Lithium cobalt oxide material of core-shell structure and preparation method of lithium cobalt oxide material

Abstract

The invention discloses a lithium cobalt oxide material of a core-shell structure and a preparation method of the lithium cobalt oxide material. According to the lithium cobalt oxide material, both the core and the shell of the material are made of lithium cobalt oxides as substrates, the core is optionally doped with a doping element A, the shell is doped with a doping element X, and the weight percentage of the doping element X in the shell is greater than that of the doping element A in the core. The preparation method comprises the following steps: 1, mixing a lithium source, a cobalt source and a doping substance A', and performing calcining, crushing and screening in sequence, so as to obtain a core substrate material; 2, mixing the lithium source, the cobalt source and a doping substance X' so as to obtain a shell precursor; 3, mixing the shell precursor with the core base material, and performing thermal treatment, thereby obtaining the lithium cobalt oxide material of the core-shell structure. The lithium cobalt oxide material of the core-shell structure is novel in structure, the core and the shell are made of same substrate materials with slight doping amount differences, the core and the shell can be very well transitioned and fused together, and situations such as cracking or powdering can be avoided in the charge and discharge process; the lithium cobalt oxide material is simple in preparation and easy in industrial production.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a lithium cobaltate material, in particular to a lithium cobaltate material with a core-shell structure and a preparation method thereof. Background technique [0002] Lithium cobalt oxide (LiCoO 2 ) materials have the advantages of high voltage and high specific capacity, and are the most commonly used materials in 3C electronic products. Lithium cobalt oxide currently used in the market has an urgent vision for improving volumetric energy density. There are two ways to increase the volume energy density: one is to increase the compaction density of lithium cobalt oxide, and the other is to increase the operating voltage of lithium cobalt oxide. The space available for increasing the compaction density in the current battery manufacturing system is quite limited, so the only way to increase the volumetric energy density of lithium cobalt oxide is to increase the...

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Problems solved by technology

[0003] In the prior art, in order to improve the structural stability of the lithium cobalt oxide material, some elements are doped in the lithium cobalt oxide material, but these doped substances are not electrochemically active, which will cause the material to be grammatically capacity reduction

Another way is to set a coating layer on the surface of lithium cobalt oxide, which cannot be completely compatible with the internal lithium cobalt oxide material. In this way, the coating layer will cause disadvantages such as poor rate performance and large internal resistance of the battery. This is contrary to our original intention of increasing the volumetric energy density of lithium cobalt oxide materials

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