High‐Rate Alkaline Water Electrolysis at Industrially Relevant Conditions Enabled by Superaerophobic Electrode Assembly

Abstract

Alkaline water electrolysis (AWE) is among the most developed technologiesfor green hydrogen generation. Despite the tremendous achievements in boosting the catalytic activity of the electrode, the operating current density of modern water electrolyzers is yet much lower than the emerging approaches such as the proton-exchange membrane water electrolysis (PEMWE). One of the dominant hindering factors is the high overpotentials induced by the gas bubbles. Herein, the bubble dynamics via creating the superaerophobic electrode assembly is optimized. The patterned Co-Ni phosphide/spinel oxide heterostructure shows complete wetting of water droplet with fast spreading time (≈300 ms) whereas complete underwater bubble repelling with 180°c ontact angle is achieved. Besides, the current collector/electrode interface is also modified by coating with aerophobic hydroxide on Ti current collector. Thus, in the zero-gap water electrolyzer test, a current density of 3.5 A cm −2 is obtained at 2.25 V and 85 °C in 6 m KOH, which is comparable with the state-of-the-art PEMWE using Pt-group metal catalyst. No major performance degradation or materials deterioration is observed after 330 h test. This approach reveals the importance of bubble management in modern AWE, offering a promising solution toward high-rate water electrolysis.

Suppressing carbon corrosion via mechanically mixing transition metal phosphide clusters: a comparative in situ study in alkaline media

“…S2 †). FeP-CoP was selected as the constituent since it demonstrated excellent OER activity as documented in our previous work, 25,26 and we envisage that the phosphide domains might enable the transfer of oxidation sites at high anodic potentials from carbon to the phosphide surface. The mechanical mixing of phosphide and carbon minimized the length of the interface where the catalytic oxidation of carbon might proceed.…”

Rational Design of Hydrogen Evolution Reaction Electrocatalysts for Commercial Alkaline Water Electrolysis

“…[60] Although this approach can address the effects of bubble retention to some extent, bubbles can still generate a "gas blanket" between the electrode and the diaphragm and may cause complicated local convection of the electrolyte, which causes additional overpotential losses. [61][62][63] Shen et al used a 3D computational fluid dynamics model to study the transient bubble behavior in a commercial AWE. They found that bubbles would form bubble plugs within the flow channel, which had a significant negative impact on the electrolyzer's performance.…”

Understanding the Effect of Triazole on Crosslinked PPO–SEBS-Based Anion Exchange Membranes for Water Electrolysis

“…Alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), and anion exchange membrane water electrolysis (AEMWE) are the three types of WE procedures based on the electrolyte employed [ 10 , 11 , 12 ]. AWE is a technique that uses alkaline solutions as electrolytes to electrolyze water to produce hydrogen and oxygen.…”