Effect of diffuse layer and pore shapes in mesoporous carbon supercapacitors

Journal Article · Fri Jan 01 04:00:00 EST 2010 · Journal of Materials Research

DOI:https://doi.org/10.1557/jmr.2010.0188· OSTI ID:986414

Huang, Jingsong ^[1]; Sumpter, Bobby G ^[1]; Meunier, Vincent ^[1]; Qiao, Rui ^[1]

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1. ORNL

In the spirit of the theoretical evolution from the Helmholtz model to the Gouy Chapman Stern model for electric double-layer capacitors, we explored the effect of a diffuse layer on the capacitance of mesoporous carbon supercapacitors by solving the Poisson Boltzmann (PB) equation in mesopores of diameters from 2 to 20 nm. To evaluate the effect of pore shape, both slit and cylindrical pores were considered. We found that the diffuse layer does not affect the capacitance significantly. For slit pores, the area-normalized capacitance is nearly independent of pore size, which is not experimentally observed for template carbons. In comparison, for cylindrical pores, PB simulations produce a trend of slightly increasing area-normalized capacitance with pore size, similar to that depicted by the electric double-cylinder capacitor model proposed earlier. These results indicate that it is appropriate to approximate the pore shape of mesoporous carbons as being cylindrical and the electric double-cylinder capacitor model should be used for mesoporous carbons as a replacement of the traditional Helmholtz model.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences
• Sponsoring Organization: ORNL LDRD Director's R&D; SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 986414
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 8 Vol. 25; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CAPACITANCE
CAPACITORS
CARBON
SHAPE