High purity lithium iron phosphate/carbon composites prepared by using secondary lithium source

Various lithium salts including lithium carbonate, lithium hydroxide, lithium acetate and lithium citrate were used as secondary lithium sources for the synthesis of lithium iron phosphate/carbon composites with cheap iron sources in the form of Fe and FePO4. Samples were characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and constant-current charge–discharge tests. The results showed that lithium carbonate derived product generated a high purity LiFePO4 phase with high tap densities. Furthermore, satisfactory electrochemical performance with an initial discharge capacity of 146.1 mAh g− 1 at 0.5 C rate and good capacity retention of 95.2% after 50 cycles were achieved.