Morphology-controllable solvothermal synthesis of nanoscale LiFePO4 in a binary solvent

LiFePO4 (LFP) nanobars, microplates and nanorods have been selectively synthesized via a solvothermal method in a water-ethylene glycol (EG) binary solvent with H3PO4, LiOH·H2O, and FeSO4·7H2O as starting materials. The morphology and size of the as-obtained LFP products can be deliberately controlled by varying the volume ratio of EG to water. The formation mechanism and electrochemical properties of different LFP morphologies have been investigated. With carbon coating, the Li-ion diffusion coefficients of LFP nanorods, nanobars and micro-plates are 2.58×10−9, 2.91×10−10, and 7.22×10−10 cm2 s−1, respectively. For the carbon-coated nanorods, excellent rate capability and cyclability were attained. At 5 C, the capacity was 141 mAh g−1 for the first cycle and maintained 120 mAh g−1 after 100 cycles; at 10 C, the capacity was still as high as 132 mAh g−1.