A SYNTHESIS ROUTE FOR LITHIUM IRON PHOSPHATE PREPARED BY IMPROVED COPRECIPITATION

Pure lithium iron phosphate and Mo-doped lithium iron phosphate were synthesized via improved coprecipitation, followed by spray dry processing and sintering at a high temperature for crystallization. The synthesis was based on a key step to promote the dissolution of Fe powder by the addition of Cu or CuO powder in phosphoric acid solution. The improved coprecipitation process could achieve homogeneous mixing of the reactants at the molecular level. The crystalline particle size of the LiFePO4 was between 20 and 70 nm. All the samples were pure single-phase indexed with orthorhombic Pnmb space group. The electrochemical performance of LiFe0.96Mo0.04PO4, including its reversible capacity, cycle number and charge-discharge characteristics, were all better than those of pure LiFePO4.