Zinc-manganese dioxide galvanic cell using zinc sulphate as electrolyte. Rechargeability of the cell

The discharge capacity of the Zn|ZnSo4(aq)|MnO2 galvanic cell increases with increase in the concentration of ZnSO4; use of a 2 M aqueous solution of ZnSO4 gives 65% utilization of MnO2. When the cell is charged after discharging, X-ray diffraction analysis of the positive electrode material indicates regeneration of γ-MnO2 during the charging. Repeated charging and discharging under various modes reveals that the cell is rechargeable more than 30 times. When the cell is charged to 1.70V and discharged to 0.9V, the cell shows about 100% coulombic efficiency with an average discharging voltage of about 1.3V (energy efficiency=83%) and 57% utilization of MnO2. The cell is rechargeable after discharging to 0V.