Li2Fe1-xMnxSiO4/C cathode materials were synthesized by mechanical activation-solid-state reaction The effects of Mn-doping content roasting temperature soaking time and Li/Si molar ratio on the physical properties and electrochemical performance of the Li2Fe1-xMnxSiO4/C composites were investigated The materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) charge-discharge tests and AC Impedance measurements SEM images suggest that the morphology of the Li2Fe1-xMnxSiO4/C composite is sensitive to the reaction temperature Samples synthesized at different temperatures have different extent of agglomeration Being charged-discharged at C/32 between 1 5 and 4 8 V the Li2Fe0 9Mn0 1SiO4/C synthesized at the optimum conditions shows good electrochemical performances with an initial discharge capacity of 158 1 mAh g(-1) and a capacity retention ratio of 94 3% after 30 cycles AC impendence investigation shows Li2Fe0 9Mn0 1SiO4/C have much lower resistance of electrode/electrolyte interface than Li2FeSiO4/C (C) 2010 Elsevier Ltd All rights reserved