LONG-LIFE LITHIUM MANGANATE-BASED POSITIVE ELECTRODE MATERIAL WITH SPECIFIC COMPOSITION AND MORPHOLOGY CHARACTERISTICS AND PREPARATION METHOD THEREFOR

摘要

Disclosed are a long-life lithium manganate-based positive electrode material with specific composition and morphology characteristics and a preparation method therefor. The method involves preparing a fluorine-containing lithium-rich lithium manganate-based positive electrode material co-doped with ions of both cobalt and aluminium metals, wherein same is regular in morphology and excellent in performance, particularly in high temperature cycle performance, from lithium hydroxide, lithium fluoride, manganese acetate, and metal salts of doping ions as raw materials, with citric acid as a chelating agent, by controlling the contents of cobalt and aluminium and the calcination temperature during preparation by means of a sol-gel method. The lithium manganate-based positive electrode material has the characteristics of an octahedral structure morphology with the apexes cut off, an excellent rate performance, and a long high-temperature life. After subjecting the material to a charge/discharge at 2C and 5C rates (55°C), the specific initial discharge capacities thereof respectively reach 116.9 mAh/g and 112.6 mAh/g; and after subjecting same to 800 cycles at charge/discharge rates of 2C and 5C at 55°C, the capacity retention ratios thereof both reach 72% or more.