High-nickel material is a high energy density cathode. However, its practical application is hindered by the structure and surface instability that cause severe capacity fading during cycling. In this study, a one-step approach of AlPO4 modification to create Li3PO4-LiAlO2 coating layer on LiNi0.8Co0.1Mn0.1O2 cathode materials is reported. The Li3PO4-LiAlO2 protective coating can not only mitigate the structure degradation near the surface, but also protect from the attacking of HF and H2O to the bulk surface. The AlPO4-modified materials exhibit excellent electrochemical properties, where its initial discharge capacity is up to 190.2 mAh g−1 at 1C over 3.0–4.4 V, and the corresponding retention after 100 cycles also increases to 96.42%. Overall, this work offers some meaningful insights on addressing the structure and surface instability, and enhancing the properties of high-nickel materials, which can be of great importance for the further development and commercialization of high-nickel materials.