A new porous carbon “sponge” that could be used for energy-storing supercapacitors in everything from electric cars to smart grids has been created by Rodney Ruoff and colleagues at the University of Texas at Austin.

They created the carbon sponge by using microwaves to exfoliate graphite oxide, then treating the product with potassium hydroxide to create tiny holes separated by walls just a single atom thick.

They found that the substance has 3,100 square meters of surface area per gram — roughly half of a football field. According to Ruoff, this could be useful for holding a large amount of electrolyte, which in turn can hold a large electrical charge. The sponge itself can conduct electricity, providing an efficient way for electricity to flow into and out of the electrolyte.

Unlike batteries, capacitors and supercapacitors can only store charge for a short time, but are able to quickly discharge high amounts of electrical energy. According to Ruoff’s colleague, Yanwu Zhu, the new sponge will allow supercapacitors to deliver significantly more charge than previous supercapacitors.

Ref: Yanwu Zhu, Shanthi Murali, Meryl D. Stoller, K. J. Ganesh, Weiwei Cai, Paulo J. Ferreira, Adam Pirkle, Robert M. Wallace, Katie A. Cychosz, Matthias Thommes, Dong Su, Eric A. Stach, and Rodney S. Ruoff, Carbon-Based Supercapacitors Produced by Activation of Graphene, Science, Published online 12 May 2011 [DOI:10.1126/science.1200770]