LiNi0.5Mn0.3Co0.2O2 (NMC) cathode material is surface treated by Li active boron oxide (LBO) via a two-step process. The surface morphology, crystal structure, surface composition, and electrochemical properties were characterized based on SEM, XRD, XPS, charge–discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) measurements. XPS results showed that the coating layer was composed of LiBO2. The 2 wt% LBO-coated NMC exhibited the best electrochemical performance at high voltage (4.5V). It was achieved a high capacity retention of 91.23% after 50 cycle which was 53.19% for the uncoated one. The rate capability of the coated electrode was improved obviously, exhibiting 114.71 mAh·g-1 discharge capacity at 10C. The interfacial resistance and charge transfer resistance was also decreased owning to the fact that the coating layer played a “firewall” between the electrolyte and the NMC electrode.