The precursor was treated by KMnO4 and combined with the formation of single crystal primary particles to improve the electrochemical performance of LiNi0.8Mn0.1Co0.1O2 in this study. The single crystal primary morphology of the cathode material can not only shorten the migration path of lithium ions, but also maintain the integrity of particle morphology and avoid the generation of cracks in particles after circulation. Some Mn4+ from KMnO4 incorporated into the crystal lattice, causing a small amount of Ni2+ act as pillars in the lithium layer and thus avoiding its collapse in the delithium state. Besides that, a thin MnO2 layer is also formed on the cathode material, which inhibit side reactions between electrolyte and cathode material. The results show that the synergistic coupling effects of single crystal morphology and precursor treatment are realized to improve the electrochemical properties of the Ni-rich cathode materials. Display omitted •MnO2 layer improves interface stability between cathode material and electrolyte.•The side decomposition of LiPF6 and electrolyte has been suppressed.•Mn-doped into the cathode material triggers partial Ni3+ reduction to Ni2+.•Ni2+ migrate to lithium layer which prevent interslab collapse during cycling.•The single crystal morphology inhibits the generation of cracks during cycling.