Highly Stable Porous Nickel–Iron (Oxy)Hydroxide Layer Electrodeposited on Nickel Foam as Anodes for an Anion Exchange Membrane Water Electrolyzer

Abstract

The development of high-performance and durable electrodes using anion-exchange membrane water electrolyzers (AEMWEs) is essential for sustainable and highly efficient hydrogen production. In this study, we developed a three-dimensional (3D) porous nickel–iron oxyhydroxide (NiFeOOH) anode for an AEMWE. The porous NiFeOOH layer was directly fabricated onto Ni foam by a one-step electrodeposition process with a pulse current (PC) application without the presence of a nonelectrically conductive ionomer. In addition, the effect of the PC electrodeposited anode on the AEMWE performance and durability was investigated by comparing other anodes (the electrodeposited anode using the direct current (DC) process and the conventional anode using the spraying method). This ionomer-free and porous anode showed a higher performance in reducing the Ohmic resistance than the electrodeposited anode with DC as the sprayed anode. The 3D porous structure enhanced the specific surface area and decreased the mass transport resistance. With those beneficial composition and structure, the AEMWE revealed superior performance, which showed 3.87 A cm^–2 at 1.9 V and a small increased overpotential (11.1 mV h^–1), compared to other anodes reported to date. 3D p-NiFe@NF was directly employed as a porous transport layer and catalyst layer with superior AEMWE performance and durability.