Cerium doped LiNi0.5Mn1.5O4 composite with improved high temperature performance as a cathode material for Li-ion batteries

To investigate the effect of Ce doping on structure and the electrochemical properties of spinel LiNi0.5Mn1.5O4, especially the cycling performance at high temperature, spinel cathode materials LiNi0.5-0.5xMn1.5-0.5xCexO4 (x = 0, 0.01, 0.02, 0.03) were prepared by the sol-gel method for use in lithium ion batteries. For this purpose a half-cell was assembled with a lithium metal anode and a full-cell was paired with graphite. The characterization and analysis of the prepared LiNi0.5-0.5xMn1.5-0.5xCexO4 (x = 0, 0.01, 0.02, 0.03) composites revealed that all of the samples had a disordered spinel octahedron structure, and that the purity of the phase increased after appropriate Ce doping. Compared to the pristine sample, the prepared LiNi0.495Mn1.495Ce0.02O4, (x = 0.02) had outstanding electrochemical performance with an initial capacity of 133.8 mAh/g, and 131.9 mAh/g at 1 C and 55 °C after 50 cycles, and maintained a capacity retention value of 98.6% at 1 C and 25 °C at the 100th cycle. The introduction of Ce as dopant improved the electrochemical performance of LiNi0.5Mn1.5O4 as a result of the synergistic effects of stronger structural stability, higher lithium ion diffusion coefficient, and lower electrochemical polarization.