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Relation between the Ion Size and Pore Size for an Electric Double-Layer Capacitor.

Largeot, Céline and Portet, Cristelle and Chmiola, John and Taberna, Pierre-Louis and Gogotsi, Yury and Simon, Patrice Relation between the Ion Size and Pore Size for an Electric Double-Layer Capacitor. (2008) Journal of American Chemical Society, 130 (9). 2730-3731. ISSN 0002-7863

(Document in English)

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Official URL: http://dx.doi.org/10.1021/ja7106178


The research on electrochemical double layer capacitors (EDLC), also known as supercapacitors or ultracapacitors, is quickly expanding because their power delivery performance fills the gap between dielectric capacitors and traditional batteries. However, many fundamental questions, such as the relations between the pore size of carbon electrodes, ion size of the electrolyte, and the capacitance have not yet been fully answered. We show that the pore size leading to the maximum double-layer capacitance of a TiC-derived carbon electrode in a solvent-free ethyl-methylimmidazolium-bis(trifluoro-methane-sulfonyl)imide (EMI-TFSI) ionic liquid is roughly equal to the ion size (0.7 nm). The capacitance values of TiC−CDC produced at 500 °C are more than 160 F/g and 85 F/cm3 at 60 °C, while standard activated carbons with larger pores and a broader pore size distribution present capacitance values lower than 100 F/g and 50 F/cm3 in ionic liquids. A significant drop in capacitance has been observed in pores that were larger or smaller than the ion size by just an angstrom, suggesting that the pore size must be tuned with sub-angstrom accuracy when selecting a carbon/ion couple. This work suggests a general approach to EDLC design leading to the maximum energy density, which has been now proved for both solvated organic salts and solvent-free liquid electrolytes.

Item Type:Article
Additional Information:Thanks to American Chemical Society editor. The definitive version is available at http://pubs.acs.org The original PDF of the article can be found at Journal of the American Chemical Society website : http://pubs.acs.org/journal/jacsat
HAL Id:hal-03578188
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Other partners > Drexel University (USA)
Laboratory name:
Deposited On:03 Jun 2009 12:27

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