Lithium cobalt oxide positive electrode material with stable surface structure and preparation method of lithium cobalt oxide positive electrode material

Abstract

The invention relates to a lithium cobalt oxide positive electrode material with a stable surface structure and a preparation method thereof. The lithium cobalt oxide positive electrode material comprises an inner core and a surface layer, the inner core is LiCo1-aAlaO2, and a is greater than or equal to 0 and less than or equal to 0.01; and the surface layer is a lithium-containing spinel structure Li < x > Co < 1-x-y-z > Ti < y > Mg < z > Co < 2-n > Al < n > O < 4 > with a nanometer size. According to the method, lithium carbonate and cobaltosic oxide with a core-shell structure are subjected to high-temperature sintering, a sintering furnace is vacuumized in the high-temperature heat preservation process after lithium cobalt oxide is formed in a high-temperature section, and cooling is started after heat preservation is conducted for a period of time; and setting a low-temperature heat preservation section in the cooling process, and introducing a certain flow of gas to obtain a continuous and uniform lithium-containing spinel structure with a nano size, thereby forming the lithium cobalt oxide positive electrode material. The lithium cobalt oxide with the stable surface structure has good ionic conductance and electronic conductance, has the stable HF acid-resistant surface structure, exerts high energy density and has good cycle life.

Description

technical field [0001] The invention relates to a lithium cobalt oxide with high discharge specific capacity, in particular to a lithium cobalt oxide with a stable surface structure, namely Li x Co 1-x-y-z Ti y Mg z Co 2-n Al n O 4 The lithium cobalt oxide positive electrode material and the preparation method thereof belong to the field of lithium ion battery electrode materials. Background technique [0002] Improving the working voltage to obtain lithium-ion batteries with high energy density is a key technology in the battery industry. [0003] The main factor affecting the capacity decay of high-voltage lithium cobalt oxide in long cycles is the stability of the particle surface structure. During long cycles, HF in the electrolyte continuously reacts with the surface layer of lithium cobalt oxide, forming LiF, Li-containing lithium cobalt oxide layers on the surface layer of lithium cobalt oxide. 2 CO 3 The CEI film consumes Li and even dissolves Co, which reduc...

AI Technical Summary

Problems solved by technology

[0004] Cobalt Tetroxide CoO·Co 2 o 3 It has the ability to store lithium ions, but CoO·Co 2 o 3 The tight structure and small interstitial sites of the spinel structure are not conducive to the extraction and intercalation of lithium ions

[0005] The positive electrode material lithium cobalt oxide generally uses lithium carbonate, tricobalt tetroxide CoO·Co 2 o 3 It is produced by high-temperature solid phase sintering of raw materials in a certain air atmosphere, and there is the problem of unstable surface structure as mentioned above

Images