High Surface Area Carbon Electrodes for Electrochemical Double Layer Capacitors

A novel method for preparing carbon electrode structures having applications in electrochemical double layer capacitors (EDLCs) is described. The method for preparing these structures employs carbon (graphite) nano fiber materials and results in an electrode having both high surface area and high electronic conductivity; two essential characteristics for EDLC electrodes. The fabrication process allows the electrochemically active surface area, as well as, the crystallographic orientation of graphite crystallites to be controlled. Additionally, the resulting structure may require no internal current collector, thus allowing DLC devices made from these materials to achieve high specific capacitance. The "binder" used to prepare the structures is compatible with the carbon fiber materials and also contributes to the capacitance. A novel activation process is also used to achieve high specific capacitance in the finished electrode structure. By controlling the various process variables, it may be possible to tailor electrodes and ultimately DLC devices to specific applications. Microstructural and physiochemical characterization of the electrode materials will be performed. The electrochemical characteristics of finished electrode materials will be evaluated in assembled DLC devices.