Syntheses and electrochemical characterization of Li-rich Li₂Mn_1-x;Ti_xo₃ layered materials used for lithium ion batteries

Ti-doped Li₂MnO₃is synthesízed by a conventional solíd-state reaction. Scanning electron mícroscopy, X-ray diffraction and X-ray photoelectric spectroscopy analyses indicate Ti is successfully doped into Li₂MnO₃ structure and the doping could suppress agglomeration of primary particlesis efficiently. Electrochemical impedance spectroscopy and galvanostatic charge/discharge results show that, in the voltage window of 2.0〜4.6 V (vs Li/Li⁺)， doped sample Li₂M_{n0 97}Ti_{0 03}O₃ delivers an initial discharge capacity of 209 mAh • g^-1 with 99.5% coulombic efficiency; after 40 cycles the capacity retention is 94%. Even the current density increases to 400 mA'g^-1, the doped sample could still deliver 120 mAh·g^-1 capacity, which is more than twice of that of undoped Li₂MnO₃ (52 mAh·g^-1). Ti-doped Li₂MnO₃ show greatly improved cycling stability and rate performance, which is beneficial for promoting the commercial application of Li₂MnO₃ material.