Development of porous nickel-coated stainless steel mesh electrodes for zero-gap electrolyzers: experimental and multiphysics modeling study

Abstract

The decarbonization of industry has positioned green hydrogen as a strategic energy carrier, but the high cost of electrolysis components represents a barrier. To address the high cost of pure Ni catalysts we prepare a porous nickel coating on low-cost stainless-steel mesh (SSM, AISI 316 L) using a scalable two-step electrodeposition–dealloying route with an intermediate Ni-Watts layer to enhance adhesion (denoted as SSM/Ni/Niporous). The coatings exhibit coral-like nanostructures with pore sizes of ∼100–300 nm, yielding a large electrochemically active surface area (ECSA ≈ 54 cm2 per 1 cm2 projected area). This enhances the hydrogen evolution reaction (HER) kinetics in a 1.0 M KOH (j0 ≈ 2.95 × 10–1 mA cm–2, Tafel slope ≈ 68 mV dec‑1). Moreover, the optimized catalyst was tested in a zero-gap cell, showing good activity (SSM/Ni/Niporous deliver ≈523 mA cm–2 at 2.0 V) and sustaining stable performance over 24 h at 100 mA cm–2. To complement our study, a multiphysics model was performed, and the obtained results reproduced polarization behavior with deviations below ∼5%, confirming that performance gains stem from increased ECSA and improved HER kinetics.