Facile synthesis of nanostructured MoO3 coated Li1.2Mn0.56Ni0.16Co0.08O2 materials with good electrochemical properties

Abstract

Li_1.2Mn_0.56Ni_0.16Co_0.08O₂ cathode materials were synthesized by a co-precipitation method. The secondary particles consisted of mainly nanorods and nanoplates that expose electrochemically active crystal surfaces. The rate performance and cycling stability of the cathode materials were remarkably enhanced after MoO₃ coating using the molten salt method. Particularly, the 1 wt%-MoO₃ coated materials deliver the highest discharge capacity of 217 mA h g⁻¹ at 1C rate and a retention higher than 91.5% after 100 cycles. The structure of the material was investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and Raman spectroscopy. The results show remarkable phase transformation from a layered structure to spinel structure at the surface of the cathode material after MoO₃ coating, while the bulk structure remained unchanged. The improved cycling stability and the rate performance are ascribed to the formation of the spinel structure at the surface.