Rapid and facile synthesis of Mn doped porous LiFePO4/C from iron carbonyl complex

Porous Mn-doped LiFePO4/C cathode material was synthesized by facile and fast microwave assisted solid state reaction from iron carbonyl complex using citric acid as reducing agent and source of carbon. The microstructure and electrochemical performance were systematically investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), field emission scanning electron microscope (FE–SEM), transmission electron microscope (TEM), Raman spectroscopy, charge–discharge cycling, cyclic voltammogram and electrochemical impedance spectroscopy. It was found that the as-prepared composites have a single phase of orthorhombic olivine-type structure and Mn2+ has successfully introduced into the M2(Fe) sites. The electrochemical properties of LiFe0.99Mn0.01PO4/C were compared with bare LiFePO4 and LiFePO4/C composite prepared by identical route. Compare to as-prepared LiFePO4/C composites, LiFe0.99Mn0.01PO4/C demonstrates a remarkable electrochemical property in terms of discharge capacity, electrochemical reversibility and cycling performance with an initial discharge capacity of 163.2 mAh g−1 at a discharge rate of 0.1 C. It also performed excellent even at higher current densities. The improved electrochemical performance was attributed to the smaller particle size, porosity, the enhancement of the P–O bond and the facilitation of Li+ ion “effective” diffusion, induced by Mn2+-substitution.