Effect of Annealing on Crystal Orientation and Electrochemical Performance of Nanocrystalline LiFePO₄

摘要

Nano single-crystalline LiFePO4 (LFP) with large (010) plane exposure was synthesized by the hydrothermal method, followed by annealing to alleviate the main limitations of LiFePO4 cathode material. The XRD results indicated that after annealing, the sample gained the preferred crystal orientation with a (020) crystallographic direction. Annealed LiFePO4 showed a significantly improved capacity and excellent cycling and rate stability. Further electrochemical impedance analysis indicated that annealed LiFePO4 has smaller film resistance Rsf, smaller charge-transfer resistance Rct, and a larger diffusion coefficient of lithium ion (DLi).