LiFePO4/C composite particles were prepared by a gas-solid phase reaction. The precursor particles for the olivine compounds were prepared by an intimate mixing of Li2CO3, FeC2O4 center dot 2H(2)O, and (NH4)(2)HPO4 and by calcination at 350 degrees C in a N-2 atmosphere. Then, they were heated up to a predetermined temperature under a constant flow of hydrocarbon gas, which is a source of elemental carbon. The adjustment of the temperature enabled us to obtain the composite particles with few magnetic impurities (the spontaneous magnetization was less than 0.01 emu/g) as well as good electrical conductivity (the compact conductivity was higher than 10(-1) S/cm). The composite particles, synthesized under the optimized condition, showed a reversible capacity greater than 150 mAh/g at a low current density of 0.1 C. Simultaneously, they also exhibited a superior performance in both cycle stability and rate capability.