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MM: Fachverband Metall- und Materialphysik

MM 44: Functional Materials II

MM 44.8: Vortrag

Freitag, 18. März 2011, 12:15–12:30, IFW A

Hybrid electrode for electrochemical capacitors consisting of a MnO₂ infiltrated carbon aerogel — •C. Weber¹, V. Lorrmann¹, G. Reichenauer¹, V. Dyakonov^1,2, and J. Pflaum^1,2 — ¹Bavarian Center for Applied Energy Research e.V. (ZAE Bayern), D-97074 Würzburg — ²Julius-Maximilians-University of Würzburg, Institute of Physics, Experimental Physics VI, D-97074 Würzburg

Electrochemical capacitors (EC) bridge the gap between conventional capacitors with high power but low energy density and batteries with high specific energy density but rather low power density. There are two types of EC: Double-layer capacitors, based on the electrostatical storage of charges in the Helmholtz-layer between the electrolyte and the electrode of large surface area, the latter typically consisting of activated carbon. In pseudocapacitance capacitors charging is of faradaic nature, e.g. by redox processes in oxides of transition metals. We have prepared EC hybrid electrodes by infiltrating a carbon aerogel with manganese oxide (MnO₂).

Variations in structure of the carbon aerogel backbone and the amount of deposited MnO₂ were characterized electrochemically and structurally. Due to the MnO₂ deposition, the gravimetric capacitance was augmented by a factor 2, whereas the volumetric capacitance was increased by a factor 5, compared to the capacitance of the bare carbon aerogel, respectively. Remarkably, these findings are independent of the concentration of MnO₂ in the precursor.

Financial support by Deutsche Bundesstiftung Umwelt is gratefully acknowledged.