LiNi1/3Co1/3Mn1/3O2 (NCM) is a promising cathode material for lithium-ion battery. In this research, a facile co-precipitation process is employed, during which the mixed solution of NH3·H2O, H2O2 (30% aqueous solution) and LiOH·H2O is added into the nitrate solution. Notably, H2O2 is introduced as the oxidant and dispersant during the co-precipitation process to oxidize the metal ions and decrease the agglomeration of the precursor by giving out O2, and then improves the specific capacity, stability and energy density of NCM. Additionally, O3 is employed to further oxidize NCM to enhance the stability during the calcination process. The obtained NCM material with single crystal structure exhibits a high initial discharge specific capacity of 208.9 mAh g−1 at 0.1 C (1 C = 280 mA g−1), an excellent cycle stability with high retained capacity of 176.3 mAh g−1 after 50 cycles, and a high initial discharge specific capacities of 150.6 mAh g−1 at 5 C even at a high cutoff potential (4.6 V).