Enhanced cycle and rate performances of Li(Li0.05Al0.05Mn1.90)O4 cathode material prepared via a solution combustion method for lithium-ion batteries
Abstract A (Li, Al)-co-doped spinel Li(Li 0.05 Al 0.05 Mn 1.90 )O 4 (LAMO) cathode material has been rapidly prepared by a solution combustion method. The structure of as-prepared samples was characterized by X-ray diffraction (XRD), which shows that (Li, Al)-co-doping does not change the intrinsic spinel structure of LiMn 2 O 4 . The morphology and particle size of the as-prepared samples were analyzed by field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM), which indicate that the LAMO has high crystallinity, regular truncated octahedran morphology and uniform particle size distribution. The X-ray photoelectron spectrometer (XPS) measurement shows that (Li, Al)-co-doping increases the average valence of Mn. The cycle performance was evaluated by galvanostatic charge-discharge cycling test. The results show that LAMO maintains a high discharge specific capacity of 98.0 mAh g − 1 with a capacity retention of 82.4% after 1000 cycles at 5C (1C = 148 mAh g − 1 ) compared with that of 60.7 mAh g − 1 with a capacity retention of 60.4% for the pristine LiMn 2 O 4 (LMO). Furthermore, LAMO exhibits obvious improvement of elevated-temperature cyclic performance, resulting in a superior capacity retention of 73.9% after 400 cycles at 1C at 55 °C with an initial discharge specific capacity of 107.2 mAh g − 1 , which is much higher than that of 14.6% for the pristine LMO. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies certify that (Li, Al)-co-doping improves the reversibility and enhances kinetics process of electrode.