Enhanced high-rate cycling performance of LiMn₂O₄ cathode materials by coating nano-TiO₂

Abstract

LiMn2O4 has the advantages of low cost and no pollution, and is widely regarded as a large-scale lithium battery cathode material. However, the capacity decays rapidly, which seriously affects the application of LiMn2O4 cathode materials. Therefore, improving the cycling performance of LiMn2O4 is the focus of current research. LiMn2O4 precursors were prepared by chemical precipitation and the precursors were coated to prepare LiMn2O4/TiO2 composites. X-ray diffraction and scanning electron microscopy showed that LiMn2O4 had been successfully combined with TiO2. Electrode charge–discharge and electrochemical impedance tests showed that LiMn2O4/TiO2 had the best cycle performance at high rates. The initial discharge capacities of LiMn2O4/TiO2 reached 106.4 mAh·g−1 at 0.2 C. After 100 cycles, the 2 C capacity retention rates was 76.3 %, compared to only 66.5 % for pristine LiMn2O4. The improved electrochemical performance was attributed to the nanoscale oxides hindering the reaction between the electrolyte and the electrode, which effectively improved the stability of the material during high current charge and discharge.