A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process.

Abstract

A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process, wherein the cathode particle manufacturing process includes the following steps: Step 500: Multiple NCM large particles and the glass phase material are simultaneously placed into a first mixer to uniformly mix them; the glass phase material is a non-crystalline solid electrolyte with a lithium-ion conductivity higher than 10⁻⁵ S / cm; Step 510: The mixed NCM large particles and the glass phase material are subjected to aerobic sintering to form NCM large particles with a glass phase layer; Step 520: Multiple LLZO fine particles and the NCM large particles with the glass phase layer are placed into a second mixer to mix and form composite NCM large particles; Step 530: The composite NCM large particles are then subjected to aerobic sintering to eliminate the interfacial resistance between the LLZO fine particles and the NCM large particles during lithium-ion transport; a plurality of sintered powders are formed. The method further includes step 540 of mixing the sintered powder with a carbon material.

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 sintering process. [Previous Technology] A battery is primarily formed by placing a positive electrode and a negative electrode in an electrolyte. The positive electrode consists of numerous positive electrode conductive units (positive electrode materials, such as lithium cobalt oxide) mixed and dispersed in a slurry. Generally, the positive electrode conductive units must first be mixed with the conductive slurry before being applied to the electrode sheets and assembled into a battery. Therefore, the numerous positive electrode conductive units (positive electrode materials) are connected to each other through the conductive slurry. Thus, the conductive slurry must possess conductivity or enhance conductivity to allow free electrons to migrate between different positive electrode conductive units without consuming excessive energy due to internal resistance, thereby achieving effective conductivity. Therefore, the conductivity of the slurry must be adjusted using specific conductive materials during its manufacturing process. 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. Based on extensive experience with battery materials, the applicant proposes a novel design to further enhance the conductivity of the slurry. This design involves adding carbon nanotubes and nanoscale amorphous carbon to coat the cathode particles in the battery's cathode material, thereby improving the overall conductivity of the cathode. Furthermore, coating the surface of these cathode particles with a glass phase material reduces interfacial impedance, improves powder coating properties, stabilizes the powder in the electrolyte, and prevents interfacial side reactions. [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 sintering 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 homogenize 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 sintering process. The cathode particles are present in the cathode of a solid-state or near-solid-state battery. The manufacturing process of the cathode particles includes the following steps: Step 500: 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 stir thoroughly to ensure uniform mixing; the glass phase material is a non-crystalline solid electrolyte with a lithium-ion conductivity higher than 10⁻⁵ S / cm; Step 510: Then, perform oxygen-enriched sintering of the stirred NCM particles and the glass phase material; after sintering, the NCM particles are coated with a glass phase layer formed by the glass phase material, thus forming a glass phase... The glass phase layer can block the direct contact between the NCM large particles and the electrolyte, reducing interface side reactions; at the same time, it reduces the interface impedance of lithium ions entering and leaving the NCM large particles; Step 520: Mix 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 above-mentioned NCM large particles with the glass phase layer and the LLZO fine particles are simultaneously placed in a second mixer and stirred thoroughly to make them uniformly mixed. After stirring, the LLZO fine particles are distributed in the glass phase layer or on the surface of the glass phase layer, and the whole is formed into composite NCM large particles; Step 530: Then, the above-mentioned composite NCM large particles are subjected to oxygen sintering, and the sintering process is used to eliminate the interface impedance between the LLZO fine particles and the NCM large particles during lithium ion transport; the whole is formed into a plurality of sintered powders. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process further includes step 540: mixing the sintered powder, multiple CNTs (Carbon Nanotubes), and multiple nanoscale amorphous carbon materials. 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 sintering 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: Taking NCM (lithium nickel cobalt manganese oxide) material, wherein the NCM material is a plurality of large NCM particles; wherein the large NCM particles are cubic in shape; placing the large NCM particles and the glass phase material simultaneously into a first mixer, and stirring them thoroughly to ensure uniform mixing; 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: Subsequently, performing oxygen-induced sintering on the stirred large NCM particles and the glass phase material; after sintering, the large NCM particles are coated with a glass phase layer formed by the glass phase material, thus forming a glass phase layer. NCM large particles; wherein the glass phase layer can block the 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; Step 520: Mix 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 in a second mixer and stirred thoroughly to make them uniformly mixed. After stirring, the LLZO fine particles are distributed in the glass phase layer or on the surface of the glass phase layer, and the whole is formed into composite NCM large particles; Step 530: The above-mentioned composite NCM large particles are then subjected to oxygen sintering, and the sintering process is used to eliminate the interface resistance between the LLZO fine particles and the NCM large particles during lithium ion transport; the whole is formed into a plurality of sintered powders.

2. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, wherein the size of a single large NCM particle 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 520, the maximum radial dimension of the fine LLZO particle is less than 40 nanometers.

3. The method for manufacturing NCM cathode particles coated with LLZO and glass phase using a sintering 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 sintering process as described in claim 1, wherein the material of the glass phase is an amorphous oxide or non-oxide solid electrolyte with a lithium-ion conductivity higher than 10⁻⁵ S / cm; it is selected from at least one of the following: lithium oxides of groups IIIA, IVA, and VA; or amorphous oxide solid electrolytes; amorphous perovskite solid electrolytes; garnet solid electrolytes; or lithium-phosphorus-oxynitrides.

5. A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, wherein the glass phase material is an amorphous oxide or non-oxide solid electrolyte with a lithium-ion conductivity higher than 10⁻⁵ S / cm; it 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; LLTO; LLZO; LiPON; at least one of the above.

6. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, wherein in step 510, the sintering temperature is 250°C to 650°C, the temperature is increased by 1.5°C to 5°C per minute, and the temperature is held at the highest temperature for 0.5 hours to 4 hours.

7. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering 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 sintering 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; doping LLZO with copper 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. A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, wherein in a single composite NCM macroparticle, the total weight of all the LLZO fine particles is between 0.2 wt% and 2 wt% of the weight of the NCM macroparticle with the glass phase layer.

10. A method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, wherein in step 520, the rotation speed of the second mixer is 20 rpm to 500 rpm and the stirring time is 2 hours to 12 hours; and in step 530: the sintering temperature is 550°C to 650°C, the temperature is increased at a rate of 1.5 to 5°C / minute, and the temperature is held at the highest temperature for 0.5 hours to 2 hours.

11. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 1, further comprising step 540: mixing the sintered powder, a plurality of CNTs (Carbon Nanotubes) and a 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 sintering process as described in claim 11, wherein the carbon material is mixed by simultaneously placing the sintered powder, the plurality of CNTs, and the plurality of nano-sized amorphous carbons into a dry stirrer for mixing, so that the CNTs and the nano-sized 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 sintering process as described in claim 11, wherein the carbon material is mixed by first mixing the CNT with the sintered powder, and then mixing it with the nano-level amorphous carbon to form the carbon-coated cathode particles; wherein the CNT and the sintered powder are mixed 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 sintering process as described in claim 13, wherein the dry ball milling mixing method involves directly placing the CNT and the sintered powder into a dry ball mill for ball milling, the dry ball mill speed being between 50 rpm and 1000 rpm, the mixing time being between 20 minutes and 12 hours, and the ball milling being performed at room temperature to 50 degrees Celsius; 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.

15. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering process as described in claim 13, wherein the wet ball milling mixing method involves dispersing the CNT in a dispersant and then placing it together with the sintered powder into a wet ball mill for wet ball milling, wherein the 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-scale amorphous carbon is added for mixing, so that the CNT and the nano-scale 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 sintering 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; wherein 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 sintering 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 sintering process as described in claim 11, wherein the total weight of the CNT accounts for a proportion of the weight of a single composite NCM particle between 0.1 wt% and 2 wt%.

19. The method for manufacturing NCM cathode particles coated with LLZO and a glass phase using a sintering 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 sintering 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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