Enhanced surface hydrophobisation for improved performance of carbon aerogel electrochemical capacitor

A more efficient surfactant vinyl trimethoxysilane (vtmos) than previously reported one, sodium oleate (OAS), has been employed to enhance surface hydrophobisation of carbon aerogel for electric double layer capacitor (EDLC) application. In comparison with attachment of hydrophobic moiety of OAS species to carbon surface grafting of vinyltrimethoxysilane functional group enhances more efficiently the hydrophobisation of carbon material and the affinity toward propylene carbonate (PC) solvent, and accordingly improves more considerably the wettability of carbon in PC-based electrolyte solution. The enhanced wettability facilitates more rapid electrolyte ions transport within micropores of the vtmos modified carbon aerogel, resulting in lower internal resistance and energy loss than OAS modified carbon capacitor, and also favors more surface area for EDL formation, resulting in higher specific capacitance and energy for vtmos modified carbon aerogel electrochemical capacitor. In addition, vtmos modified carbon material has shown comparable charge-discharge cycling stability to that obtained by the original carbon. (c) 2007 Elsevier Ltd. All rights reserved.