Serendipitous supercapacitors

The unexpected discovery of a new three-dimensional porous carbon material could allow supercapacitors to rival the performance of the standard lead-acid battery.

A group at the University of Texas in Austin were trying to make activated carbon with a standard method involving potassium hydroxide. Biomass is the usual carbon source for this process in industry, but the Austin group used graphitic carbon instead, with surprising results. Rather than produce a simple structure full of holes, they instead found that dilute amounts of the potassium hydroxide had restructured the carbon into a three-dimensional network with a very high surface area1.

Dr Rodney Ruoff and his colleagues tested their carbon material for use as a supercapacitor and found that it performed surprisingly well, particularly with ionic liquid electrolytes which function over a much larger voltage range. These properties mean that capacitors made from this new carbon material could charge the same amount of energy much faster than a standard lead-acid battery. The method of making these porous carbon materials is also cost-effective and would be straightforward to commercialise, and has the additional potential to be modified to form other three-dimensional graphene-based structures2.

Written by Stephanie Boardman

  1. Zhu, Y., Murali, S., Stoller, M.D., Ganesh, K.J., Cai, W., Ferreira, P.J., Pirkle, A., Wallace, A.M., Cychosz, K.A., Thommes, M., Su, D., Stach, E.A. & Ruoff, R.S. 2011. Carbon-based supercapacitors produced by activation of graphene. Science 2011, DOI: 10.1126/science.1200770 []
  2. http://www.rsc.org/chemistryworld/News/2011/May/13051102.asp []