Unrevealing the interaction between electrode degradation and bubble behaviors in an anion exchange membrane water electrolyzer

Abstract

Stainless steel felt has been employed in AEMWE as a combination of oxygen evolution reaction (OER) electrocatalysts and porous transport layers, which are not only easy to prepare but also have excellent OER activity under alkaline conditions. However, by realizing detailed electrochemical analysis and multi-scale visualization of the bubble behaviors, it is found that the combined effect of chemical and electrochemical corrosion led to the constant accumulation of metal oxides on the stainless steel fiber surface post-durability compared to the slow-growing hydroxides after initial activation. Moreover, the rougher fiber surface morphology and weaken hydrophilicity cause the adjacent bubbles are slower to detach from the electrode and are more likely to fusion. The measured diameter of bubbles leaving the electrode almost doubles, while the total number of bubbles decreases by about two-thirds, causing the increase of plug flow in the flow field and deteriorating the performance and long-term stability of AEMWE.