Preparation of LiMn_(0.4)Fe_(0.6)PO_4/C Composite by A New Route Combining Solid-state Reaction with Hydrothermal Synthesis

The olivine type LiMn0.4Fe0.6PO4 was synthesized via a new route that combining solid-state reaction with hydrothermal synthesis from Li2CO3,FeC2O4·2H2O,MnCO3 and NH4H2PO4(at molar ratio of 5:6:4:10).The structure,particle size and surface morphology of these cathode active materials were investigated by XRD,SEM and TEM techniques.The electrochemical properties of LiMn0.4Fe0.6PO4/C as cathode in lithium-ion cells were tested via cyclic voltammetry and galvanostatic charge-discharge measurements.Phase-pure particles of size ~120 nm are prepared with a conductive,thin web of carbon surrounding them.Cyclic voltammetry shows the active voltage range of the material which consists of two pairs of redox peaks:3.5 V corresponding to Fe3+/Fe2+ reaction and 4.0 V corresponding to Mn3+/Mn2+ reaction.An initial discharge capacity of 160 mAh/g at 0.1C,143 mAh/g and a stable cycling property at 0.5C are obtained for the LiMn0.4Fe0.6PO4/C composite.