Effects of heating rate on morphology and performance of lithium iron phosphate synthesized by hydrothermal route in organic-free solution

Abstract

Flake-like LiFePO4 were hydrothermally synthesized in an organic-free solution at heating rates of 0.5, 1.5, 3, and 5 °C min−1. The heating rate has a marked influence on crystal morphology but scarcely on phase purity. The reason for morphology variations is discussed based upon the solubility of precursors Li3PO4 and Fe3(PO4)2·8H2O. The optimum heating rate for hydrothermal synthesis of LiFePO4 is 3 °C min−1. The as-synthesized material exhibits a high specific capacity, excellent rate capability, good low-temperature performance and Li+ diffusivity after carbon coating, all of which could be ascribed to shortened Li+ diffusion distance and higher crystallization degree of the crystalline.