A manganese-doped barium carbonate cathode for alkaline batteries

MnO₂-Zn alkaline batteries are one of the most common modern forms of primary battery, due to their relatively high energy density and low cost per kilowatt-hour. Additionally, unlike many other types of primary battery, alkaline cells can theoretically be recharged. Their low cost per kilowatt-hour makes them potentially ideal for applications such as sustainable energy storage or peak demand shaving. However, a phase transformation that occurs in MnO₂ after reduction by more than one electron converts it into the electrochemically inactive Mn₃O₄ phase. This limits the total depth of discharge of the cell significantly.We report the synthesis of a novel electrode material, manganese-doped witherite, for rechargeable alkaline batteries produced by a simple hydrothermal process. The material has been studied via X-ray diffraction and electroanalytical techniques. We show that unaltered witherite has poor electrochemical properties, and that this new material has high capacity and rate capability, even under deep discharge conditions, superior to conventional manganese dioxide.