Dresden 2017 – wissenschaftliches Programm
CPP 39.5: Vortrag
Mittwoch, 22. März 2017, 15:45–16:00, POT 81
Three-dimensional graphene-based electrodes for asymmetric supercapacitors — •Maximilian von Seckendorff1, Simon Drieschner1, Jörg Wohlketzetter1, Jose A. Garrido2, and Martin Stutzmann1 — 1Walter Schottky Institut und Physik-Department, Technische Universität München, Garching, Germany — 2The Barcelona Institute of Science and Technology, Bellaterra, Spain
Three-dimensional (3D) graphene-based structures combine the outstanding physical and chemical properties of graphene such as high conductivity, mechanical stability and chemical inertness with a high surface-to-volume ratio, making them highly promising for energy storage applications in supercapacitors. Here we demonstrate the fabrication of 3D graphene-based electrodes by chemical vapor deposition using sintered copper particles and electrodeposited nickel/copper alloys as catalytic metal substrates. After selective wet chemical etching of the metal scaffold, a freestanding graphene foam of high structural quality as confirmed by Raman spectroscopy is obtained. In an asymmetric supercapacitor, this graphene foam is used as the cathode and is combined with a graphene foam coated with pseudocapacitive elements such as manganese dioxide as the anode. This combination results in an extended electrochemical potential window above 1.5 V and, therefore, a higher energy density (> 5 Wh/kg) compared to symmetric supercapacitors. The electrochemical performance of this asymmetric capacitor is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and charge-discharge-measurements and confirms its great potential for energy storage applications.