Framework Doping of Cobalt into Layered Manganese Oxide for Improved Capacitive Behavior

Anodic deposition of layered manganese oxides has been carried out at various bath temperatures in the presence of cobalt ions. Crystallinity of the layered Mn oxide increased with increasing the bath temperature. In the deposition of the layered Mn oxide, Co2+ ions were not involved at room temperature, while at 70 degrees C the presence of Co2+ exhibited a catalytic current suggesting the formation of Mn and Co composite. Addition of Co2+ did not provide any new diffraction peaks but caused broadening of the peaks due to Mn oxide. This indicates the introduction of Co ions into the Mn oxide sheets. Doping of Co into the Mn oxide framework caused a drastic increase in the specific capacitance.