Enhanced capacitance of nitrogen-doped hierarchically porous carbide-derived carbon in matched ionic liquidsElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ta04773k

• Main Authors: Ewert, J.-K, Weingarth, D, Denner, C, Friedrich, M, Zeiger, M, Schreiber, A, Jäckel, N, Presser, V, Kempe, R
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta04773k

Supercapacitors combine efficient electrical energy storage and performance stability based on fast electrosorption of electrolyte ions at charged interfaces. They are a central element of existing and emerging energy concepts. A better understanding of capacitance enhancement options is essential to exploit the full potential of supercapacitors. Here, we report a novel hierarchically structured N-doped carbon material and a significant capacitance enhancement for a specific ionic liquid. Our studies indicate that matching of the electrode material and the ionic liquid specifically leads to a constant normalized resistance of the electrode material (voltage window up to ±1 V vs. carbon) and a significant enhancement of the specific capacitance. Such effects are not seen for standard organic electrolytes, non-matched ionic liquids, or non-N-doped carbons. A higher N-doping of the electrode material improves the symmetric full cell capacitance of the match and considerably increases its long-term stability at +3 V cell voltage. This novel observance of enhanced specific capacitance for N-doped carbons with matched ionic liquid may enable a new platform for developing supercapacitors with enhanced energy storage capacity. Supercapacitor performance can be significantly increased when matching a suitable ionic liquid to nitrogen-doped nanoporous carbon.