Preparation method of fluoride modified lithium cobalt oxide positive electrode material

The invention relates to a preparation method of a fluoride modified lithium cobalt oxide positive electrode material, which comprises the following steps: (1) mixing hydroxyl cobalt oxide and lithium in a certain ratio by a tank mill, roasting at 1000 DEG C, and post-processing the roasted material to obtain small-particle single-crystal lithium cobalt oxide; (2) completely dissolving AlCl3. 6H2O, LiCl and NH4F in deionized water, slowly adding 15g of lithium cobalt oxide into the solution, heating and stirring, pouring the mixed solution into a PTFE (polytetrafluoroethylene) high-pressure hydrothermal reaction kettle, and drying in an air dry oven to obtain a base material; and (3) sintering the base material, and treating the sintered material to obtain the fluoride modified lithium cobalt oxide positive electrode material. The preparation method disclosed by the invention has the advantages that firstly, lithium fluoride and aluminum fluoride have a double-coating effect; and secondly, the lithium cobalt