Discharge behaviour has been determined at 25 for the characterization of the manganese dioxides produced by ozone oxidation in acidified manganese (II) sulfate solutions at a constant ozone partial pressure, 2×10-2 atm. A descent of the manganese dioxide electrode potential with discharge time was measured in 9.0mol/l KOH solution at a constant applied current of 2.0mA/0.10g MnO2.
The manganese dioxides, identified as gamma type according to X-ray diffraction data, showed discharge characteristics analogous to the electrolytic manganese dioxide for battery use. The observed discharge behaviour of the manganese dioxides was found to be significantly influenced by ozonation conditions, reaction temperature, from 25 up to 80°C, and acid concentration of the solution up to 5.0 mol/l.
The manganese dioxides formed at temperatures above 60°C in solutions of acid concentration of 0.5 to 1.5 mol/l possess the discharge capacity larger than some typical electrolytic manganese dioxide samples. Similar discharge curves were observed also for the manganese dioxide precipitated from the solutions simulating zinc sulfate electrolyte solution.
