Advanced carbon electrode for electrochemical capacitors

Electrochemical capacitors are high-power energy storage devices having long cycle durability in comparison to secondary batteries. The energy storage mechanisms can be electric double-layer capacitance (ion adsorption) or pseudocapacitance (fast redox reaction) at the electrode-electrolyte interface. Most commonly used electrode materials are carbon materials with high specific surface area, microporous-activated carbons. A considerable number of studies have been conducted to optimize the pore structure and surface functionalities of activated carbons. In addition to conventional activated carbons, other types of carbon materials such as carbon aerogel/xerogel, templated carbons, carbide-derived carbons, carbon nanotubes, and graphene-based materials have been investigated. This review highlights the key features of advanced carbon materials for application to commercial capacitor devices.