Elevated temperature cyclic performance of LiAlxMn2−xO4 microspheres synthesized via co-precipitation route

Abstract

The spinel LiAlxMn2−xO4 (x=0, 0.02, 0.06 and 0.1) microspheres were synthesized via co-precipitation route. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge–discharge tests. It has been found that the LiAlxMn2−xO4 (x=0, 0.02 and 0.06) samples have well spherical morphology, especially the LiAl0.06Mn1.94O4 sample exhibits the best reversibility and highest cyclic stability at elevated temperature. Meanwhile, the EIS results demonstrate that the diffusion of Li+ in LiAl0.06Mn1.94O4 is effectively improved. More importantly, the LiAl0.06Mn1.94O4 sample exhibited obviously improved electrochemical performance comparing with the pure LiMn2O4, which delivers an initial discharge capacity of 117.4mAhg−1 at a rate of 1C with capacity retention of 97.0% after 100cycles at 55°C. These remarkable improvements indicate that Al-doped LiMn2O4 via co-precipitation route is an effective way to improve the elevated temperature performance of LiMn2O4.