Nanostructured Carbons: Double-Layer Capacitance and More

The Electrochemical Society Interface • Spring 2008 This article is concerned with the design and characteristics of electrochemical double layer capacitors (EDLCs), and in particular the role of nanostructured carbons and how they function. EDLCs have been under development for over 20 years, but it is only relatively recently that the mechanisms of energy storage in carbon film electrodes have been studied in depth and the relationships between the carbon properties and specific capacitance (F/gm) have been quantified. The first section of this article is devoted to a discussion of the double-layer energy storage mechanisms and several important recent findings that begin to explain the relationship between the pore characteristics of the carbon and specific capacitance. The later sections of the article are concerned with the present characteristics (energy density and power capability) of EDLCs using nanostructured carbons and what further improvements in device performance are likely in the future.