A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process.

Abstract

A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process includes the following steps: Step 500: Take multiple large NCM (lithium nickel cobalt manganese oxide) particles, and simultaneously place the large NCM particles and the glass phase material into a first mixer. Use high-speed rotation to thoroughly stir them to ensure uniform mixing. The glass phase material will be wholly or partially attached to the surface of the large NCM particles, thus forming a large NCM particle with a glass phase layer. The glass phase material is a non-crystalline solid electrolyte with a lithium-ion conductivity higher than 10⁻⁵ S / cm. Step 510: Simultaneously place multiple fine LLZO (lithium lanthanum zirconium oxide) particles and the large NCM particles with the glass phase layer into a second mixer. Use high-speed rotation to thoroughly stir them to ensure uniform mixing. Under high-speed rotation, the fine LLZO particles are distributed within or on the surface of the glass phase layer, thus forming multiple composite NCM particles.

Description

[Technical Field] This work relates to cathode materials, and in particular to a method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process. [Previous Technology] To increase conductivity, multiple positive electrode particles are typically filled into the positive electrode slurry. These particles can be made of materials such as NCM (lithium nickel manganese cobalt oxide), LMFP (lithium manganese iron phosphate), or mixtures thereof, and are distributed throughout the slurry. However, the interfaces of these positive electrode particles in conventional technology are prone to side reactions, leading to a decrease in the lifespan of the positive electrode and low electron conductivity, resulting in poor overall battery performance. To improve coating integrity, it is necessary to coat the surface of the cathode particles with a glass phase layer. Common methods for fabricating glass phase layers involve high-temperature melting and quenching, with adjustments to heat treatment conditions to prevent the material's crystal lattice from forming an ordered arrangement at room temperature. However, this approach is more suitable for glass phase oxide materials that can withstand prolonged heating, such as garnet, perovskite, or phosphates. Conversely, for non-oxide glass phase materials with poor high-temperature resistance, such as halide and sulfide systems, excessively long heating and holding times can actually decrease their lithium-ion conductivity. Therefore, this invention aims to propose a method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotating process. By utilizing the energy exchange generated when the glass-phase solid electrolyte precursor collides with the surface of the NCM particles at high speed, a short-duration high-temperature pulse is created, causing the precursor to react and produce the glass-phase solid electrolyte. Since this instantaneous high-temperature effect is localized, short-lived, and cools down rapidly, it prevents material performance degradation caused by prolonged high-temperature exposure. Furthermore, by modifying the process parameters, this method is also applicable to oxide system electrolytes. [Summary of the Invention] Therefore, the purpose of this invention is to solve the aforementioned problems in the prior art. This invention proposes a method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotating process. The method involves coating the outer surface of the large NCM particles with a glass phase material to form a glass phase layer. This glass phase layer can prevent direct contact between the large NCM particles and the electrolyte, reducing interfacial side reactions; simultaneously, it reduces the interfacial impedance of lithium ions entering and exiting the large NCM particles, improving rate charge / discharge performance. Furthermore, the presence of the glass phase layer can accommodate volume changes during charge / discharge, improving the mechanical properties of the powder and reducing breakage. The large NCM particles are then coated with numerous fine LLZO particles. These fine LLZO particles have the ability to accommodate and equalize lithium ions. Therefore, when lithium ions pass through the cathode, the dispersed LLZO particles can guide and disperse the lithium ion pathway, resulting in a better lithium ion pathway design. This invention further coats the outer surface of the large NCM particles coated with fine LLZO particles with carbon nanotubes and nanoscale amorphous carbon. This allows electrons to conduct on the composite NCM large particles, and the amorphous carbon at each nanometer level can fill the gaps formed by the interlacing of multiple carbon nanotubes, creating a more complete electron conduction path. The architecture of this invention can provide stability to the overall cathode slurry structure, thus reducing the amount of cobalt used. To achieve the above objectives, this invention proposes a method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process. The cathode particles are present in the cathode of a solid-state or near-solid-state battery. The process for manufacturing the cathode particles includes the following steps: Step 510: Take NCM (lithium nickel cobalt manganese oxide) material, wherein the NCM material consists of multiple large NCM particles, wherein the large NCM particles are irregularly cubic in shape; simultaneously place the large NCM particles and the glass phase material into a first mixer, and use high-speed rotation to thoroughly stir them to ensure uniform mixing. Under high-speed rotation, the glass phase material will adhere entirely or partially to the surface of the large NCM particles to form a glass phase layer, thus forming large NCM particles with a glass phase layer. The phase layer can block direct contact between the NCM large particles and the electrolyte, reducing interface side reactions; at the same time, it reduces the interface resistance of lithium ions entering and leaving the NCM large particles; the glass phase material is a non-crystalline oxide or non-oxide solid electrolyte with a lithium ion conductivity higher than 10-5 S / cm; Step 510: Mix the LLZO (lithium lanthanum zirconium oxide) material with the NCM large particles with the glass phase layer, wherein the LLZO material is multiple LLZO fine particles; the NCM large particles with the glass phase layer and the LLZO fine particles are simultaneously placed into a second mixer and stirred at high speed to make them uniformly mixed. Under high speed rotation, the LLZO fine particles are distributed in the glass phase layer or on the surface of the glass phase layer, and the whole forms multiple composite NCM large particles. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process further includes step C as follows: Multiple composite NCM large particles, multiple CNT (Carbon Nanotubes), and multiple nanoscale amorphous carbon are mixed with carbon materials to form carbon-coated cathode particles. The features and advantages of this work will be further explained in the following description; please refer to the accompanying drawings while reading. [Simplified Explanation of the Diagram] Figure 1 shows the manufacturing process of the cathode particle in this case. Figure 2 shows the structure of the positive electrode particle in this case. Figure 3 shows the structural diagram of the positive electrode in this case. Figure 4 shows the structural diagram of the composite NCM large particles in this case. Figure 5 shows the structural diagram of the composite NCM large particles in this case. Figure 6 shows the structural diagram of the composite NCM large particles in this case.

Implementation Method

Claims

1. A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process, wherein the cathode particles are present in the cathode of a solid-state or near-solid-state battery, and the process for manufacturing the cathode particles includes the following steps: Step 500: Take NCM (lithium nickel cobalt manganese oxide) material, wherein the NCM material is multiple large NCM particles; simultaneously place the large NCM particles and the glass phase material into a first mixer, and use high-speed rotation to thoroughly stir them to achieve uniform mixing. Under high-speed rotation, the glass phase material will adhere to all or part of the surface of the large NCM particles to form a glass phase layer, i.e., the entire NCM large particles with a glass phase layer are formed; wherein the glass phase layer can prevent the large NCM particles from contacting the electrolyte. Direct contact of the material reduces interfacial side reactions; at the same time, it reduces the interfacial resistance of lithium ions entering and leaving the NCM large particles; the glass phase material is a non-crystalline oxide or non-oxide solid electrolyte with a lithium ion conductivity higher than 10-5 S / cm; Step 510: Mix the LLZO (lithium lanthanum zirconium oxide) material with the NCM large particles with the glass phase layer, wherein the LLZO material is multiple LLZO fine particles; the NCM large particles with the glass phase layer and the LLZO fine particles are simultaneously placed into a second mixer and stirred at high speed to make them uniformly mixed. Under high speed rotation, the LLZO fine particles are distributed in the glass phase layer or on the surface of the glass phase layer, and the whole forms multiple composite NCM large particles.

2. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein the size of the large NCM particles is 3 to 5 micrometers; it is a single crystal structure; the thickness of the glass phase layer is between 5 nanometers and 100 nanometers; and in step 510, the maximum radial dimension of the fine LLZO particles is less than 40 nanometers.

3. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein in step 500, the first mixer is selected from a three-dimensional mixer or a flat roller mixer; or a DC blade mixer; anhydrous alcohol or isopropanol solvent is added to the DC blade mixer and stirred thoroughly to make the two uniformly mixed.

4. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein in step 500, the rotation speed of the first mixer is 50 rpm to 3000 rpm, and the stirring time is 10 minutes to 12 hours; oxygen or dry air is introduced during the mixing process to protect the large NCM particles during high-speed rotation and prevent the large NCM particles from decomposing at high temperatures; wherein the oxygen or dry air is added at a rate of 0.5 liters / minute to 5 liters / minute.

5. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein the glass phase material is selected from at least one of the following: lithium oxides of groups IIIA, IVA, and VA; lithium halides / halo-oxides; lithium sulfides; amorphous oxide-based solid electrolytes; amorphous perovskite-based solid electrolytes; garnet-based solid electrolytes; or lithium-phosphorus-oxynitrides.

6. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein the glass phase material is selected from Li2O-ROx, wherein R = at least one of B (boron), Al (aluminum), Si (silicon), Ge (germanium), P (phosphorus), and As (arsenic), and x = 1 to 3; Li-MO, wherein M is at least one of the halogens F (fluorine), Cl (chlorine), Br (bromine), and I (iodine); Li2S-P2S5; LLTO; LLZO; LiPON; and at least one of the above.

7. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein the LLZO in the LLZO fine particles is selected from at least one of Ga-LLZO (gallium-doped lithium lanthanum zirconium oxide), Cu-LLZO (copper-doped lithium lanthanum zirconium oxide), Ta-LLZO (tantalum-doped lithium lanthanum zirconium oxide), Sr-LLZO (strontium-doped lithium lanthanum zirconium oxide), and Al-LLZO (aluminum-doped lithium lanthanum zirconium oxide).

8. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein the LLZO is selected from Cua,Xb-LLZO (copper-doped lithium lanthanum zirconium oxide), and the X series is selected from Ga (gallium), Ta (tantalum), Sr (strontium), Ba (barium), and Al (aluminum), wherein a+b=0.25 to 0.8, and a>0.1; the use of copper doping in LLZO can make the overall structure more stable, the lithium ion channels can be smoother, and the sintering speed can be increased while the manufacturing cost is relatively low; and it can reduce the formation of lithium carbonate when the material is exposed to air; that is, it can increase the surface stability of the entire material during sintering.

9. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein in a single NCM cathode particle coated with LLZO and a glass phase, the total weight of all the fine LLZO particles is between 0.2 wt% and 2 wt% of the weight of the large NCM particle with the glass phase layer.

10. A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, wherein in step 510, the rotation speed of the second mixer is 50 rpm to 3000 rpm, the stirring time is 10 minutes to 12 hours, and oxygen or dry air is introduced during the mixing process to protect the large NCM particles during high-speed rotation and prevent the large NCM particles from decomposing at high temperatures; wherein the oxygen or dry air is added at a rate of 0.5 liters / minute to 5 liters / minute.

11. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 1, further comprising step 520: mixing the plurality of composite NCM large particles, the plurality of CNTs (Carbon Nanotubes), and the plurality of nanoscale amorphous carbons to form cathode particles coated with carbon materials.

12. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the carbon material mixing method is as follows: the plurality of composite NCM large particles, the plurality of CNTs, and the plurality of nano-level amorphous carbons are simultaneously placed in a dry stirrer for mixing, so that the CNTs and the nano-level amorphous carbons coat the composite NCM large particles to form the carbon-coated cathode particles; wherein the stirring speed of the dry stirrer is 50 rpm to 500 rpm, and the stirring time is 2 hours to 8 hours.

13. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the carbon material is mixed by first mixing the CNT with the plurality of composite NCM large particles, and then mixing it with nano-level amorphous carbon to form the carbon-coated cathode particles; wherein the CNT is first mixed with the plurality of composite NCM large particles by dry ball milling or wet ball milling.

14. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 13, wherein the dry ball milling mixing method involves first placing the CNTs and the plurality of composite NCM large particles directly into a dry ball mill for ball milling, wherein the rotation speed of the dry ball mill is between 50 rpm and 1000 rpm, the mixing time is between 20 minutes and 12 hours, and the ball milling is carried out at room temperature to 50 degrees Celsius; then the nano-level amorphous carbon is added and mixed, so that the CNTs and nano-level amorphous carbon coat the composite NCM large particles to form the cathode particles coated with carbon material.

15. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotational process as described in claim 13, wherein the wet ball milling mixing method involves first dispersing the CNT in a dispersant and then placing it together with the plurality of composite NCM large particles into a wet ball mill for wet ball milling, wherein the rotational speed of the wet ball mill is between 50 rpm and 500 rpm and the mixing time is between 20 minutes and 12 hours; wherein the dispersant is selected from a polar or non-polar non-aqueous organic solvent; and then the nano-level amorphous carbon is added for mixing, so that the CNT and the nano-level amorphous carbon coat the composite NCM large particles to form the cathode particles coated with carbon material.

16. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the size of the nanoscale amorphous carbon is between 20 nanometers and 100 nanometers; each nanoscale amorphous carbon is mainly located between the voids formed by the multiple CNTs; and the total weight of the nanoscale amorphous carbon accounts for between 0.1 wt% and 2 wt% of the weight of a single composite NCM particle.

17. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the CNT is a short-chain CNT and a long-chain CNT, the short-chain CNT having a length between 0.5 micrometers and 1 micrometer, and the long-chain CNT having a length between 3 micrometers and 8 micrometers; the short-chain CNT is used to bridge the LLZO fine particles and the NCM large particles; the long-chain CNT is used to coat the composite NCM large particles.

18. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the total weight of the CNT accounts for 0.1 wt% to 2 wt% of the weight of a single NCM particle.

19. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein (the CNT + the nano-level amorphous carbon): a single composite NCM particle = (0.09 to 3): 100, which is a weight ratio.

20. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a high-speed rotation process as described in claim 11, wherein the CNT: the nanoscale amorphous carbon: the single composite NCM large particle = 0.5:1:100, which is a weight ratio.

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