The invention provides a preparation method of manganous-manganic
oxide and the manganous-manganic
oxide. The preparation method comprises the following steps of adjusting the pH value of
manganese dioxide
powder slurry to be 2.0-2.5, stirring the
slurry at the temperature of 60-70 DEG C and conducting
solid-liquid separation; adding
manganese dioxide after scouring in
manganese sulfate solution with the concentration of 100-200g / L; warming the solution at
nitrogen atmosphere to the temperature in the scope of 55-60DEG C; leading in NH3 holding solution with the pH value in the scope of 7.5-8.0, and maintaining, stirring and reacting for 0.8-1.2 hours after the pH value of the holding solution is stable; replacing
nitrogen atmosphere by using
oxygen atmosphere, leading in NH3 holding solution with the pH value in the scope of 7.0-7.5, adding 250-350g / L of MnSO4 solution, reacting until concentration of Mn+ is smaller than 500ppm, stopping the reaction, conducting
solid-liquid separation, washing
solid phase, and
drying to obtain globular Mn3O4 products. The preparation method can use electrolytic manganese dioxide (EMD)
tail powder to serve as raw materials, obtained manganous-manganic
oxide products are approximately spherical and high in purity, and requirements for
lithium-
ion secondary battery are met.