▎ 摘　　要

NOVELTY - Lithium iron phosphate composite material comprises lithium iron phosphate composite material and three-dimentional graphene, where three-dimentional graphene content in composite material is 6-10 wt.%, and carbon content is 7-7.5 wt.%. USE - Lithium iron phosphate composite material used as battery cathode material. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing lithium iron phosphate composite material, which involves: (A) preparing graphite oxide solution by adding 1-10 gram graphite powder to 50-100 milliliter concentrated sulfuric acid; (B) adding 1- 10 gram in ice water bath sodium nitrate, 5-20 gram potassium permanganate, continuously reacting for 1-3 hours at 30-50 degrees C, after stirring for 1-3 hours; (C) adding 100-200 milliliter distilled water; (D) reacting for 5-20 minutes after continuously reacting for 10-30 minutes at 90-100 degrees C and finally adding 10-30 milliliter of 30 wt.% hydrogen peroxide till no bubble is generated and solution is golden; (E) filtering when it is hot, washing until pH of washing liquid is 6.9-7 to obtain graphite oxide, using obtained graphite oxide to prepare 1-10 milligram per milliliter of graphite oxide aqueous solution; (F) preparing lithium iron phosphate composite material by adding 0.5-3 gram phosphate 10-100 milliliter in graphite oxide aqueous solution; (G) adding iron source according to mol ratio of lithium phosphate and iron of 1:(1-1.05) to from lithium phosphate and iron source of 5-20 wt.% of total mass of carbon source; (H) stirring for 1-3 hours after ultrasonic treatment for 1-3 hours in water bath at 20-30 degrees C; (I) putting into the reaction kettle, and reacting for 100-200 degrees C at 10-24 hour; (J) filtering and washing the product below 0 degrees C in environment storage for 12-48 hours in freezing dryer 24-72 hours; (K) burning for 1-10 hours at 400-600 degrees C in inert atmosphere; (L) adding phosphate in product after burning and mixing and grinding iron source of 5-20 wt.% of total mass; and (M) calcining for 10-24 hours at 600-750 degrees C in an inert atmosphere after grinding uniformly to obtain desired product.