Patent ID: 8815338
Filing Date: 2014-08-26
Classification: C01B,H01M,Y02E

Abstract:
1. A method for producing a composite lithium iron phosphate material comprising following steps: a, mix lithium iron phosphate and purified water at a weight ratio of 1: 5-15 into a suspension solution; b, slowly adjust a pH value of the suspension solution to 1-3 with phosphoric acid at a concentration of 5-30% in weight, thereafter adding analytically pure soluble chloride in an amount of 0.05-2% of the molar amount of the lithium iron phosphate to the suspension solution; thereafter adding ammonia water at concentration of 4-6% in weight into the suspension solution to adjust the pH value of the suspension solution to 5-6 to obtain hydroxide colloid in the suspension solution; c, make the suspension solution having hydroxide colloid to become powder through hot spraying method; d, calcine the powder at 300-450° C. for 3-6 hours in inert atmosphere, the hydroxide colloid is decomposed thermally to obtain oxide with high conductivity which is coated on surfaces of the lithium iron phosphate having grains shape; and e, ball mill and sieve the lithium iron phosphate grains coated with oxide into a finished composite lithium iron phosphate material.