2.4 V All‐Manganese Aqueous Rechargeable Cell

Abstract We report the construction of 2.4 V aqueous manganese dioxide (MnO 2 )|manganese (Mn) rechargeable cell, not needing the combination of cation and anion exchange membranes and a third electrolyte chamber. This novel designs using Mn metal as negative electrode and MnSO 4 acidic solution as electrolyte, avoids the side reactions of MnO 2 −Zn batteries in alkaline electrolyte and exhibits 2.1 V operating voltage and 87.8 % of MnO 2 ’s theoretical one‐electron capacity (308 mAh/g) at C/6 rate. After charging and discharging continuously for 100 cycles at 50 % charge depth of MnO 2 , the capacity retention rate is still 89.2 %.