Improved electrochemical performance of 5 V spinel LiNi0.5Mn1.5O4 by La2O3 surface coating for Li-ion batteries

LiNi0.5Mn1.5O4 coated with 1.5 wt.% La2O3 was prepared and investigated as cathode materials for lithium ion batteries. The samples was characterized by XRD, SEM and EDX. After the 1.5 wt.% La2O3 coating, the lattice structure of LiNi0.5Mn1.5O4 is not destroyed and a La2O3 coating layer has formed on the surface of LiNi0.5Mn1.5O4 particles. The 1.5 wt.% La2O3-coated LiNi0.5Mn1.5O4 exhibits a higher rate capacity, with discharge capacity between 3.5 and 5 V of 131.9, 127.1, 126.5, 120.7, 114.1 and 101.5 mAh g-1 at rates of 0.2, 0.5, 1, 2, 3 and 5 C (1 C = 140 mAh g-1), respectively. The results indicate that the La2O3 coating could reduce the electrode polarization and enhance the rate capacities