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

Preparing LiFePO 4 cathode from FeSO 4 ·7H 2 O waste residue, the by-product of TiO 2 production, can effectively reduce the LiFePO 4 cost and alleviate the environmental pollution problem. However, the inevitable Ti impurity may affect the structure and electrochemical performance of LiFePO 4. Based on the actual Ti content in FeSO 4 ·7 H 2 O waste residue, herein, we prepared the Ti-doped LiFePO 4 , which is expected to get the suitable Ti content. Importantly, Ti-doped with an appropriate amount can reduce the particle size of LiFePO 4 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 LiFePO 4 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 LiFePO 4 and solving the problem of environmental pollution. [Display omitted] • The effect of impurity Ti on LiFePO 4 is illustrated. • The sample with optimal impurity Ti content (LFP-2) endows the highest rate and cycle performance. • The result can be attributed to the diminution of particle size and the improvement of conductivity. [ABSTRACT FROM AUTHOR]