Electrosynthesis of manganese dioxide with gamma crystal structure as active material of alkaline battery cathode

γ-phase manganese dioxide (EMD) is used widely as cathode material in alkaline batteries, lithium-manganese batteries, metal-air batteries, and supercapacitors. Low production cost, environmental friendliness, high redox potential, high current rate capability, good temperature range, and long storage life, despite its limitations in achieving theoretical power density and practical charging capability are the most important advantages of EMD. The theoretical discharge capacity of EMD is equal to 308 mAh g-1 which is related to its single electron discharge stage. In this research, the electrosynthesis of the EMD active material has been conducted using the constant current electrolysis method in an acidic bath of manganese sulfate and sulfuric acid. The temperature of the acidic bath is equal to 95 ̊C and the current density is 10 mA cm-2. In this method, after electrolysis, the formed EMD on the anode surface is mechanically separated, crushed, washed, neutralized and then dried. In the constant current electrolysis method, a multi-electrode system is used to improve the current efficiency. Anode substrate is titanium and cathode material is graphite. X-ray diffraction results show that the provided powder is in the form of γ phase and the current efficiency is 93.75%.