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Improved Energy Storage


John Chmiola, an alumnus of the Drexel/Penn IGERT Traineeship in Nanoscale Science & Engineering, has published his second paper as first author in Science on April 22, 2010 ( – J. Chmiola, C. Largeot, P.-L. Taberna, P. Simon, and Y. Gogotsi, “Monolithic carbide-derived carbon films for micro-supercapacitors”).

The paper is based on Chmiola’s PhD research and describes a new method of producing supercapacitors that doubles their performance over similar devices reported thus far. The research also presents an opportunity for integrating supercapacitors with electronic devices such as cell phones and laptop computers.

Previous studies by this group used porous carbon called carbide derived carbon (CDC) in powdered form as the electrode material. That work was also published in Science in 2006, and led to a feature on NSF’s main Web site banner and in the Discoveries section. The technology was licensed by Drexel University to its start-up company Y-Carbon, and devices are being made using the materials developed during Chmiola’s PhD research.

The innovation reported here is the use of monolithic “bulk” films with no macroporosity. The team took some cues from the microelectronics industry, starting with conductive TiC substrates, then etching a very thin electroactive layer (Ti-CDC) to store charge.

By using microfabrication-type techniques, Chmiola and colleagues avoided many of the pitfalls of the “sandwich” method, such as poor contact between electroactive particles in the electrode; large void space between the particles, which contributes significantly to mass and volume because it is filled with electrolyte, but does not store charge; and poor contact with the materials that carry electrons out of the electroactive materials and to the external circuitry.

Address Goals

This research advances the frontiers of knowledge in energy storage, a field that has huge potential benefit. Transfer of this technology to a small but growing start-up company will also mean an increase in green jobs.