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Improvement of the structural and chemical properties of a commercial activated carbon for its application in electrochemical capacitors
Auteur(s)
Date de parution
2008
In
Electrochimica Acta, Elsevier, 2008/53/5/2210-2216
Résumé
The present paper shows that the performance of an inexpensive activated carbon used in electrochemical capacitors can be significantly enhanced by a simple treatment with KOH at 850 °C. The changes in the specific surface area, as well as in the surface chemistry, lead to high capacitance values, which provide a noticeable energy density. <br> The KOH-treatment of a commercial activated carbon leads to highly pure carbons with effective surface areas in the range of 1300–1500 m<sup>2</sup> g<sup>−1</sup> and gravimetric capacitances as high as three times that of the raw carbon. <br> For re-activated carbons, one obtains at low current density (50 mA g<sup>−1</sup>) values of 200 F g<sup>−1</sup> in aqueous electrolytes (1M H<sub>2</sub>SO<sub>4</sub> and 6M KOH) and around 150 F g<sup>−1</sup> in 1M (C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>NBF<sub>4</sub> in acetonitrile. Furthermore, the resulting carbons present an enhanced and stable performance for high charge/discharge load in organic and aqueous media. <br> This work confirms the possibilities offered by immersion calorimetry on its own for the prediction of the specific capacitance of carbons in (C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>NBF<sub>4</sub>/acetonitrile. On the other hand, it also shows the limitations of this technique to assess, with a good accuracy, the suitability of a carbon to be used as capacitor electrodes operating in aqueous electrolytes (H<sub>2</sub>SO<sub>4</sub> and KOH).
Identifiants
Type de publication
journal article
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