Composite binder for high-nickel ternary material, positive electrode paste, and preparation methods thereof

Abstract

The invention discloses a composite binder for a high-nickel ternary material. The composite binder comprises 20-35 weight percent of suspending polymerized PVDF and 65-80 weight percent of emulsion-polymerized PVDF. The invention further discloses a preparation method of the composite binder for the high-nickel ternary material. The invention further discloses a positive electrode paste containing the composite binder for the high-nickel ternary material and a corresponding preparation method. Through adoption of the composite binder for the high-nickel ternary material, the positive electrode paste, and the preparation methods thereof, defects that NCA particles have a wide particle size distribution range and are easy to absorb water are overcome, bad effects caused by water absorption of the oxidized NCA material are minimized, the overall performance of the positive electrode piece finally obtained is improved substantially, products of the cell manufacture enjoy a brighter market application prospect, the cell can be manufactured extensively, and production and practice significance is delivered.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a composite binder for high-nickel ternary materials, positive electrode slurry and a preparation method thereof. Background technique [0002] At present, lithium-ion batteries have high specific energy and good cycle performance, and are environmentally friendly, and have become an indispensable new power source in the field of power battery vehicles. Nickel cobalt aluminum oxide (LiNi 0.8 co 0.15 al 0.05 o 2 , NCA) materials have become a research hotspot because of their higher specific capacity and energy density, especially their advantages in the cruising range of electric vehicles. [0003] At present, there are many problems in the practical application of NCA materials. Due to its complex manufacturing process, high residual alkali content on the surface of the particles, and easy water absorption, NCA material has poor compatibility with the existing binder poly...

AI Technical Summary

Problems solved by technology

At present, there are two types of mature and cost-effective PVDF binders for lithium-ion power batteries. The first is suspension-polymerized PVDF. Better, but the slurry is difficult to disperse, the mixing time is long, the internal resistance of the pole piece is large, and the rebound is large

The second is emulsion polymerized PVDF, which has small particles, small molecular weight, good processability, easy dispersion, high compaction density of pole pieces, small rebound, good flexibility, but poor adhesion

[0005] Therefore, there is an urgent need to develop a binder that can effectively solve the shortcomings of NCA particles such as wide particle size distribution and easy water absorption, minimize the adverse effects caused by NCA materials that are easy to absorb water, and significantly improve the quality of the final prepared positive electrode. overall performance of the tablet

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