Solid chemical reaction by microwave heating for the synthesis of LiFePO4 cathode material

Abstract

LiFePO4 has been synthesized using FeC2O 4-2H2O, LiOH-H2O and NH4H 2PO4 as raw materials by a temperature controllable microwave heating oven. The products were characterized by X-ray diffraction, scanning electron microscope and electrochemical methods. Measurement of dielectric properties of individual raw materials and products at a constant microwave frequency revealed that the starting mixture preheated at 320°C as well as added acetylene black were well microwave absorbers. Single phase olivin-type LiFePO4 with uniform and fine particle sizes was successfully synthesized by microwave heating at 350°C in 15 min. The LiFePO4 cathode materials thus obtained had a higher discharge capacity and better cycle performance than those of the LiFePO4 sample by a conventional solid-state reaction.