A multifunctional silicotungstic acid-modified Li-rich manganese-based cathode material with excellent electrochemical properties

Abstract

Li-rich layered oxide (LrLO) cathode has attracted much attention for Li-ion batteries in recent years due to its superior capacity of exceeding 250 mA h g−1. However, these materials still have some inherent drawbacks such as poor rate stability and cycle performance. In this paper, Li-rich cathode material Li1.2Mn0.54Ni0.13Co0.13O2 was modified by silicotungstic acid (HSW) with high electronic and ionic conductivity via a facile approach. The material was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and electrochemical tests. The results showed that the thickness of HSW coating was about 5 nm. HSW coating could supply a transfer pathway for Li ions and electrons, resulting in the superior discharge capacity and rate capability. The HSW-LrLO could deliver 158.38 mA h g−1 even at high current density of 500 mA g−1, which was 26.9% higher than that of pristine LrLO. In addition, HSW-LrLO exhibited excellent cycling performance with the capacity retention over 90% at 1 and 5 C. These results were useful to develop effective surface modification for LrLO materials.