amorphous carbon 35 is, for example, the amorphous carbon of the Super P 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 cathode particle 300 coated with carbon material, 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 cathode particle 200.
[0033] Carbon nanotubes are used to increase electronic conductivity by forming conductive bridges around the various LLZO particles 261, allowing electrons to conduct across the positive electrode particles 200. The carbon nanotubes 30 are randomly distributed on the surface of their respective positive electrode particles 200. Because carbon nanotubes have extremely high conductivity, electrons can conduct between the different LLZO particles 261 and the positive electrode particles 200 via the carbon nanotubes 30, thus increasing the overall conductivity of the positive electrode 100.
[0034] 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 positive electrode 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.
[0035] The advantage of this invention lies in coating the NCM particles with LLZO particles. These LLZO particles possess the ability to accommodate and homogenize lithium ions, and can disperse the lithium ion pathways, thus providing better lithium ion conduction. This invention utilizes a single sintering process to form the cathode particles from the NCM and LLZO precursors, reducing process complexity, processing time, and production costs. The cathode particles are further coated with carbon nanotubes and nanoscale amorphous carbon, which increases electron conductivity on the cathode particles. The cathode with these cathode particles can then serve as a ternary cathode.
[0036] 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 cathode particles coated with ceramic particles using a dry one-step sintering process, characterized in that, The positive electrode particle is used as the positive electrode in a solid-state or solid-state-like battery, and the method includes the following steps: Step A: Multiple nickel-cobalt-manganese precursors, a lithium source, and an LLZO precursor are placed in a mixer and mixed to form a precursor mixture; each nickel-cobalt-manganese precursor has multiple pores on its surface; the nickel-cobalt-manganese precursor is used to form NCM; the LLZO precursor is used to form LLZO, which is used to form the ceramic particles; LLZO is lithium lanthanum zirconium oxide, and NCM is lithium nickel cobalt manganese oxide. Step B: The precursor mixture is placed in a sintering furnace for aerobic sintering to obtain sintered powder formed by multiple cathode particles; wherein the melting point of the lithium source is lower than that of the nickel-cobalt-manganese precursor and the LLZO precursor, so that the lithium source will melt first and enter the pores of the nickel-cobalt-manganese precursor; then the lithium source decomposes into highly reactive lithium oxide at high temperature, and the lithium oxide reacts with the nickel-cobalt-manganese precursor to form multiple NCM particles; at the same time, the lithium oxide also reacts with the LLZO precursor to form multiple LLZO particles; the multiple LLZO particles coat the outer surface of each NCM particle, and the NCM particles with corresponding LLZO particles form the corresponding cathode particles.
2. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, The molar equivalent ratio of the nickel-cobalt-manganese precursor, the lithium source, and the LLZO precursor is 1.0:(1.02~1.25):(0.005~0.02).
3. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, The size of the nickel-cobalt-manganese precursor ranges from 1 micrometer to 5 micrometers.
4. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, The nickel-cobalt-manganese precursor is a porous spherical nickel-cobalt-manganese precursor composed of needle-like grains.
5. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, The nickel-cobalt-manganese precursor is Ni x Mn y Co z (OH)2, x>0.8, x+y+z=1.
6. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, The lithium source is selected from at least one of lithium hydroxide, lithium carbonate, lithium nitrate, or a mixture thereof.
7. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process 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.
8. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 7, 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.
9. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 7, characterized in that, The LLZO precursor also contains at least one of the following doping elements: aluminum, gallium, tantalum, niobium, and copper.
10. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, In step A, the mixer is selected from three-dimensional mixers, parallel mixers, blade mixers, V-type mixers, and planetary mixers; and when mixing in the mixer, a mixing medium is added, which 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; the particle diameter of the mixing medium is 0.5 cm to 2 cm.
11. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, In step B, the aerobic sintering system is first heated to 400°C to 700°C in a pure oxygen atmosphere and held at that temperature for 1 to 4 hours, so that the lithium source in the precursor mixture is completely melted and the other substances in the precursor mixture are fully mixed. Then, the temperature is raised to 800°C to 1000°C and held at that temperature for 6 to 12 hours. Finally, it is naturally cooled to room temperature in a pure oxygen atmosphere.
12. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 1, characterized in that, It also includes: Step C: mechanically crushing the sintered powder and then sieving it through a sieve.
13. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 12, characterized in that, After sieving, the D50 particle size of the NCM particles ranges from 2 micrometers to 10 meters; the maximum radial dimension of each LLZO particle is less than 80 nanometers.
14. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 12, characterized in that, After step C, 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; wherein carbon nanotubes are abbreviated as CNTs.
15. The method for manufacturing cathode particles coated with ceramic particles using a dry one-time sintering process as described in claim 14, characterized in that, The plurality of carbon nanotubes includes 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 cathode particle. The long-chain carbon nanotubes are used to coat the cathode particle. The nanoscale amorphous carbon has a size between 20 nanometers and 100 nanometers. Each nanoscale amorphous carbon system fills the gaps formed by the interlacing of the plurality of carbon nanotubes.