Search

CN-121983547-A - High-nickel ternary positive electrode material and preparation method and application thereof

CN121983547ACN 121983547 ACN121983547 ACN 121983547ACN-121983547-A

Abstract

The invention discloses a high-nickel ternary cathode material and a preparation method and application thereof, which belong to the technical field of batteries and battery materials, wherein a coating layer is formed on the surface of the high-nickel ternary cathode material through silicon dioxide, so that the direct contact between an electrode material and electrolyte is effectively isolated, then graphene/titanium dioxide core-shell whisker is used as a reinforcing phase to be coated on the surface of the silicon dioxide coating layer again through a sulfhydryl-alkene clicking reaction, the interfacial binding force between the two coating layers is increased, the volume change caused by lithium ion intercalation and deintercalation can be dealt with, the structural stability of the material is maintained, and the specific discharge capacity, the capacity retention rate and the cycling stability are improved; according to the graphene/titanium dioxide core-shell whisker, titanium dioxide containing whisker is synthesized on the surface of graphene containing a lamellar structure through microwave heating, the titanium dioxide is taken as a core layer, then a lanthanum metal skeleton with a lamellar structure is synthesized through hydrothermal synthesis, and the interface binding force can be further improved through a mechanical interlocking effect.

Inventors

  • WANG FENG
  • ZHENG XIYAN
  • HUANG XIAOFENG
  • DENG JIANQIU
  • LIU PENG
  • LIU DAOCHENG
  • LIU JIAGENG

Assignees

  • 桂林电子科技大学

Dates

Publication Date
20260505
Application Date
20260203

Claims (10)

  1. 1. The preparation method of the high-nickel ternary cathode material is characterized by comprising the following steps of: Step one, generating ethylene glycol titanium white flocculation precipitation through hydrolysis of tetraisopropyl phthalate, then utilizing a microwave heating method to promote the white flocculation precipitation to grow directionally along the surface of graphene to form a graphene/titanium dioxide whisker precursor, and then calcining to obtain the graphene/titanium dioxide whisker; secondly, growing a lanthanum metal framework on the surface of the graphene/titanium dioxide whisker by carrying out hydrothermal coordination on metal lanthanum and 4-vinylbenzoic acid to obtain the graphene/titanium dioxide core-shell whisker; Generating silicon dioxide on the surface of LiNi 0.9 Co 0.05 Mn 0.05 O 2 by a sol-gel method to obtain a silicon dioxide coated high-nickel material, and condensing hydroxyl on the surface of the silicon dioxide coated high-nickel material with gamma-mercaptopropyl trimethoxysilane to prepare a mercapto silicon dioxide coated high-nickel material; and fourthly, carrying out a sulfhydryl-alkene clicking reaction on the high-nickel material coated by the sulfhydryl silicon dioxide and the graphene/titanium dioxide core-shell whisker under the action of an initiator 2, 2-dimethylolpropionic acid to obtain the high-nickel ternary anode material.
  2. 2. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the specific preparation steps of the graphene/titanium dioxide whisker precursor are as follows: Adding ethylene glycol and graphene dispersion liquid with the concentration of 2mg/mL into a reaction kettle, introducing nitrogen to remove air in the reaction kettle, then adding tetraisopropyl phthalate, stirring for 10-12min at 20-25 ℃ and 500-600r/min, then placing in a microwave heating device, heating for 2-3min at 700W and 2.45GHz, hydrolyzing the tetraisopropyl phthalate to generate ethylene glycol titanium white flocculation precipitation, carrying out suction filtration, washing a filter cake with deionized water and ethanol for 2-4 times respectively, and carrying out vacuum drying at 60-70 ℃ for 1-2h to obtain a graphene/titanium dioxide whisker precursor; The dosage ratio of the ethylene glycol to the graphene dispersion liquid to the tetraisopropyl phthalate is 1000-1200mL, 200-300mL and 20-30mL.
  3. 3. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the specific preparation steps of the graphene/titanium dioxide whisker are as follows: And (3) placing the graphene/titanium dioxide whisker precursor in a muffle furnace, heating to 500-520 ℃ under the conditions of nitrogen protection and heating speed of 10-12 ℃ per minute, and preserving heat for 2-3 hours to obtain the graphene/titanium dioxide whisker.
  4. 4. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the specific preparation steps of the graphene/titanium dioxide core-shell whisker are as follows: Adding lanthanum nitrate, 4-vinyl benzoic acid and N, N-dimethylformamide into a reaction kettle, stirring for 10-12min at 20-25 ℃ and 500-600r/min, adding deionized water and graphene/titanium dioxide whiskers, heating to 70-75 ℃, standing for 24-26h, naturally cooling to room temperature, centrifuging for 3-5min at 8000-8500r/min, filtering, washing the precipitate with methanol for 2-4 times, exchanging solvent with chloroform, continuously soaking for 24-26h at 20-25 ℃, and vacuum drying for 1-2h at 60-70 ℃ to obtain graphene/titanium dioxide core-shell whiskers.
  5. 5. The method for preparing the high-nickel ternary cathode material according to claim 4, wherein the dosage ratio of lanthanum nitrate, 4-vinylbenzoic acid, N-dimethylformamide, deionized water, graphene/titanium dioxide whiskers, methanol and chloroform is 15-20 g/5-7 g/550-650 mL/250-270 mL/20-22 g/500-600 mL.
  6. 6. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the specific preparation steps of the silicon dioxide coated high-nickel material are as follows: Adding LiNi 0.9 Co 0.05 Mn 0.05 O 2 and deionized water into a reaction kettle, stirring for 10-12min at 20-25 ℃ and 500-600r/min, then adding tetraethoxysilane and ethanol, heating to 50-60 ℃, continuously stirring for 1-2h, heating again to 80-85 ℃, continuously stirring until the ethanol is completely evaporated, filtering, washing a filter cake with deionized water for 2-4 times, and vacuum drying at 60-70 ℃ for 1-2h to obtain a silicon dioxide coated high nickel material; The dosage ratio of the LiNi 0.9 Co 0.05 Mn 0.05 O 2 to the deionized water to the ethyl orthosilicate to the ethanol is 60-70g to 250-300mL to 4-5g to 300-400mL.
  7. 7. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the preparation method of the mercapto silica coated high-nickel material comprises the following specific steps: Adding a silicon dioxide coated high nickel material, ethanol and deionized water into a reaction kettle, stirring for 10-12min at 20-25 ℃ and 500-600r/min, then adjusting the pH value to 4-5 by using hydrochloric acid, adding gamma-mercaptopropyl trimethoxysilane, heating to 80-90 ℃, continuously stirring for 12-14h, centrifuging for 3-5min at 8000-8500r/min, filtering, washing the precipitate with deionized water and absolute ethanol for 2-4 times respectively, and vacuum drying for 1-2h at 60-70 ℃ to obtain a thiolated silicon dioxide coated high nickel material; The dosage ratio of the silicon dioxide coated high nickel material, ethanol, deionized water and gamma-mercaptopropyl trimethoxysilane is 50-60g:2-3L:1-1.2L:200-300mL.
  8. 8. The preparation method of the high-nickel ternary cathode material according to claim 1, wherein the specific preparation steps of the high-nickel ternary cathode material are as follows: Adding a thiolated silicon dioxide coated high-nickel material, graphene/titanium dioxide core-shell whisker, 2-dimethylolpropionic acid and tetrahydrofuran into a reaction kettle, stirring for 10-12min at 20-25 ℃ and 500-600r/min, solidifying for 6-7h at a wavelength of 365nm and an optical intensity of 6mW/cm, filtering, washing the precipitate with deionized water and absolute ethyl alcohol for 2-4 times respectively, and vacuum drying for 1-2h at 60-70 ℃ to obtain a high-nickel ternary anode material; the mercapto silicon dioxide coated high nickel material, the graphene/titanium dioxide core-shell whisker, the 2, 2-dimethylolpropionic acid and the tetrahydrofuran are in a dosage ratio of 10-20g to 5-7g to 0.8-0.9g to 500-600mL.
  9. 9. A high nickel ternary cathode material prepared by the preparation method of any one of claims 1-8.
  10. 10. The use of a high nickel ternary cathode material according to claim 9 in lithium batteries.

Description

High-nickel ternary positive electrode material and preparation method and application thereof Technical Field The invention belongs to the technical field of batteries and battery materials, and particularly relates to a high-nickel ternary positive electrode material, a preparation method and application thereof. Background High nickel layered cathode materials have attracted considerable attention with higher specific capacity, battery energy density and low cost advantages. However, as the nickel content increases, the preparation and storage of the material become complicated, and the charge-discharge cycle performance and thermal stability are reduced, thereby affecting the cycle life and safety of the battery. The adverse factors affecting the application of the high nickel layered cathode material are mainly surface pH and electrode/electrolyte interface stability. Firstly, the higher pH value of the material surface is easy to react with water and carbon dioxide in the air in the storage process, firstly, the gas expansion is caused in the battery circulation process, and secondly, the loss of the electrode paste water-absorbing gel is easy to cause. Secondly, the electrode/electrolyte interface of the ternary material is unstable, and particularly transition metal at the surface interface is easy to dissolve to generate phase change, so that positive electrode cycle attenuation is caused. The high-nickel layered anode material is an excellent anode material, and has been applied to market due to the advantages of high capacity, good rate capability and the like, but the poor cycle performance of NCM seriously hinders the further application to market. Research shows that the coating technology is an effective means for improving the circulating performance of NCM. Low cost, high performance cladding materials are of particular interest. The solid electrolyte has attracted attention because of its good lithium ion diffusion coefficient, excellent thermal stability and structural stability, such as the solid electrolyte Li 4SiO4, which can be used as a positive electrode material. The Chinese patent application with publication number of CN119911987A discloses a high-nickel ternary positive electrode material coated by a silicon-containing electrolyte, a preparation method thereof and a battery, wherein in the scheme, when a precursor of the high-nickel ternary positive electrode material is coated, graphene modified titanium dioxide powder is added into an tetraethoxysilane solution to provide a certain structural support for the positive electrode material, and in the process of lithium ion intercalation/deintercalation, stress generated by volume change is partially buffered by a titanium dioxide and graphene composite structure, so that pulverization and structural damage of the high-nickel ternary positive electrode material are reduced, but the graphene modified titanium dioxide in the scheme is coated on a silicon dioxide layer only through physical stirring, so that good interface combination cannot be formed, and the graphene modified titanium dioxide layer is easy to fall off when the volume is expanded. Disclosure of Invention The invention aims to provide a high-nickel ternary cathode material, a preparation method and application thereof, wherein a coating layer is formed on the surface of the high-nickel ternary cathode material through silicon dioxide, so that the electrode material is effectively isolated from direct contact with electrolyte, then graphene/titanium dioxide core-shell whisker is used as a reinforcing phase to be coated on the surface of the silicon dioxide coating layer again through a sulfhydryl-alkene clicking reaction, the interfacial binding force between the two coating layers is increased, the volume change caused by lithium ion intercalation and deintercalation can be dealt with, the structural stability of the material is maintained, and the discharge specific capacity, the capacity retention rate and the cycle stability are improved. The aim of the invention can be achieved by the following technical scheme: A preparation method of a high-nickel ternary cathode material comprises the following steps: Step one, generating ethylene glycol titanium white flocculation precipitation through hydrolysis of tetraisopropyl phthalate, then utilizing a microwave heating method to promote the white flocculation precipitation to grow directionally along the surface of graphene to form a graphene/titanium dioxide whisker precursor, and then calcining to obtain the graphene/titanium dioxide whisker. And secondly, growing a lanthanum metal framework on the surface of the graphene/titanium dioxide whisker by carrying out hydrothermal coordination on metal lanthanum and 4-vinylbenzoic acid to obtain the graphene/titanium dioxide core-shell whisker. And thirdly, generating silicon dioxide on the surface of the LiNi 0.9Co0.05Mn0.05O2 by a sol-gel method to obtain a silicon dioxi