Journal of Materials Research


Curvature effects in carbon nanomaterials: Exohedral versus endohedral supercapacitors

Jingsong Huang c1, Bobby G. Sumpter, Vincent Meuniera1, Gleb Yushina2, Cristelle Portet and Yury Gogotsia3 c2

a1 Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6367

a2 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245

a3 Department of Materials Science and Engineering, A.J. Drexel Nanotechnology Institute, Drexel University, Philadelphia, Pennsylvania 19104


Capacitive energy storage mechanisms in nanoporous carbon supercapacitors hinge on endohedral interactions in carbon materials with macro-, meso-, and micropores that have negative surface curvature. In this article, we show that because of the positive curvature found in zero-dimensional carbon onions or one-dimensional carbon nanotube arrays, exohedral interactions cause the normalized capacitance to increase with decreasing particle size or tube diameter, in sharp contrast to the behavior of nanoporous carbon materials. This finding is in good agreement with the trend of recent experimental data. Our analysis suggests that electrical energy storage can be improved by exploiting the highly curved surfaces of carbon nanotube arrays with diameters on the order of 1 nm.

(Received January 15 2010)

(Accepted February 22 2010)

Key Words:

  • Energy storage