Enhanced Electrochemical Properties of Lithium‐Rich Cathode Materials by Magnesium Borate Surface Coating

Abstract Magnesium borate oxide (MBO) coated lithium‐rich layered Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 particles are synthesized via a wet chemical coating method. The X‐ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and X‐ray photoelectron spectrometer results indicate that the cathode particles are uniformly covered with a MBO layer. The results of charge/discharge tests show that the MBO‐coated electrode has enhanced electrochemical properties both in rate capability and cycling stability compared to the bare one. Specifically, 3 wt. % MBO‐coated sample has capacity retention of 98.3 %, much more than the bare one of only 79.2 % after 100 cycles at 1 C. Furthermore, the MBO‐coated electrode retains a superior high‐rate capacity of 90 mAh g −1 at 10 C. The remarkably enhanced rate capability and cycling stability of MBO‐coated electrode is ascribed to the MBO coating layer efficiently isolating the bulk Li 1.2 Mn 0.54 Co 0.13 Ni 0.13 O 2 from direct contact with the electrolyte, and facilitating both charge transfer reaction and the kinetics of lithium ion diffusion through the surface layer.