Synthesis and characterization of Sn-doped LiMn2O4 cathode materials for rechargeable Li-ion batteries

Spinel LiSnxMn2-xO4 (x=0, 0.02, 0.04) was synthesized based on the controlled crystallization. The process started with the preparation of pristine or Sn-doped MnCO3, followed by heat-treatment to produce the precursor Mn2O3. Then, LiMn2O4 was obtained by sintering of the mixture of Mn2O3 and Li2CO3. The structural and electrochemical properties of as-prepared cathodes were investigated by X-ray diffraction, scanning electron microscopy, inductively coupled plasma-atomic emission spectrum, cyclic voltammetry, and charge-discharge cycling. The coin cells with LiSnxMn2-xO4 as the cathode were tested at a current density of 0.5 mA cm(-2) in the voltage range of 3.35-4.35 V at room temperature and in the voltage range of 3.35-4.20 V at 55 degrees C, respectively. The results show that the lattice constants of Sn-doped samples are reduced, but their cyclabilities are improved. (C) 2008 The Electrochemical Society.