Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.9: Poster

Montag, 23. März 2009, 14:30–17:00, P2

Composite electrode of carbon aerogel and MnO₂ for electrochemical capacitors — •Christian Weber¹, Volker Lorrmann¹, Carsten Deibel², Jens Pflaum^1,2, Gudrun Reichenauer¹, and Vladimir Dyakonov^1,2 — ¹Bavarian Centre 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 supercapacitors, that store charges electrostatically in the electrochemical double-layer between electrolyte and high surface area electrodes of activated hard carbon. In pseudocapacitance supercapacitors the charge storage is of faradaic nature, e.g. redox processes in MnO₂. We have blended the organic precursor of a synthetic activated hard carbon (carbon aerogel) with MnO₂ particles to be used as electrode for EC. The aim is to combine the faradaic- and the double-layer capacitance of MnO₂ and carbon, to increase the achievable capacity of the electrode. The electrochemical properties of these composites were investigated with cycling voltammetry, charge/discharge cycling and impedance spectroscopy. Structural analysis was performed via nitrogen sorption, scanning electron microscopy and X-ray diffraction.