Cobalt-free positive electrode material, preparation method and application thereof

Abstract

The invention provides a cobalt-free positive electrode material, a preparation method and application thereof. The cobalt-free positive electrode material comprises a cobalt-free base material and a coating layer located on the surface of the cobalt-free base material, wherein the coating layer is a TeO2 coating layer, the mass of the TeO2 coating layer accounts for 0.1-0.8% of the mass of the base material, According to the invention, the TeO2 material is adopted to coat the cobalt-free high-nickel material, so that lithium ions can be embedded and emigrated in the material in the charging and discharging process, and the capacity and the first efficiency of the material are improved; and the coating layer reduces the contact area between the material and an electrolytic solution, and slows down the side reaction between the material and the electrolyte, so that the cycle performance of the material is improved, the oxygen loss of the material is slowed down, and the gas production is reduced so as to improve the high-temperature cycle performance and safety of the material.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and relates to a cobalt-free positive electrode material and a preparation method and application thereof. Background technique [0002] In recent years, the development of the power battery market has entered the fast lane, and people urgently need a cathode material with low cost, high energy density, high cycle performance and high safety. At present, the cathode material LiCoO on the market 2 And ternary materials (NCM) cannot meet the above conditions at the same time, the main reason is that the price of cobalt element continues to rise, and cobalt is also a non-environmentally friendly element. Ni in the process of charge and discharge in the ternary material 2+ and Li + It is worth noting that NM and NCM cathodes with the same Ni content have comparable discharge capacities at 0.1C. At the same time, NM cathodes show better cycle stability and thermal stability than NCM. ...

AI Technical Summary

Problems solved by technology

The cycle performance of the materials mentioned is poor, the gas production of the battery increases, and the safety performance decreases

[0004] CN112786834A discloses a positive pole piece and a lithium ion battery containing it, the positive pole piece includes a positive material layer, and the positive active material in the positive material layer includes cobalt-free binary materials and ternary single crystal materials, so The chemical formula of the cobalt-free binary material is LiNi x mn 1-x o 2 , the chemical formula of the ternary single crystal material is LiNi a co b mn 1-a-b o 2 , the particle size of the ternary single crystal material is smaller than that of the cobalt-free binary material, and the cobalt-free material is doped with the ternary single crystal material, and the cost is relatively high

[0005] The above scheme has the problem of excessive gas production or high cost during the cycle. Therefore, it is necessary to develop a low-cost cobalt-free cathode material while improving the gas production problem of cobalt-free cathode materials.

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