High-voltage composite spinel-coated positive electrode material and preparation method thereof

Abstract

The invention provides a high-voltage composite spinel-coated positive electrode material and a preparation method thereof. The positive electrode material comprises a lithium cobalt oxide core, a spinel-type lithium nickel manganese oxide middle layer and a solid electrolyte surface layer. The invention provides a positive electrode material with a composite coating layer on the surface, and the coating layer has good lithium ion conductivity, so that the positive electrode material is high in discharge capacity and excellent in cycle life under a high voltage without influencing a discharge platform, the volume energy density of a lithium ion battery is improved, and the corrosion of HF to the surface layer of the material can be reduced; and the high-temperature cycle life of the material is prolonged, so that the defects of unstable use structure of the positive electrode material under high charging cut-off voltage or poor cycle performance and low discharge capacity even if the structure is stable in the prior art are overcome, the high-temperature cycle performance is improved, and the material is more suitable for the actual use working condition of the material.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a high-voltage composite spinel-coated positive electrode material and a preparation method thereof. Background technique [0002] In the 1870s, M.S.Whittingham (one of the 2019 Nobel Prize winners in Chemistry) worked for Exxon Corporation in the United States. He developed the prototype of lithium-ion batteries: TiS 2 It is a secondary battery based on lithium ion intercalation reaction with Li-Al alloy as the positive electrode and the negative electrode as the negative electrode. Due to the energy density of the system and safety issues, TiS 2 The commercialization of the battery was not successful, but the new working principle of the battery proposed by Whittingham - the intercalation reaction, undoubtedly became the cornerstone of the successful commercialization of SONY lithium-ion batteries. [0003] In 1980, Professor J.B. Goodenough of the Department ...

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Problems solved by technology

[0022] In view of this, the present invention aims to propose a high-voltage composite spinel-coated positive electrode material and its preparation method. The surface is provided with a composite coating layer. The coating layer has good lithium ion conductivity and does not affect the In the case of a discharge platform, the positive electrode material has a high discharge capacity and excellent cycle life at high voltage, improves the volumetric energy density of the lithium-ion battery, reduces the corrosion of the surface layer of the material by HF, and improves the high-temperature cycle life of the material, thereby overcoming The positive electrode materials in the prior art are structurally unstable when used at a high charge cut-off voltage, or even if the structure is stable, the cycle performance is not good and the discharge capacity is not high enough, and the high temperature cycle performance is improved, which is more suitable for the actual use of the material Condition

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