Enhanced electrochemical performance of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode material coated with Li + -conductive Li 2 SiO 3 for lithium ion batteries

Abstract Materials of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 coated with different amounts of Li + -conductive Li 2 SiO 3 (1.5, 3.0, 4.5 wt%) were synthesized through an isochronous lithium source method. The structures and morphologies of all samples exhibited no apparent changes after being coated with Li 2 SiO 3 . Electrochemical tests demonstrated that the initial Coulombic efficiency, cycle capacity retention and rate performance were improved. Especially for the 3 wt% Li 2 SiO 3 - coated sample, its initial Coulombic efficiency was increased by 5.2% (81.3%) compared with the pristine state (76.1%). After 100 cycles at 1 C, it maintained a discharge capacity of 142 mAh g −1 with the retention of 85.1%, which is much better than the bare Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (121.9 mAh g −1 and 77.5%). In addition, the rate performance was also greatly enhanced under high current density. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) suggested that the enhanced electrochemical performance mainly benefited from the protective function of the coating layer of Li 2 SiO 3 and its three-dimensional path for Li + transmission in the structure, which would stabilizes the structure and accelerates the rate of Li + migration respectively.