Novel fabrication of Li4Ti5O12 coated LiMn2O4 nanorods as cathode materials with long-term cyclic stability at high ambient temperature

Abstract

Spinel LiMn2O4 has attracted increasing interest as promising cathode material owing to its low cost, high safety, and environmental friendliness. But the further development of LiMn2O4 is restricted by fast capacity fading upon cycling, especially at high temperatures. Herein, the one-dimensional (1D) Li4Ti5O12 coated LiMn2O4 nanorods (LMO-LTO) are successfully prepared by combining sol-gel and solid-state calcination method and ultimately enhance the cathode utilization in high-temperature and long-cycling conditions. The as-prepared LMO-LTO cathode delivers a high initial discharge capacity of 128.5 mAh g-1 at 0.1 C rate and exhibits a promising discharge capacity over 74.5 mAh g-1 at 10 C rate. Even under an elevated temperature of 55OC, it still maintains 74.8% of its initial capacity at 1 C rate. Furthermore, the electrochemical impedance spectra (EIS) measurement confirm that compared with the pure LiMn2O4 nanorod, lower the charge transfer resistance (Rct) and enhanced Li+ diffusion coefficient are also strong evidences of the improved electrochemical performance of LiMn2O4 nanorods after Li4Ti5O12 coating.