Amade Rovira, RogerMuyshegyan-Avetisyan, ArevikMartí González, JoanPérez del Pino, ÁngelGyörgy, EnikoPascual Miralles, EstherAndújar Bella, José LuisBertrán Serra, Enric2020-05-042020-05-042019-02-041996-1944https://hdl.handle.net/2445/158581Graphene nano-walls (GNWs) are promising materials that can be used as an electrode in electrochemical devices. We have grown GNWs by inductively-coupled plasma-enhanced chemical vapor deposition on stainless steel (AISI304) substrate. In order to enhance the super-capacitive properties of the electrodes, we have deposited a thin layer of MnO2 by electrodeposition method. We studied the effect of annealing temperature on the electrochemical properties of the samples between 70 °C and 600 °C. Best performance for supercapacitor applications was obtained after annealing at 70 °C with a specific capacitance of 104 F·g−1 at 150 mV·s−1 and a cycling stability of more than 14k cycles with excellent coulombic efficiency and 73% capacitance retention. Electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge measurements reveal fast proton diffusion (1.3 × 10−13 cm2·s−1) and surface redox reaction after annealing at 70 °C.13 p.application/pdfengcc-by (c) Amade Rovira, Roger et al., 2019http://creativecommons.org/licenses/by/3.0/esGrafèAparells electrònicsAcer inoxidableGrapheneElectronic apparatus and appliancesStainless steelinfo:eu-repo/semantics/article6856022020-05-04info:eu-repo/semantics/openAccess30720766