Li-rich Mn-based Co-doped Li1.231Mn0.615-0.75xNi0.154CoxO2 (x = 0, 0.02, 0.05, 0.07, 0.10, 0.12, 0.15, 0.20, 0.25) cathode materials were prepared by a facile combustion method. X-ray diffraction analysis indicates that the crystal structure of materials has been modified by the doped cobalt ions. The capacity differential results obtained from the galvanostatic charge-discharge process within 2.0 and 4.8 V (vs. Li/Li+) indicate that the cobalt doped in the material could conduce to lithium ions re- embedded into the structure and increase the electrical properties. Compared with the electrochemical properties of these materials, the optimum doped sample is Li1.231Mn0.525Ni0.154Co0.12O2 (x = 0.12), which delivers an extreme minimum irreversible capacity of 59.1 mA h g(-1) with the highest coulombic efficiency of 82.6%, and its discharge specific capacity maintains 180.7 mA h g(-1) at 1 C rate after 50 cycles.