Superior electrochemical properties of Zirconium and Fluorine co‐doped Li1.20[Mn0.54Ni0.13Co0.13]O2 as cathode material for lithium ion batteries

Abstract

In the paper, the Zr4+ and F− co-doping was employed to expectedly improve the rate performance and structure stability of Li1.20[Mn0.54Ni0.13Co0.13]O2. The effects of Zr4+ doping and F− doping on the micro-structure, cathode morphology and element chemical state were investigated by XRD, Rietveld refined XRD, SEM, TEM, and XPS. It indicated the Zr4+ and F− were inserted into the cathode crystal structure with ideally designed. Besides, the electrochemical characterization confirmed that the cathode after the Zr4+ or/and F− doping delivered the superior electrochemical properties when compared to the pristine one. Firstly, the Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 could express a high discharge capacity of 132.6 mAhg−1 at 5C rate, which was 40.1 mAhg−1 larger than that of the pristine one (92.5 mAhg−1). In addition, the Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 remained a capacity retention of 90.7% after 100 cycles at 2C rate and with the 148.2 mAh g−1 left. While the bare cathode delivered an initial discharge capacity of 134.1 mAhg−1 at 2C rate, then dramatically attenuated to 108.7 mAhg−1 after 100 cycles with the capacity retention of 81.1%. The enhanced electrochemical properties of Li1.20[Mn0.52Ni0.13Co0.13Zr0.02]O1.95F0.05 was mainly put down to the suppression of charge transfer resistance increase by the Zr4+ and F− doping modification along with cycles.