Simple process to nanostructured Raney-nickel electrodes for highly active and cost-efficient hydrogen evolution in alkaline water electrolysis (AWE)
Timon E. Günther, Jonas Schick, T. W. Körner, Tobias Mangold, Richard Weihrich
Abstract
In this work we present a nanostructured nickel-based electrode with high surface area as cathode for the hydrogen evolution (HER) during alkaline water electrolysis (AEL). The electrodes are prepared via mechanical plating of aluminum on a nickel sheet and thermal treatment in N 2 -atmosphere at different temperatures to achieve leachable NiAl-phases such as Ni 2 Al 3 and NiAl 3 . Focus is to increase the electrochemical surface area (ECSA) significantly. The electrochemical performance is evaluated with cyclic voltammetry (CV) and chronopotentiometry (CP) in a three-electrode and full cell setup at current densities up to 1 A/cm 2 . High efficiency values at the cathode with Tafel slopes from 70 to 80 mV/dec and low overpotentials of 170–200 mV at high currents are determined. Electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP) are used to study resistances, degradation and stability of the fabricated electrodes. The “carpet-like” structure of the electrode leads to a 4200x increased surface area of the Nickel catalyst with optimized gas desorption and transport of hydrogen. • Alkaline water electrolysis (AEL/AWE). • Hydrogen evolution reaction (HER). • Surface engineering to increase the ECSA of Nickel electrodes. • Electrochemical performance evaluation of Ni-based electrodes.