Electronically Conductive Sb-doped SnO2 Nanoparticles Coated LiNi0.8Co0.15Al0.05O2 Cathode Material with Enhanced Electrochemical Properties for Li-ion Batteries

Abstract

The LiNi0.8Co0.15Al0.05O2 (NCA) cathode material is modified by electronically conductive antimony-doped tin oxide (ATO) nanoparticles via a facile wet chemical process. As observed by scanning and transmission electron microscopy, the ATO nanoparticles are homogeneously coated on the surface of NCA material. Thus-obtained ATO-coated NCA (ATO-NCA) material delivers a high discharge capacity of 145mAhg−1 at the current rate of 5C, which is significantly higher than that of pristine NCA material (135mAhg−1). Moreover, the capacity retention of ATO-NCA material is 91.70% after 200 cycles at the current rate of 1C and 60°C. In contrast, the pristine NCA only maintains 70.89% of its initial capacity after the same cycles. The substantially improved cyclability and rate capability are mainly attributed to the ATO coating layer, which can not only enhance the electron transport but also effectively restrain the side reactions between the NCA material and the electrolyte. More specifically, X-ray diffraction and photoelectron spectroscopy reveal that the ATO coating layer can restrain the Li+/Ni2+ disordering and the growth of SEI layer of NCA material, which are responsible for the improved cycling stability, especially at elevated temperatures.