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EP-4741441-A1 - POLYMER AND PREPARATION METHOD THEREFOR, POSITIVE ELECTRODE SHEET, SECONDARY BATTERY, AND ELECTRIC DEVICE

EP4741441A1EP 4741441 A1EP4741441 A1EP 4741441A1EP-4741441-A1

Abstract

Provided in the present application are a polymer, a preparation method therefor, a positive electrode sheet, a secondary battery, and an electrical device. The polymer includes a structure as represented by Formula I. X includes a phosphate group or a phosphite group, R1 and R3 each independently include at least one of a polyether segment, a polyester segment, hydrogen and a hydrocarbon group. At least one of R1 and R3 includes a polyether segment or a polyester segment. R2 includes an organic segment. The polymer provided in the present application can effectively improve the maximum solid content of a positive electrode slurry, shorten the filtering time, improve the production efficiency and quality of the electrode sheet, and also improve the flexibility of the electrode sheet.

Inventors

  • SHI, Hanwen
  • WANG, Zejiang
  • HUANG, JICHUN
  • WANG, Xinghui
  • QING, Yalong

Assignees

  • Contemporary Amperex Technology Co., Limited

Dates

Publication Date
20260513
Application Date
20240524

Claims (20)

  1. A polymer, comprising a structure as represented by Formula I: wherein X comprises a phosphate group or a phosphite group, R 1 and R 3 each independently comprise at least one of a polyether segment, a polyester segment, hydrogen and a hydrocarbon group, and at least one of R 1 and R 3 comprises a polyether segment or a polyester segment; and R 2 comprises an organic segment.
  2. The polymer according to claim 1, wherein the organic segment of R 2 comprises at least one of an amide group, an amino group and an aryl group.
  3. The polymer according to claim 1 or 2, wherein the organic segment of R 2 further comprises a C 2-12 hydrocarbon group.
  4. The polymer according to any one of claims 1 to 3, wherein R 2 comprises a structure as represented by Formula II: wherein R 4 and R 5 are randomly copolymerized, R 4 comprises at least one of a C 2-12 hydrocarbylene group, and a C 3-13 amide group, and R 5 comprises at least one of wherein q1, q2, q3, and q4 each independently comprise any integer between 0 and 4, and R 6 a and R 6 b comprise at least one of hydrogen and a C 1-4 alkyl group, 1≤s≤6, and 1≤t≤10.
  5. The polymer according to any one of claims 1 to 4, wherein R 2 comprises a structure as represented by Formula III: wherein R 6 comprises a C 2-12 hydrocarbylene group, and R 7 comprise at least one of and q5 and q6 each independently comprise any integer between 0 and 4, and 1≤n≤6.
  6. The polymer according to any one of claims 1 to 5, wherein a terminal group of R 2 comprises at least one of -C(O)-NH 2 and -CH 2 -NH 2 .
  7. The polymer according to any one of claims 1 to 6, wherein at least one of R 1 and R 3 comprises a polyether segment, and optionally, each of R 1 and R 3 comprises a polyether segment.
  8. The polymer according to any one of claims 1 to 7, wherein at least one of R 1 and R 3 comprises a polyether segment as represented by Formula IV: wherein EO represents -CH 2 -CH 2 -O-, PO represents -CH(CH 3 )-CH 3 -O-, 4≤m1≤50, and 4≤n1≤50.
  9. The polymer according to any one of claims 1 to 8, wherein a terminal group of the polyether segment comprises an aryl group.
  10. The polymer according to any one of claims 1 to 9, wherein X comprises a phosphate group.
  11. The polymer according to any one of claims 1 to 10, comprising at least one of the following polymers as represented by the following formulas: and wherein at least one of R 1 and R 3 comprises a block copolymer polyether segment as represented by Formula IV: wherein EO represents -CH 2 -CH 2 -O-, PO represents -CH(CH 3 ) -CH 2 -O-, 4≤m1≤50, 4≤n1≤50, and R 6 and R 4 each independently comprise at least one of a C 4-8 alkylene group and a C 4-8 alkenylene group.
  12. The polymer according to claim 11, wherein a terminal group of the polyether segment comprises an aryl group.
  13. The polymer according to any one of claims 1 to 10, wherein the polymer is as represented by the following formula: wherein R 2 comprises at least one of hydrogen, an aryl group, a substituted or unsubstituted alkyl group, and an amino-group-containing or amide-group-containing organic segment, at least one of R 1 and R 3 comprises a block copolymer polyether segment as represented by Formula IV: wherein EO represents -CH 2 -CH 2 -O-, PO represents -CH(CH 3 )-CH 2 -O-, 4≤m1≤50, 4≤n1≤50, and a terminal group of the polyether segment comprises a phenyl group.
  14. The polymer according to any one of claims 1 to 13, wherein a weight-average molecular weight of the polymer is 1,000 to 10,000, and optionally 2,000 to 5,000.
  15. A preparation method for a polymer, comprising: reacting a compound as represented by Formula VI with R 3 OH, R 1 OH, water, and an unsaturated-bond-containing polymerization monomer to prepare a polymer comprising a structure as represented by Formula I: wherein X comprises a phosphate group or a phosphite group, and each of X 1 , X 2 and X 3 comprises halogen; R 1 and R 3 each independently comprise at least one of a polyether segment, a polyester segment, hydrogen and a hydrocarbon group, and at least one of R 1 and R 3 comprises a polyether segment or a polyester segment; and R 2 comprises an organic segment.
  16. The preparation method according to claim 15, comprising the following steps: subjecting the compound as represented by Formula VI and R 3 OH, R 1 OH and water to a first reaction to prepare an intermediate product as represented by Formula VII: and subjecting the intermediate product and a polymerization monomer comprising at least one of unsaturated-bond-containing amide and unsaturated-bond-containing amine to a second reaction to prepare the polymer.
  17. The preparation method according to claim 16, wherein the second reaction specifically comprises the following steps: subjecting the intermediate product and at least one of the unsaturated-bond-containing amide and the unsaturated-bond-containing amine to an addition reaction, and then a substitution reaction with a halogen-substituted organic alcohol; and sequentially cycling the addition reaction and the substitution reaction for many times, and then preparing the polymer, wherein R 2 comprises a structure as represented by Formula III: wherein R 6 comprises a C 2-12 hydrocarbon group, and R 7 comprises at least one of and wherein q5 and q6 each independently comprise any integer between 0 and 4, and 1≤n≤6.
  18. The preparation method according to claim 16, further comprising the following steps: subjecting the intermediate product and (i) at least one of unsaturated-bond-containing amide and unsaturated-bond-containing amine and (ii) at least one of an unsaturated-bond-containing hydrocarbon monomer and a cyclic amide monomer to a third reaction to prepare the polymer, wherein R 2 comprises a structure as represented by Formula II: wherein R 4 and R 5 are randomly copolymerized, R 4 comprises at least one of a C 2-12 hydrocarbon group, and a C 3-13 amide group, and R 5 comprises at least one of and wherein q1, q2, q3, and q4 each independently comprise any integer between 0 and 4, and R 6 a and R 6 b comprise at least one of hydrogen and a C 1-4 alkyl group, 1≤s≤6, and 1≤t≤10.
  19. A preparation method for a polymer, comprising: reacting a compound as represented by Formula VI with a raw material comprising R 3 OH and R 1 OH to prepare a polymer comprising a structure as represented by Formula I: wherein X comprises a phosphate group or a phosphite group, and each of X 1 , X 2 and X 3 comprises halogen; R 1 and R 3 each independently comprise at least one of a polyether segment, a polyester segment, hydrogen and a hydrocarbon group, and at least one of R 1 and R 3 comprises a polyether segment, and a terminal group of at least one of the polyether segments comprises an aryl group; and R 2 comprises an organic segment.
  20. Application of the polymer according to any one of claims 1 to 14 or the polymer prepared by the preparation method according to any one of claims 15 to 19 as a dispersant.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims priority to Chinese Patent Application No. 202310961340.X, filed on August 1, 2023 and entitled "POLYMER, PREPARATION METHOD THEREFOR, POSITIVE ELECTRODE SHEET, SECONDARY BATTERY, AND ELECTRICAL DEVICE", and claims priority to Chinese Patent Application No. 202311098921.1, filed on August 29, 2023 and entitled "POLYMER AND PREPARATION METHOD THEREFOR, POSITIVE ELECTRODE SHEET, SECONDARY BATTERY, AND ELECTRICAL DEVICE", which are incorporated herein by reference in their entireties. TECHNICAL FIELD The present application relates to the technical field of a secondary battery, and particularly relates to a polymer, a preparation method therefor, a positive electrode sheet, a secondary battery, and an electrical device. BACKGROUND In recent years, secondary batteries have been widely applied to energy storage power systems of hydropower, thermal power, wind power and solar power stations, and various fields such as electric power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment and aerospace. An electrode sheet in a secondary battery is generally prepared by coating a slurry including an active material onto a current collector followed by drying. Increasing the solvent content in the slurry and reducing the solid content of the slurry are effective measures for optimizing the dispersion uniformity of the slurry and improving the coating quality of the slurry. However, the slurry with a high solvent content requires long drying time and is high in manufacturing cost. How to improve the solid content of the slurry and ensure the dispersion uniformity of the slurry at the same time to further effectively improve the maximum solid content of the slurry is a technical problem urgently needing to be solved in the art. SUMMARY The present application is provided in view of the foregoing subject. An objective of the present application is to provide a dispersant capable of improving the maximum solid content of a slurry. According to a first aspect of the present application, a polymer is provided, and includes a structure as represented by Formula I: X includes a phosphate group or a phosphite group. R1 and R3 each independently include at least one of a polyether segment, a polyester segment, hydrogen and a hydrocarbon group. At least one of R1 and R3 includes a polyether segment or a polyester segment. R2 includes an organic segment. The polymer can effectively improve the maximum solid content of a positive electrode slurry, shorten the filtering time, improve the production efficiency and quality of an electrode sheet, and also improve the flexibility of the electrode sheet. In any one implementation, the organic segment of R2 includes at least one of an amide group, an amino group and an aryl group. A nitrogen-containing group or the aryl group in the polymer is favorable for improving an anchoring effect between the polymer and a positive electrode active material, so that the polymer is particularly applicable to a carbon-coated positive electrode active material, and the universality of the polymer as a dispersant is further improved. By increasing anchoring sites of the dispersant, the dispersion effect of the polymer is more effectively achieved, thereby further improving the maximum solid content of the slurry, improving the forming quality of the electrode sheet, and achieving cost reduction with efficiency enhancement at the same time. In any one implementation, the organic segment of R2 further includes a C2-12 hydrocarbon group. The inclusion of the C2-12 hydrocarbon group in the polymer is favorable for further improving the anchoring effect of the polymer and the carbon-modified positive electrode active material. The hydrocarbon group forms effective anchoring with carbon on the positive electrode active material, improving the dispersion of anchoring sites of the polymer on the positive electrode active material, thereby further expanding the application range of the polymer dispersant, improving the maximum solid content of the slurry, improving the forming quality of the electrode sheet, and achieving cost reduction with efficiency enhancement at the same time. In any one implementation, R2 includes a structure as represented by Formula II: R4 and R5 are randomly copolymerized. R4 includes at least one of a C2-12 hydrocarbylene group, and a C3-13 amide group. R5 includes at least one of q1, q2, q3, and q4 each independently include any integer between 0 and 4. R6a and R6b include at least one of hydrogen and a C1-4 alkyl group. 1≤s≤6. 1≤t≤10. The organic segment of the above structure can more effectively achieve an anchoring effect through copolymerization of the nitrogen-containing group and the hydrocarbon group, improve the dispersion effect of the polymer, and effectively improve the solid content of the slurry. In any one implementation, R2 includes a structure as represented by Fo