Improved Electrochemical Performances of Fe-Doped Limnpo4/C Through an Investigation of Different Iron Sources

Choice of iron sources is crucial to the improved electrochemical performances of LiMnPO 4 with poor electronic and ionic conductivity. Here, LiMn 0.8 Fe 0.2 PO 4 /C composites were synthesized through a rheological phase-assisted solid-state method using MnO and LiH 2 PO 4 as raw materials. Effect of different iron sources on the structure, morphology and electrochemical performances of as-prepared LiMn 0.8 Fe 0.2 PO 4 /C composite was investigated. The results suggest that LiMn 0.8 Fe 0.2 PO 4 /C composite prepared using soluble FeNO 3 as iron source possesses excellent rate performances of 136 and 129 mA·h·g −1 at 0.1 and 5 C, respectively and capacity retention of 95.1% for 400 cycles at 2 C. The excellent electrochemical performances may be attributed to the substitution of soluble iron source in favor of formation of (LiMnFePO 4 ) 0.8 @(LiFePO 4 ) 0.2 /C with core-shell structure. Core-shell structure can not only improve the electron conductivity of LiMnPO 4 material, but also prevent the capacity reduction caused by Mn 2+ dissolved in electrolyte