CN-121983536-A - Method for manufacturing positive electrode particles coated with ceramic particles and glass phase continuous layer by using wet primary sintering process

Abstract

The invention discloses a method for manufacturing positive electrode particles coated with ceramic particles and a glass phase continuous layer by a wet-type primary sintering process, which comprises the following steps of putting a lithium source, a glass phase precursor, an LLZO precursor and a dispersion liquid into a mixer for mixed grinding to form a first precursor slurry, putting a nickel-cobalt-manganese precursor into the first precursor slurry, and fully stirring and mixing to form a second precursor slurry; the second precursor slurry is fully stirred and mixed and then dried to obtain precursor powder, the precursor powder is subjected to aerobic sintering, wherein the lithium source is firstly melted and reacts with each nickel cobalt manganese precursor and each LLZO precursor to form a plurality of NCM (nickel cobalt lithium manganate) particles and a plurality of LLZO particles respectively, the glass phase precursor forms a glass phase layer to cover the outer surface of each NCM particle, and the plurality of LLZO particles are distributed in each glass phase layer to integrally form the plurality of positive electrode particles.

Inventors

• LUO ZHIFENG

Assignees

• 深圳同兴达科技股份有限公司

Dates

Publication Date

20260505

Application Date

20251231

Priority Date

20250103

Claims (20)

1. 1. A method of manufacturing a positive electrode particle coated with a continuous layer of ceramic particles and a glass phase using a wet primary sintering process, wherein the positive electrode particle is used for a positive electrode of a solid state or solid-like battery, the method comprising the steps of: Step A, a lithium source, a glass phase precursor, an LLZO precursor and a dispersion liquid are placed into a mixer to be mixed and ground to form first precursor slurry, and the particle size of the first precursor slurry is ground to be D50 particle size smaller than 200nm, wherein the glass phase precursor is a precursor for forming a glass phase layer, the LLZO precursor is a precursor for forming LLZO, and the LLZO is used for forming the ceramic particles, and the LLZO is a lithium lanthanum zirconium oxide compound; Adding a nickel-cobalt-manganese precursor into the first precursor slurry of the mixer, and fully stirring and mixing to form a second precursor slurry, wherein the nickel-cobalt-manganese precursor is a precursor for forming NCM (non-uniform metal oxide), the nickel-cobalt-manganese precursor is a granular material formed by a plurality of grains, and the grain surface of the nickel-cobalt-manganese precursor is provided with a plurality of holes, wherein NCM is nickel-cobalt lithium manganate; drying the second precursor slurry to obtain precursor powder, wherein the precursor powder is dried by one of vacuum baking, reduced pressure concentration and spray drying to rapidly remove liquid, so that the glassy precursor and the LLZO precursor are separated out from the particle surfaces of the nickel cobalt manganese precursor to form a deposition layer, and the deposition layer is deposited on the particle surfaces of the nickel cobalt manganese precursor to generate precursor powder with uniform and compact deposition layer; Wherein the distribution pattern of the glassy precursor and the LLZO precursor on the particle surface of the nickel cobalt manganese precursor is a continuous film distribution pattern or a discontinuous distribution pattern with island particles; Step D, placing the precursor powder into a sintering furnace for aerobic sintering to obtain sintered powder formed by a plurality of positive electrode particles, wherein the melting point of the lithium source is lower than that of the nickel cobalt manganese precursor, the glass phase precursor and the LLZO precursor, so that the lithium source can be firstly melted in the high temperature of the aerobic sintering to be mixed into the deposition layer of the precursor powder and enter the holes of the nickel cobalt manganese precursor, then the lithium source can be decomposed into highly reactive lithium oxide which reacts with the nickel cobalt manganese precursor to form a plurality of NCM particles, and meanwhile, the lithium oxide also reacts with the LLZO precursor to form a plurality of LLZO particles; The glass phase layer is used for preventing the NCM particles from being in direct contact with electrolyte, reducing interface side reaction, reducing interface impedance of lithium ions entering and exiting the NCM particles, improving rate charge and discharge performance and accommodating volume change of charge and discharge.
2. 2. The method for manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 1, wherein in the first precursor slurry, the solid matters formed by the lithium source, the glass phase precursor and the LLZO precursor account for 5wt% to 25wt% of the first precursor slurry; in the second precursor slurry, the solid matters formed by the lithium source, the glass phase precursor, the LLZO precursor and the nickel cobalt manganese precursor account for 15-40 wt% of the second precursor slurry, and Wherein the ratio of the weight of the nickel cobalt manganese precursor to the total weight of the glassy precursor and the LLZO precursor is greater than 20:1.
3. 3. The method for manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 1, wherein the dispersion is an alcoholic solution or pure water.
4. 4. The method of claim 1, wherein a buffer solution is further added in step C to control the thickness and density of the deposited layer formed by the vitreous phase precursor and the LLZO precursor.
5. 5. The method for manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 4, wherein the buffer is ammonia or acetic acid.
6. 6. The method of claim 1, wherein the molar equivalent ratio of the nickel cobalt manganese precursor, the lithium source, the glass phase precursor, and the LLZO precursor in the second precursor slurry is 1.0 (1.02-1.25): (0.005-0.02).
7. 7. The method of claim 1, wherein the nickel cobalt manganese precursor has a particle size of 1 to 5 microns, and wherein the LLZO precursor has a particle size of 20nm to 200nm.
8. 8. The method for producing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 1, wherein the nickel cobalt manganese precursor is a porous spherical nickel cobalt manganese precursor composed of needle-like crystal grains.
9. 9. The method for manufacturing a positive electrode particle coated with a continuous layer of ceramic particles and glass phase using a wet primary sintering process as claimed in claim 1, wherein the nickel cobalt manganese precursor is Ni x Mn y Co z (OH) 2 , x >0.8, x+y+z=1.
10. 10. The method of manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 1, wherein the lithium source is selected from at least one of lithium hydroxide, lithium carbonate, lithium nitrate, or a mixture thereof.
11. 11. The method of claim 1, wherein the glass phase precursor is an amorphous oxide having a lithium ion conductivity of greater than 10 -5 S/cm after heat treatment, and wherein the glass phase layer has a crystal structure that does not have a specific morphology, and wherein the glass phase layer is a continuous film layer coated on the outer surface of the NCM particles.
12. 12. The method of claim 11, wherein the non-crystalline oxide or non-oxide solid electrolyte is an oxide of lithium and a group IIIA, IVA, VA element.
13. 13. The method of claim 12, wherein the oxide of lithium and IIIA, IVA, VA group element is Li 2 O-RO n , wherein R is at least one of boron, aluminum, silicon, germanium, phosphorus, and arsenic, and n=1 to 3.
14. 14. The method of manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase using a wet primary sintering process according to claim 11, wherein the amorphous oxide is an amorphous oxide-based solid electrolyte.
15. 15. The method of claim 14, wherein the amorphous oxide-based solid electrolyte is at least one selected from the group consisting of an amorphous perovskite-based solid electrolyte, a garnet-based solid electrolyte, a lithium-phosphorus-oxy-nitride, and lithium aluminum titanium phosphate, wherein lithium-phosphorus-oxy-nitride is abbreviated as LiPON, and lithium aluminum titanium phosphate is abbreviated as LATP.
16. 16. The method of claim 1, wherein the LLZO precursor is a specific component of the electrolyte of Granati Dan Gutai forming a cubic system by co-firing with the lithium source, the specific component comprises at least one of an oxide, a hydroxide, and a carbonate, and an intermediate product formed by co-precipitation or sintering of the specific component is an amorphous structure having a distinct crystalline phase or a multi-component mixed structure.
17. 17. The method of claim 16, wherein the garnet Dan Gutai electrolyte is Li 7 La 3 Zr 2 O 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.
18. 18. The method of claim 16, wherein the LLZO precursor further comprises a doping element of at least one of aluminum, gallium, tantalum, niobium, copper.
19. 19. The method for manufacturing the positive electrode particles coated with the ceramic particles and the continuous layer of glass phase by using the wet-type primary sintering process according to claim 1, wherein in the aerobic sintering of the step D, the temperature is raised to 400 ℃ to 700 ℃ and maintained for 1 to 4 hours in advance of pure oxygen atmosphere, so that the lithium source is completely melted and fully mixed with other substances in the precursor powder, and then raised to 800 ℃ to 1000 ℃ and maintained for 6 to 12 hours, and finally naturally cooled to room temperature in pure oxygen atmosphere.
20. 20. The method for producing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase by a wet primary sintering process according to claim 1, further comprising the step E of mechanically pulverizing the sintered powder and sieving the powder with a sieve.

Description

Method for manufacturing positive electrode particles coated with ceramic particles and glass phase continuous layer by using wet primary sintering process Technical Field The invention relates to the technical field of positive electrode materials, in particular to a method for manufacturing positive electrode particles coated with ceramic particles and a glass phase continuous layer by a wet one-time sintering process. Background The battery is mainly formed by a positive electrode and a negative electrode which are arranged in an electrolyte, wherein the positive electrode is formed by mixing and dispersing a plurality of positive electrode conductive units (positive electrode materials such as lithium cobaltate) in slurry. To increase conductivity, the positive electrode slurry is filled with a plurality of positive electrode particles, and the material of the positive electrode particles may be selected from NCM (lithium nickel cobalt manganese) or a mixture having NCM. However, the conventional technique is poor in overall battery performance because the cathode particles have a low electron conductivity and a low lifetime due to side reactions at the interface of the cathode particles. Therefore, the prior art has coated ceramic particles such as LLZO (lithium lanthanum zirconium oxide) on the outside of the positive electrode particles to increase the conductivity to lithium ions, and coated glass phase layers on the surface of the positive electrode particles to reduce interfacial resistance, improve powder coating property and stabilize it in electrolyte to prevent interfacial side reactions. In order to further increase the conductivity of the slurry, carbon nanotubes and nano-sized amorphous carbon may be added to coat the positive electrode particles. The prior art method for producing NCM composite positive electrode particles coated with ceramic particles and a glass phase layer employs a two-stage sintering step in which NCM particles and ceramic particles are preformed, respectively, using precursors. Then sintering the NCM particles and the glass phase material to coat a glass phase layer on the surface of the NCM particles, and mixing and stirring the ceramic particles and the NCM particles with the glass phase layer to form the composite anode particles. However, this method requires two-stage sintering, which requires a lot of cost and time, resulting in an increase in manufacturing cost. Accordingly, the prior art has drawbacks and needs improvement. Disclosure of Invention The invention aims to solve the technical problem of providing a method for manufacturing positive electrode particles coated with ceramic particles and a glass phase continuous layer by applying a wet one-time sintering process, wherein the positive electrode particles coated with the glass phase and the ceramic particles are formed by wet one-time sintering, so that the production efficiency is improved, and the time cost is reduced. Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method for manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase by a wet-type primary sintering process, which adopts a wet-type mixing method, i.e. by adding a dispersion liquid, the lithium source, the glass phase precursor, the LLZO precursor and the nickel cobalt manganese precursor are uniformly dispersed in a solution, so that the overall uniformity is better, and the deposition layer formed by depositing the glass phase precursor and the LLZO precursor on the surface of the nickel cobalt manganese precursor is more compact, so that the glass phase layer and the LLZO particles with more complete coating property can be formed. The glassy phase layer can block direct contact between the NCM particles and the electrolyte, reduce interfacial side reactions, and reduce interfacial resistance of lithium ions entering and exiting the NCM particles. The LLZO particles have the capability of containing and equalizing lithium ions, and can disperse the paths of the lithium ions, so that the lithium ions have better paths. The NCM precursor, the glassy phase precursor and the LLZO precursor can be formed into the positive electrode particles by applying the one-time sintering process, so that the complexity of the process, the operation time and the production cost can be reduced. The outside of the positive electrode particles is further coated with the carbon nano tube and the nano-scale amorphous carbon, so that the conduction efficiency of electrons on the positive electrode particles can be increased. The positive electrode with the positive electrode particles can be used as a ternary cathode (ternary cathode). In order to achieve the above object, a method for manufacturing a positive electrode particle coated with ceramic particles and a continuous layer of glass phase by wet primary sintering process i