Manganese carbonate as active material in potassium carbonate electrolyte

In this work, we explore the possibility of using MnCO 3 as active material for alkaline rechargeable batteries. K 2 CO 3 solution is chosen as electrolyte because the solubility of MnCO 3 in K 2 CO 3 electrolyte keeps lower than that in KOH electrolyte of the same pH values, which may promote the cyclability of MnCO 3 . XRD and XPS measurements reveal a two-electron transfer reaction during cycling, corresponding to the conversion of MnCO 3 /MnO 2 . Further investigations demonstrate the MnCO 3 electrode can be cycled 50 cycles without obvious capacity decay and the coulombic efficiency keeps over 95.0% after the 8th cycle. The present study provides a new perspective in searching new electrode materials and electrolyte systems for alkaline rechargeable batteries.