Effect of Ti content on preparation of LiFePO4 cathode from FeSO4·7H2O waste residue

Abstract

Preparing LiFePO4 cathode from FeSO4·7H2O waste residue, the by-product of TiO2 production, can effectively reduce the LiFePO4 cost and alleviate the environmental pollution problem. However, the inevitable Ti impurity may affect the structure and electrochemical performance of LiFePO4. Based on the actual Ti content in FeSO4·7 H2O waste residue, herein, we prepared the Ti-doped LiFePO4, which is expected to get the suitable Ti content. Importantly, Ti-doped with an appropriate amount can reduce the particle size of LiFePO4 and shorten the migration distance of Li+ ions. Moreover, the impurity Ti as a dopant with an appropriate amount can modulate the band structures, improve the conductivity of LiFePO4 and enhance the diffusion kinetics of Li+ ions. Hence, the sample with optimal Ti content (LFP-2) shows distinguished electrochemical performance with excellent rate capacity (93.5 mAh g−1 at 10 C) and stable long-term cycle performance (capacity retention of 94.9% after 300 cycles at 1 C with an initial capacity of 151.3 mAh g−1). This research is conducive to reducing the production cost of LiFePO4 and solving the problem of environmental pollution.