Effect of metal ion concentration in precursor solution on structure and electrochemical performance of LiNi0.6Co0.2Mn0.2O2

Abstract

LiNi0.6Mn0.2Co0.2O2 (622NCM) cathode materials are synthesized by a carbonate co-precipitation process. We decomposed Co and Mn carbonates to form porous CoMnO3 precursors, which were impregnated with Ni and Li salts to form final materials. To provide better hosts for the Ni and Li salts, we design the co-precipitation solutions with different total metal ion concentrations to achieve precursors with stable structures and appropriate porosity. We obtained 622NCM with hierarchical and porous properties, which shortened the lithium ion transmission distance and improved the electrolyte infiltration rate and rate capability. Furthermore, our 622NCM cathode materials showed no loss of thermodynamic or electrochemical stability during cycling. The most suitable concentration was determined to be 0.03 mol L−1 and the as-prepared 622NCM (0.03–622NCM) cathode material exhibited good cycle reversibility, a high capacity, and good rate capability, delivering a discharge capacity of 152 mA h g−1 at 0.2 C. A capacity of more than 100 mA h g−1 was achieved at a high rate of 5 C. This study provides guidance for preparing nickel-rich ternary cathode materials for high-performance lithium-ion batteries.