Synthesis, Characterization and Electrochemical Performance of Li₂Mn_0.7Fe_0.3SiO₄ Prepared from Solid-state Reaction

Li2MSiO4(M=Mn, Co, Ni) is a potential high capacity cathode material because of its outstanding properties that exchange of two electrons per transition metal atom is possible and the theoretical capacity of Li2MSiO4 can reach as high as 330 mAhg(-1). In this family, the cathode performance of Li2MnSiO4 synthesized by solution route has been published recently. However, it seems that the cycle life of Li2MnSiO4 fell short of our expectation. In this work, the Li2Mn0.7Fe0.3SiO4 cathode material was synthesized by traditional solid-state reaction method. The prepared powder was consisted of majority of Li2Mn0.7Fe0.3SiO4 and minor impurities which were examined by XRD. FESEM morphology showed that the products of Li2Mn0.7Fe0.3SiO4 and Li2MnSiO4 have similar particle size (about 50-300 rim). The electrochemical performance of Li2Mn0.7Fe0.3SiO4, especially for reversible capacity and cycle life, exhibited better than those of Li2MnSiO4.