Degradation\nof a\nBipolar Membrane in a Hybrid Acid/Alkali\nElectrolyzer Studied by X‑ray Computed Tomography

The\nuse of a bipolar membrane (BPM) in a hybrid acid/alkali\nelectrolyzer\nis widely considered as a promising energy technology for efficient\nhydrogen production. The stability of a BPM is often believed to be\nlargely limited by the anion exchange layer (AEL) due to the hydrophilic\nattack of AEL polymers by hydroxide groups in alkaline. In this study,\nwe employ X-ray computed tomography (CT) to investigate the degradation\nbehaviors of BPM and found that the cation exchange layer (CEL) experiences\nmore pronounced degradation compared with the AEL during water splitting\noperations. Despite its chemical stability in both acidic and alkaline\nenvironments, the CEL is more prone to electrochemical corrosion under\nthe influence of applied voltages. This susceptibility leads to the\nformation of micropores and a consequent increase in the porosity.\nThe results of this work provide a new perspective on and highlight\nthe complexity of the degradation behaviors of BPMs in hybrid acid/alkali\nelectrolyzers.