NOVELTY - Preparation of lithium-iron phosphate composite material involves adding phosphoric acid, lithium oxalate and ferric chloride sources, doping with cobalt nitrate and vanadium nitrate, uniformly mixing obtained mixture in polyvinyl alcohol solvent and deionized water, controlling pH to form sol-gel precursor, adding sucrose and citric acid with deionized water to obtain carbon source mixture, adding carbon source mixture into sol-gel precursor, reacting, evaporating water, sintering, grinding, decomposing, sintering, naturally cooling and grinding into particles.    USE - Preparation of lithium-iron phosphate composite material (claimed) used for lithium-ion battery.    ADVANTAGE - The lithium-iron phosphate composite material has high specific capacity and favorable charge and discharge characteristics and durability.    DETAILED DESCRIPTION - Preparation of lithium-iron phosphate composite material involves preparing lithium-iron phosphate precursor by adding phosphoric acid, lithium oxalate and ferric chloride sources with molar ratio of phosphorus, lithium and iron of (1-1.5):(1-1.2):(1-1.3), doping with cobalt nitrate and vanadium nitrate, uniformly mixing obtained mixture doped with cobalt nitrate and vanadium nitrate in polyvinyl alcohol solvent and deionized water, controlling pH of obtained solution (S1) to 5-8 to form sol-gel precursor, preparing carbon source mixture by adding sucrose as carbon source and citric acid as complexing agent with deionized water to obtain carbon source mixture, preparing dry gel by adding carbon source mixture into sol-gel precursor, reacting at 70-90 degrees C for 1-3 hours and evaporating water to obtain dry gel, sintering, grinding dry gel using ball mill under an inert gas atmosphere protection environment at 100-20 degrees C for 2-4 hours, raising temperature to 400-500 degrees C, decomposing for 3-5 hours using argon gas atmosphere protection environment, sintering at 800-1000 degrees C for 6-8 hours, naturally cooling and grinding into particles having particle diameter of less than 200 nm, to obtain lithium-iron phosphate composite material. The molar ratio of lithium in lithium oxalate, vanadium in vanadium nitrate and cobalt in cobalt nitrate is (0.03-0.05):(0.02-0.03):1. The mass ratio of sucrose, citric acid and deionized water is 2-3:1-2:6-8. The molar ratio of carbon source mixture and sol-gel precursor is 1:1.