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.