Inexpensive synthesis of metal-doped LiFePO4 from laterite lixivium and its electrochemical characterization

Nickel laterite lixiviums with different element concentrations are purified by fast phosphate co-precipitation method. ICP analysis confirms that the recovery of Ni, Co, Mn is around 90% based on lixiviums, and all iron is removed as FePO4·xH2O precursors. LiFePO4 samples with different dopant amounts are directly synthesized from the attained precursors, which require no further purification. SEM maps show the distribution of particle is homogeneous. EIS results show the resistant decreases by doping. The Rietveld refinement results show that suitable metal-doping could intrinsically expand Li diffusion channel and might prevent collapse of the crystal during cycling. Electrochemical studies confirm that the LiFePO4 samples prepared from laterite lixiviums, exhibit improved rate ability and better cycle-life property compared to pristine LiFePO4 (as we reported before), and the sample with 2.16% dopant owns the best performance, which retains almost 100% cycle efficiency after 310 cycles (up to 5 C).