METHOD FOR PRODUCING COMPOSITE LITHIUM IRON PHOSPHATE MATERIAL AND COMPOSITE LITHIUM IRON PHOSPHATE MATERIAL PRODUCED THEREBY

摘要

A method for producing a composite lithium iron phosphate material, which comprises formulating lithium iron phosphate material and purified water at a weight ratio of 1:5-15 into a suspension solution, slowly adjusting the pH value of the suspension solution to 1-3 with phosphoric acid at a concentration of 5-30%, adding an analytically pure soluble chloride in an amount of 0.05 - 2% based on the molar amount of the lithium iron phosphate material; then adding ammonia water into the solution to adjust the pH value of the solution to 5-6 to obtain hydroxide colloid; drying liquid through spraying to prepare powder, and calcining at 300-450°C for 3-6 hours under an inert atmosphere; coating the oxide with high conductivity obtained by thermally decomposing the hydroxide colloid on the surface of the lithium iron phosphate material grains; ball milling and sieving the calcined material into a finished product. Also disclosed is the composite lithium iron phosphate material produced by such a method.