The synthesis, structure, and performance of carbon-containing Li2MnxFe1-xSiO4 were studied in this work. A synthesis route has been developed for Li2MnxFe1-xSiO4 materials, i.e., the carbon-containing Li2MnxFe1-xSiO4 was synthesized by a solution route. The results of X-ray diffraction show that Li2MnxFe1-xSiO4 solid solutions can be achieved in a wide compositional range. A capacity of 214 mAh/g and energy density of 593 Wh/kg has been achieved for the Li2MnxFe1-xSiO4 (x=0.5) sample. (c) 2006 The Electrochemical Society.