High-performance Porous 3D Ni Skeleton Electrodes for the Oxygen Evolution Reaction in AEMWEs

Abstract

A key component of green hydrogen production technologies is the fabrication of large-scale electrodes for use in anion electrolyte membrane water electrolysers (AEMWEs). One strategy to achieve that goal is to manufacture Ni-based 3D electrode skeletons that can be further catalyzed to achieve high current densities at low overpotentials. In the present work, shock-wave induced spray (SWIS) and cold spray (CS) deposition techniques were used to prepare 20 cm² Ni-based electrode skeletons. As-deposited SWIS-sprayed Ni skeleton electrodes had 28% porosity. A further increase in porosity up to 43% was achieved by CS deposition of Ni-Al spheroidal powder made of an aluminum core encapsulated in a nickel shell, with subsequent leaching of Al. The resulting electrode showed good structural and mechanical integrity. For the more porous CS skeleton electrodes, the electrochemically active surface area was increased by a factor of 2100 compared to the bulk Ni plate. The overpotential at 10 mA cm^-2 of the more active leached CS-deposited skeleton electrode was 250 mV, compared to 296 for a commercially Ni foam with 90% porosity and 365 mV for a Ni plate electrode. These coatings are an effective methodology for the preparation of 3D Ni skeleton electrodes.