A novel multi-channel porous structure facilitating mass transport towards highly efficient alkaline water electrolysis

Abstract

An advantageous porous architecture of electrodes is pivotal in significantly enhancing alkaline water electrolysis (AWE) efficiency by optimizing the mass transport mechanisms. This effect becomes even more pronounced when aiming to achieve elevated current densities. Herein, we employed a rapid and scalable laser texturing process to craft novel multi-channel porous electrodes. Particularly, the obtained electrodes exhibit the lowest Tafel slope of 79 mV dec−1 (HER) and 49 mV dec−1 (OER). As anticipated, the alkaline electrolyzer (AEL) cell incorporating multi-channel porous electrodes (NP-LT30) exhibited a remarkable improvement in cell efficiency, with voltage drops (from 2.28 to 1.97 V) exceeding 300 mV under 1 A cm−1, compared to conventional perforated Ni plate electrodes. This enhancement mainly stemmed from the employed multi-channel porous structure, facilitating mass transport and bubble dynamics through an innovative convection mode, surpassing the traditional convection mode. Furthermore, the NP-LT30-based AEL cell demonstrated exceptional durability for 300 h under 1.0 A cm−2. This study underscores the capability of the novel multi-channel porous electrodes to expedite mass transport in practical AWE applications.