Electrochemical Double Layer Capacitance in Activated Carbon: Ion Size Effects

Supercapacitors are ideal devices for rapid storage and release of energy. They can provide an electrical energy buffer between a rapidly changing load and a battery or fuel cell which work best under steady state conditions. Activated carbon is an important substrate for many of the commercially available double layer supercapacitors. Despite the research and commercialization work that has been carried out, there is still a need to understand some of the fundamental characteristics of the role of activated carbon in the double layer charging. The effect of cation size in an aqueous electrolyte on capacitance was investigated. The results showed capacitance decreased with hydrated ion size for an activated carbon with a significant micropore surface area.