Fast and Low Cost Synthesis of LiFePO4 Using Fe3+ Precursor

Submicrometer and phase-pure LiFePO4 was prepared by carbothermal reduction of Fe2O3 using a preliminary mechanical activation. The reaction mechanism, particle size, and electrochemical performance of as-prepared LiFePO4 were studied and compared with LiFePO4 obtained from the Fe2+ precursor (FeC2O4 center dot 2H(2)O) using thermal analysis, X-ray diffraction, Mossbauer spectroscopy, scanning electron microscopy, and galvanostatic cycling. The carbothermal synthesis of LiFePO4 from Fe2O3 in inert atmosphere is a multistep process, including first the formation of Li-Fe3+ phosphates, mainly pyrophosphate LiFeP2O7. A single-phase high crystalline LiFePO4 is formed at temperatures >= 700 degrees C. The preliminary mechanical activation accelerates the reaction due to a very fine grinding and an intimate mixing of the reactants. The specific discharge capacity of LiFePO4 prepared from iron oxide is comparable with that of LiFePO4 prepared from iron oxalate (similar to 155 mAh/g). (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3489292] All rights reserved.