3D-Printed Metal Electrodes with Enhanced Bubble Removal for Efficient Water Electrolysis.

Improving the water electrolysis efficiency at high current densities is constrained by the structure of available foam and mesh electrodes, which suffer from internal bubble entrapment. Herein, we used laser powder bed fusion-based 3D printing to fabricate Schwarz Diamond (SD) structure nickel electrodes for water electrolysis. After loading with NiMoFeO_x as the oxygen evolution reaction catalyst and MoNi₄-MoO₂ as the hydrogen evolution reaction catalyst, the anion exchange membrane water electrolyzer utilizing SD nickel electrodes achieved a current density of 1 A cm^-2 at 1.74 V, outperforming conventional nickel foam and mesh electrode-based electrolyzers in the same conditions and demonstrated durable operation for more than 1000 h. In-situ observations of bubble evolution in the electrolyzer and single-frequency impedance spectra reveal that the 3D-printed SD structure exhibits highly efficient bubble/liquid transport. The present study investigates the potential of 3D printing technology in the fabrication of metallic porous electrodes for efficient water electrolysis.