Improving electrochemical properties of lithium iron phosphate by addition of vanadium

The poor conductivity, resulting from the low lithium-ion diffusion rate and low electronic conductivity in the LiFePO4 phase, has posed a bottleneck for commercial applications. Well-crystallized LiFePO4-based powders with vanadium addition were synthesized with solution method. The synthesized powders are coated with carbon. The powder containing the well-mixed LiFePO4 and Li3V2(PO4)3 phases (LFVP) with narrow distributed particle size ranging between 0.5 and 2.5 μm exhibits improved electrochemical performance. The small particle size and the presence of the electronically conductive mixed phases can be the reasons why the cells containing LFVP exhibit the high discharge capacity of about 100 mAh g−1 at 10 C, whereas the samples with single phase, such as LiFePO4 and Li3V2(PO4)3, have the discharge capacity less than 80 Ah g−1 at the same rate.