This invention relates to a method for covering alkyl Co2O on the surface of Ni(OH)2 including: 1, stocking: preparing Co2SO4: 0.5-2mol/L, NaOH solution:3-8mol/L, ammonia:6-10mol/L, 2, adding one portion of ball Ni(OH)2 in a reaction kettle with 6-12 portions of deionized water in it already to be mixed and control the temperature at 30-70deg.C, then adding 1 of Co2SO4 solution, 2-2.5 of NaOH solution and 0.8-1.5 ammonia in a reaction kettle to be reacted for 3-8 hours with the PH value at 10-11, then stopping feeding in the Co2SO4 solution and adding NaOH solution so that the PH value rises to 12-13.6, then adding chloros in 1-5% weight of Ni(OH)2 after the temperature rises to 80-90deg.C to be mixed for 30-60 minutes, 3, carrying out separation of the solid and liquid to be dried. |