Low-cost LiFePO ₄ using Fe metal precursor

A nano-LiFePO ₄ possessing a plate-shaped morphology was synthesized by the solvothermal process using low-cost Fe metal powder as the starting precursor at a moderate temperature of around 230 °C under high pressure. Field-emission scanning electron microscopy (FE-SEM) images revealed the average thickness, length and width of the nanoplates to be 20, 100 and 100 nm respectively. The nanoplate-LiFePO ₄ delivered specific discharge capacities of 171 mA h g ^-1 with impressive cycle performance until 150 cycles and high rate capabilities as capacities of 125 mA h g ^-1 was achieved at elevated C-rates of 16 C. Field-emission transmission electron microscopy (FE-TEM) confirmed the growth of the nanoplates along the [010] and [101] crystallographic directions. Solid state ⁷Li magic angle spinning nuclear magnetic resonance study suggests progressive Li-ion intercalation/de-intercalation along a specific crystallographic direction and appears to support the domino-cascade model. Extended X-ray absorption fine structure spectroscopy (EXAFS) studies indicated a flexible LiFePO ₄ nanostructure due to the reconstruction of crystals' surface and thereby realize enhanced capacities. We believe that the strategy to adopt Fe-metal precursor in order to obtain such high performing nano-LiFePO ₄ is very promising for large-scale commercialization from a cost perspective.