Improving the electrochemical performance of LiNi0.5Mn1.5O4 by ZnO nanocrystals coating

Abstract

The cathodic material LiNi0.5Mn1.5O4 was produced by the Solution Combustion Synthesis method (SCS). The as-made crystalline nanoparticles were annealed at 900 °C, obtaining micron-sized particles, and then coated with ZnO nanocrystals at a weight relation between 0.5 and 2.5 wt%, also using the SCS method. The nanocrystalline porous coating was confirmed by XRD, SEM and TEM. Electrochemical measurements verified that all materials coated with ZnO nanoparticles improved their electrochemical properties concerning the uncoated material, preventing degradation over the cycles, and stability along cyclic voltammetry cycles. It was observed that a 1 wt% ZnO coating presents the best improvement in discharge capacity and rate capability, and that the charge transfer resistance of the coated material is reduced to 1/3 of the uncoated one after 100 electrochemical cycles. In this work, the simple, time and energy saving SCS method was verified to obtain nanoshell-coated LNMO microparticles with improved electrochemical performance.