Enhanced electrochemical properties of LiMn1-xFexPO4/C composite cathode materials prepared by sol–gel method

• LiMn1-xFexPO4/C nanocomposites (x=0, 0.1, 0.3, and 0.5) were synthesized by sol–gel method.
• Initial specific discharge capacities of 96.8–161.5 mA h g−1 at 0.05 C were obtained.
• LiMn0.5Fe0.5PO4/C exhibited an excellent reversible capacity of 132 mA h g−1 at 1 C.
• Fe2+ doping improves Li insertion and extraction, as well as electrical conductivity.

Olivine-type LiMn1-xFexPO4/C(x=0, 0.1, 0.3 and 0.5) composite materials were synthesized by the sol–gel method employing N,N-dimethylformamide (DMF) as a dispersing agent, and the structure and morphology of the as-prepared nanoparticles were characterized. For Fe2+ doping contents of x=0, 0.1, 0.3, and 0.5, initial specific discharge capacities of 96.8, 137.6, 152.3, and 161.5 mA h g−1 at 0.05 C were obtained, respectively. The LiMn0.5Fe0.5PO4/C composite in particular exhibited an excellent reversible capacity of 132 mA h g−1 at a charge–discharge rate of 1 C. Finally, LiMn0.5Fe0.5PO4/C retained 155.5 mA h g−1 (96.3%) of the initial specific discharge capacity after 50 cycles, demonstrating excellent cyclability.