The electrochemical performance of LiNi0.8Co0.15Al0.05O2 (NCA) is investigated to be improved by coating with Co3O4 via a facile and efficient preparation method. The transmission microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements show that the Co3O4 layer is successfully coated on the surface of NCA cathode material. Notably, the 0.3 wt% Co3O4-coated NCA cathode material provides a high capacity retention of 95.2% at 1C between the potential from 2.7 to 4.3 V after 60 cycles, which is higher than the corresponding value of 86.1% for the bare NCA sample. In addition, Co3O4-modified NCA cathode material possesses high rate capability. It showed discharge specific capacity of 163 mAh g−1 at 5C rate, whereas the bare NCA sample only exhibits 141 mAh g−1. The Co3O4 coating layer can suppress the direct contacting and reaction between NCA and the electrolyte, thus enhancing the cycling stability of NCA. Moreover, Co3O4 can react with residual Li2CO3/LiOH on the surface of NCA and decrease the charge-transfer resistance, which improve the rate capability.