The effect of barium hydroxide on the rechargeable performance of alkaline y-MnO₂

A series of controlled current cycling experiments have been conducted to investigate the effect of barium hydroxide on the rechargeable performance of the alkaline manganese dioxide cathode. Analysis of the resulting discharge behavior revealed that the inclusion of Ba(OH)₂ suppresses the dissolution of Mn³⁺ ions during the latter stages of discharge. This in turn gave rise to improved rechargeable performance, with electrodes containing Ba(OH)₂ exhibiting both improved capacity retention and higher cumulative capacities. Similar effects were observed during the cycling of manganese dioxide in the presence of soluble Ba(II) ions, and the implications in terms of its underlying role considered. In both cases barium hydroxide was also noted to inhibit the formation of δ-MnO₂, and this was confirmed by X-ray diffraction and transmission electron microscopy.