Investigation and improvement on the electrochemical performance and storage characteristics of LiNiO2-based materials for lithium ion battery

Poor storage property and the rapid moisture hinder the application of LiNi0.8Co0.1Mn0.1O2 due to the formation of Li2CO3/LiOH impurities and a spontaneous reduction of Ni3+ to Ni2+ on the surface. Alcohol washing is desirable to improve the electrochemical performance, storage characteristics and structural stability of LiNi0.8Co0.1Mn0.1O2. Electrochemical studies indicate that washed material exhibits a higher discharge capacity (148 mAh g(-1) at 8 C) and better capacity retention at 2 C (79.2% after 100 cycles) compared with the un-treated material after storage in air for 40 days. Inductively coupled plasma (ICP) tests show the amount of metal dissolution decreases compared with the un-washed sample. The Rietveld refinement results indicate that the Li/Ni cationic disorder can be reduced from 0.0714 to 0.0538 by alcohol washing after storage. Transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) indicate alcohol washing contributes LiNi0.8Co0.1Mn0.1O2 much resistant to H2O and CO2, which further reduce the formation of Li2CO3 and maintain structural stability during the storage process. (C) 2016 Published by Elsevier Ltd.