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CN-122000558-A - Electrode material, preparation method thereof, battery cell, battery device and electricity utilization device

CN122000558ACN 122000558 ACN122000558 ACN 122000558ACN-122000558-A

Abstract

The application provides a battery monomer, an electrode material, a preparation method of the electrode material, a battery device and an electric device. The battery monomer comprises an electrode plate and electrolyte, wherein the electrode plate comprises a current collector and an electrode film layer arranged on the current collector, the electrode film layer comprises an electrode material, the electrode material comprises an electrode active material and a modifying group, the modifying group comprises one or more of cyano, phenyl ester and sulfate, and the modifying group is dispersed in the electrode film layer. The modified group is grafted on the surface of the electrode active material, so that the stability of the surface structure of the electrode active material can be effectively improved, the interface film forming effect of the electrode active material and electrolyte is optimized, and the capacity, first effect, cycle performance and high-temperature storage performance of the battery monomer are further improved.

Inventors

  • TAO LEI
  • FAN YAOJIAN
  • Tang Shengyue
  • ZHANG YUXI
  • SUN CHENGDONG

Assignees

  • 宁德时代新能源科技股份有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (18)

  1. 1. The battery monomer comprises an electrode plate and electrolyte, wherein the electrode plate comprises a current collector and an electrode film layer arranged on the current collector, the electrode film layer comprises an electrode material, the electrode material comprises an electrode active material and a modifying group, the modifying group comprises one or more of cyano, phenyl ester and sulfate, and the modifying group is dispersed in the electrode film layer.
  2. 2. The battery cell of claim 1, wherein the electrode tab is a positive electrode tab.
  3. 3. The battery cell according to claim 1 or 2, wherein the electrode active material is a positive electrode active material selected from one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide; Optionally, the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium cobaltate and lithium manganate, and the molar ratio of nickel element in the lithium nickel cobalt manganese oxide to nickel element, manganese element and cobalt element is 50% -95%, and further optionally 80% -95%.
  4. 4. A battery cell according to any one of claims 1 to 3, wherein the mass content of the modifying group in the electrode film layer is 0.05% -2.5%, optionally 0.05% -1%.
  5. 5. The battery cell of any one of claims 1-4, wherein the electrolyte comprises a solvent comprising one or more of ethylene carbonate, diethyl carbonate, dimethyl carbonate, methylethyl carbonate, propylene carbonate, ethyl acetate, fluoroethylene carbonate, and a lithium salt comprising one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium difluorosulfimide, lithium bistrifluorosulfimide, lithium trifluoromethane sulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorodioxaato phosphate, and lithium tetrafluorooxalato phosphate.
  6. 6. An electrode material comprises an electrode active material and a modifying group, wherein the modifying group is grafted on the surface of the electrode active material, and the modifying group comprises one or more of cyano, alkoxy and sulfate.
  7. 7. The electrode material according to claim 6, wherein the electrode active material is a positive electrode active material selected from one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide; optionally the positive electrode active material comprises one or more of lithium nickel cobalt manganese oxide, lithium cobaltate, lithium manganate, and The molar ratio of nickel element in the lithium nickel cobalt manganese oxide to nickel element, manganese element and cobalt element is 50% -95%, and further optionally 80% -95%.
  8. 8. The electrode material of claim 6 or 7, wherein the electrode material further comprises one or more of methyl, methylene.
  9. 9. The electrode material of any one of claims 6 to 8, wherein the mass content of the modifying group in the electrode material is 0.05% -2.5%, optionally 0.05% -1%.
  10. 10. A method of preparing an electrode material, wherein the method of preparing comprises: Mixing materials comprising an electrode active material, a free radical initiator and a slurry solvent to obtain mixed slurry, wherein the free radical initiator comprises a modified group, and the modified group comprises one or more of cyano, phenyl ester and sulfate; Decomposing the free radical initiator in the mixed slurry to obtain a free radical group, wherein the free radical group comprises the modified group, and the free radical group is grafted to the surface of the electrode active material to obtain the electrode material.
  11. 11. The method of claim 10, wherein the slurry solvent comprises one or more of N-methylpyrrolidone, dimethylacetamide, dimethylformamide.
  12. 12. The preparation method according to claim 10 or 11, wherein the radical initiator is decomposed by heat, light or radiation.
  13. 13. The production method according to any one of claims 10 to 12, wherein the radical initiator comprises one or more of azo-type initiator, organic peroxy-type initiator, inorganic peroxy-type initiator; Optionally the azo initiator comprises azo-bis-isoheptanenitrile Azobisisobutyronitrile (AIBN) one or more of azobisisovaleronitrile, azoiso Ding Qingji formamide, and azobicyclohexylcarbonitrile; Optionally, the organic peroxygen initiator comprises one or more of tert-butyl peroxybenzoate and benzoyl peroxide; optionally, the inorganic peroxygen initiator comprises one or more of potassium persulfate and ammonium persulfate.
  14. 14. The preparation method according to claim 13, wherein the radical initiator comprises an azo-based initiator, and the mixed slurry is heated to a radical initiator decomposition temperature to decompose the radical initiator in the mixed slurry; optionally, the mixed slurry is stirred while heating, and further optionally, the stirring speed of the stirring is 1000rpm/min to 2000rpm/min.
  15. 15. The preparation method according to any one of claims 10 to 14, wherein the mass ratio of the free radical initiator to the electrode active material is 0.05:99.95-2.5:97.5, optionally 0.05:99.95-1:99.
  16. 16. The production method according to any one of claims 10 to 15, wherein the electrode active material is a positive electrode active material including one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum oxide; Optionally, the positive electrode active material includes one or more of lithium nickel cobalt manganese oxide, lithium cobaltate and lithium manganate, and the molar ratio of nickel element in the lithium nickel manganese cobalt oxide to nickel element, manganese element and cobalt element is 50% -95%, and further optionally 80% -95%.
  17. 17. A battery device comprising a plurality of battery cells according to any one of claims 1 to 5.
  18. 18. An electrical device comprising a battery cell according to any one of claims 1 to 5, a battery device according to claim 17, the battery cell or the battery device being for storing or providing electrical energy.

Description

Electrode material, preparation method thereof, battery cell, battery device and electricity utilization device Technical Field The application relates to the technical field of batteries, in particular to an electrode material, a preparation method thereof, a battery cell, a battery device and an electric device. Background Along with the popularization and development of new energy vehicles, the development of the lithium ion battery with high energy density to improve the endurance capacity of the whole vehicle is a main development and application direction of the current power battery products. Currently, the main strategies for improving the energy density of the positive electrode material of the lithium ion battery include adopting a positive electrode active material with high working voltage represented by lithium nickel manganese oxide (such as LiNi0.5Mn1.5O4, abbreviated as LNMO) or adopting a positive electrode active material with high capacity represented by nickel-rich oxide (LiNixCoyMnzO 2, x+y+z=1, abbreviated as NCM). Compared with LNMO, NCM has a higher capacity under normal charge and discharge conditions, and is becoming the most promising high energy density lithium ion battery material for practical applications. However, in the working state of the above positive electrode active material, the surface stability of the positive electrode active material particles is poor, especially in a lithium nickel cobalt manganese oxide system with higher nickel content, the positive electrode electrolyte interface CEI film cannot effectively prevent the positive electrode active material particles from contacting with the electrolyte, so that serious side reactions are continuously caused, and the surface active center is corroded. Therefore, an effective technical solution is needed to improve the surface stability of the positive electrode active material particles of the lithium ion battery in the working state, so as to improve the overall electrochemical performance and the cycle performance of the lithium ion battery. Disclosure of Invention The application provides an electrode material, a preparation method thereof, a battery cell, a battery device and an electric device, and improves the surface stability of the electrode material in a working state. The first aspect of the application provides a battery cell comprising an electrode sheet and an electrolyte, wherein the electrode sheet comprises a current collector and an electrode film layer arranged on the current collector, the electrode film layer comprises an electrode material, the electrode material comprises an electrode active material and a modifying group, the modifying group comprises one or more of cyano groups, phenyl ester groups and sulfate groups, and the modifying group is dispersed in the electrode film layer. The modified group is grafted on the surface of the electrode active material, and the modified group exists on the surface of the electrode active material and is more stable relative to physical wrapping, so that the prepared electrode film layer can simultaneously contain the co-existing modified group and the electrode active material. When the battery monomer is in a working state, the modified group can still form stable connection with the surface of the electrode active material by chemical bonding, and is not easy to dissolve in electrolyte and move along with the traditional CEI film. Therefore, the modified group can continuously stabilize the lattice structure of the electrode active material, more active ions can return to the positive electrode in the discharging process, so that the battery monomer can still have higher initial effect even if the content of the electrode active material is reduced due to the inclusion of the modified group, meanwhile, the effect of optimizing the interfacial film formation of the electrode active material and electrolyte can be achieved, on one hand, the modified group can react with PF 6- to inhibit the generation of HF and water, reduce the etching of the surface of the positive electrode active material, improve the stability of a CEI film formed in the circulating process, better exert the effect of the CEI film, and on the other hand, when the modified group has higher oxidation-reduction potential, the ion transmission capability of the interfacial film can be optimized through participation in film formation, so that the capacity, initial effect, cycle performance and high-temperature storage performance of the battery monomer can be improved. In any embodiment of the first aspect, the electrode sheet is a positive electrode sheet. In any embodiment of the first aspect, the electrode active material is a positive electrode active material selected from one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt aluminum