Method for preparing lithium ion battery mixed positive electrode

Abstract

The invention provides a method for preparing a lithium ion battery mixed positive electrode. Slurries comprise different proportions of a first active material, a second active material and a third active material, wherein the molecular formula of the first active material is LiNi0.8Mn0.1Co0.1O2, the molecular formula of the second active material is LiNi0.3Mn0.4Co0.3O2, and the molecular formulaof the third active material is LiMnPO4, and particles with two particle sizes exist in the first active material; the average particle size of the second active material is 50-200 nm, the length-to-diameter ratio of the second active material is 1.1-1.3, and the D90 / D10 value of the second active material is 1.6-2.2; and the average particle size of the third active material is 0.5-1 [mu]m, thelength-to-diameter ratio of the third active material is 1.5-2, and the D90 / D10 value of the third active material is 1.2-1.5. The slurries are respectively prepared according to the different structures of the active materials, a current collector is respectively coated with the slurries to sequentially obtain a first active material layer, a first active material and second active material mixedlayer and a third active material layer along a direction from a position adjacent to the current collector to a position away from the current collector. The slurries obtained in the invention havegood dispersibility and good retention performances, and the positive electrode has good high-rate performances and a high energy density.

Description

technical field

[0001] The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of a lithium ion battery mixed positive electrode. Background technique

[0002] With the gradual increase in the energy density, output power and cycle life requirements of electric tools for batteries, the positive electrode composed of a single active material can no longer meet the needs of electric tools, and batteries with mixed positive electrode materials have become the focus of research and development. , different mixing technologies and different structural designs for active materials are required. Although the current mixed materials can provide high output power and energy density, the internal resistance of the pole piece is biased due to excessive compression of the pole piece. Large, the heat release is obvious at high rates, and the cycle life of the battery is deteriorated due to the dissolution of the transition metal Ni. ...

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