Enhanced cycling performance of spinel LiMn2O4 coated with ZnMn2O4 shell

Abstract

ZnMn2O4 shell-coated LiMn2O4 was prepared by a simple routine that the mixture of LiMn2O 4 and ZnO were heated at 750 °C. The structure and electrochemical performance of as-prepared powder compared with the pure LiMn2O4 were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDAX), and galvanostatic charge-discharge testing, respectively. The results of XRD, SEM, and EDAX show that ZnMn2O4 is formed on the surface of LiMn2O4 particles. Charge-discharge testing reveals that ZnMn2O4 shell-coated LiMn2O4 greatly enhances the capacity retention of the spinel LiMn2O4. Furthermore, the modified LiMn2O4 shows significant enhancement in cycling stability at rates from 0.5 C to 12 C. It is found that the improved cycling performance and rate capability of the modified LiMn 2O4 are attributed to the effective decrease of manganese dissolution from spinel structure because of ZnMn2O4 shell coated on the surface of LiMn2O4 particle. © 2007 Springer-Verlag.