Dehydration of FePO₄·2H₂O for the Synthesis of LiFePO₄/C: Effect of Dehydration Temperature

摘要

To study the effect of dehydration temperature on synthesis and electrochemical performance of o LiFePO4/C, FePO4·2H2O is dehydrated at different temperatures (200-700 C) and the resulting FePO4 is adopted as a raw material to synthesize LiFePO4/C composite. The results show that FePO4·2H2O can be fully dehydrated at a temperature above 184 oC, the crystalline form, particle size and morphology of the dehydrated FePO4 varies with dehydration temperature, and the synthesized LiFePO4/C composites from these FePO4 have similar crystallinity, particle size and morphology, but have different electrochemical performance. Among all samples, the LiFePO4/C synthesized from the o FePO4 dehydrated at 500 C exhibits the best electrochemical performance. From these results, it is suggested that α-quartz FePO4 with a trigonal structure (P3121) is an optimum form for efficient synthesis of high performance LiFePO4/C composite, and the dehydration of FePO4·2H2O should be controlled at a temperature around 500 oC.