Drastic enhancement in the rate and cyclic behavior of LiMn2O4 electrodes at elevated temperatures by phosphorus doping

Abstract

Herein we provide an effective strategy for drastically improving the cyclic behavior and rate capability of an LiMn2O4 (LMO) electrode at elevated temperature through P element doping. The P-doped LiMn2O4 materials are characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectrometry analysis. The results show that the P element is effectively and uniformly doped within the LiMn2O4 crystal lattice and is beneficial for growth of the truncated octahedral crystal structure. The electrochemical results reveal that P doping can greatly improve the cycling performance of LiMn2O4 electrodes, especially improving the rate capability at elevated temperatures. At a high 10C rate of current density and 55 °C, the optimized LMO (1.5 wt% P) electrode shows the highest initial specific capacity of 101.2 mAh g−1, which become 74.4 mAh g−1 after 500 cycles, corresponding to 73.5% capacity retention. Under similar conditions, the LMO (2.5 wt% P) electrode shows an initial discharge capacity of 78.5 mA g−1, which become 72.2 mAh g−1 after 500 cycles, corresponding to 92.3% capacity retention.