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EP-4742354-A1 - ELECTROLYTE, BATTERY, AND ELECTRIC DEVICE

EP4742354A1EP 4742354 A1EP4742354 A1EP 4742354A1EP-4742354-A1

Abstract

An electrolyte, a battery, and an electric device are provided, where the electrolyte includes: A x O y Z- and PO 2 F 2 - , where A includes at least one of P, S, or Si, 1≤x≤2, 4≤y≤5, and 2≤z≤3.

Inventors

  • WU, Zeli
  • HAN, CHANGLONG
  • JIANG, BIN
  • GUO, Jie
  • WU, QIAO
  • LIU, WENHAO
  • HUANG, LEI

Assignees

  • Contemporary Amperex Technology Co., Limited

Dates

Publication Date
20260513
Application Date
20230829

Claims (20)

  1. An electrolyte, comprising: A x O y Z- and PO 2 F 2 - , wherein A comprises at least one of P, S, or Si, 1≤x≤2, 4≤y≤5, and 2≤z≤3.
  2. The electrolyte according to claim 1, wherein A x O y Z- comprises at least one of PO 4 3- , SO 4 2- , or Si 2 O 5 2- .
  3. The electrolyte according to claim 1 or 2, wherein A x O y Z- comprises PO 4 3- .
  4. The electrolyte according to any one of claims 1 to 3, wherein based on a total mass of the electrolyte, a total mass concentration of A x O y Z- and PO 2 F 2 - is less than or equal to 2000 ppm.
  5. The electrolyte according to any one of claims 1 to 4, wherein based on the total mass of the electrolyte, the total mass concentration of A x O y Z- and PO 2 F 2 - is less than or equal to 1500 ppm.
  6. The electrolyte according to any one of claims 1 to 5, wherein based on the total mass of the electrolyte, a mass concentration of A x O y Z- is m, a mass concentration of PO 2 F 2 - is n, and n/m=(10-1000):1.
  7. The electrolyte according to claim 6, wherein n/m=(100-500):1.
  8. The electrolyte according to claim 6 or 7, wherein based on the total mass of the electrolyte, the mass concentration m of A x O y Z- is 1 ppm-1000 ppm.
  9. The electrolyte according to any one of claims 6 to 8, wherein based on the total mass of the electrolyte, the mass concentration m of A x O y Z- is 1 ppm-200 ppm.
  10. The electrolyte according to any one of claims 6 to 9, wherein based on the total mass of the electrolyte, the mass concentration n of PO 2 F 2 - is 1 ppm-1000 ppm.
  11. The electrolyte according to any one of claims 6 to 10, wherein based on the total mass of the electrolyte, the mass concentration n of PO 2 F 2 - is 1 ppm-200 ppm.
  12. The electrolyte according to any one of claims 6 to 11, wherein the electrolyte further comprises a film-forming additive.
  13. The electrolyte according to claim 12, wherein based on the total mass of the electrolyte, a mass concentration of the film-forming additive is w, and (m+n)/w is 1:(10-100).
  14. The electrolyte according to claim 13, wherein (m+n)/w is 1:(20-80).
  15. The electrolyte according to claim 13 or 14, wherein the mass concentration w of the film-forming additive is 0.2%-0.5%.
  16. The electrolyte according to any one of claims 13 to 15, wherein the mass concentration w of the film-forming additive is 0.25%-0.45%.
  17. The electrolyte according to any one of claims 12 to 16, wherein the film-forming additive comprises at least one of tris(trimethylsilyl) phosphate, tris(trimethylsilyl) borate, or tris(trimethylsilyl) phosphite.
  18. A battery, comprising the electrolyte according to any one of claims 1 to 17.
  19. The battery according to claim 18, wherein the battery comprises a lithium-ion battery.
  20. The battery according to claim 18 or 19, wherein the battery comprises a positive electrode plate, and a positive electrode active material of the positive electrode plate satisfies at least one of the following conditions: a volume-based median particle size D v 50 of the positive electrode active material is 1 µm-4 µm; a BET specific surface area of the positive electrode active material is 1 m 2 /g-4 m 2 /g; and a compacted density of the positive electrode active material under a pressure of 300 MPa is 3.2 g/cm 3 -3.8 g/cm 3 .

Description

TECHNICAL FIELD This application pertains to the field of secondary battery technologies and specifically relates to an electrolyte, a battery, and an electric device. BACKGROUND Lithium-ion batteries have been not only used in energy storage power supply systems such as hydroelectric power plants, thermal power plants, wind power plants, and solar power plants, but also widely used in many other fields including electric transportation tools such as electric bicycles, electric motorcycles, and electric vehicles, military equipment, and aerospace. With continuous charge and discharge cycles, the DCR (direct current resistance) of the existing lithium-ion batteries continuously increases, thus affecting the power performance of the batteries. SUMMARY In view of the technical problems existing in the background, this application provides an electrolyte, with an objective to reduce a DCR growth rate of a lithium-ion battery including the electrolyte during charge and discharge cycles, thereby improving the power performance of the lithium-ion battery. To achieve the above objective, a first aspect of this application provides an electrolyte, where the electrolyte includes: AxOyZ- and PO2F2-, where A includes at least one of P, S, or Si, 1≤x≤2, 4≤y≤5, and 2≤z≤3. The electrolyte composed according to this application can effectively reduce a DCR growth rate of a battery including the electrolyte during charge and discharge cycles, thereby improving the power performance of the lithium-ion battery. In some embodiments of this application, AxOyZ- includes at least one of PO43-, SO42-, or Si2O52-, optionally including PO43-. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, based on a total mass of the electrolyte, a total mass concentration of AxOyZ- and PO2F2- is less than or equal to 2000 ppm, optionally less than or equal to 1500 ppm. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, based on the total mass of the electrolyte, a mass concentration of AxOyz- is m, a mass concentration of PO2F2- is n, and n/m=(10-1000):1, optionally (100-500):1. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, based on the total mass of the electrolyte, the mass concentration m of AxOyZ- is 1 ppm-1000 ppm, optionally 1 ppm-200 ppm. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, based on the total mass of the electrolyte, the mass concentration n of PO2F2- is 1 ppm-1000 ppm, optionally 1 ppm-200 ppm. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, the electrolyte further includes a film-forming additive. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, based on the total mass of the electrolyte, a mass concentration of the film-forming additive is w, and (m+n)/w is 1:(10-100), optionally 1:(20-80). This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, the mass concentration w of the film-forming additive is 0.2%-0.5%, optionally 0.25%-0.45%. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. In some embodiments of this application, the film-forming additive includes at least one of tris(trimethylsilyl) phosphate, tris(trimethylsilyl) borate, or tris(trimethylsilyl) phosphite. This can reduce the DCR growth rate of the lithium-ion battery including the electrolyte during charge and discharge cycles. A second aspect of this application provides a battery including the electrolyte according to the first aspect of this application. This allows the battery to have excellent power performance. In some embodiments of this application, the battery includes a positive electrode plate, where the positive electrode active material of the positive electrode plate satisfies at least one of the following conditions: a volume-based median particle size Dv50 of the positive electrode active material is 1 µm-4 µm, optionally 1 µm-3 µm;a BET specific surface area of the positive electrode active material is 1 m2/g-4 m2/g, optionally 1 m2/g-3 m2/g; anda compacted density of the positive electrode active material under a pressure of 300 MPa is 3.2 g/cm3-3.8 g/cm3, optionally 3.3 g/cm3-3.6 g/cm3. In some embodiments of this application, the battery includes a negative electrode p