Design and optimisation of a reference electrode integrated anion exchange membrane water electrolyser for hydrogen production

Zero-gap water electrolysers have shown their potential in large scale green hydrogen production, but their cost effectiveness and long-term durability remain limited by an incomplete understanding of electrocatalysts and electrode materials behaviour during full-cell electrolysis. Here, a gasket-free anion exchange membrane water electrolyser (AEMWE) has been designed with an integrated reference electrode (RE) next to the membrane electrode assembly (MEA). A zero-gap design between the electrode and the membrane is achieved without the limitations of a gasket, ensuring close contact and minimising the system resistance and allowing precise monitoring of anode and cathode potentials individually during electrolysis. With NiFe(OH) 2 as the anode catalyst and Ni x S y as the cathode catalyst, electrolysis at a current density of 500 mA cm −2 was achieved at 1.86 V cell voltage with 1 M KOH electrolyte at 333 K. Electrochemical impedance spectroscopy (EIS) measurement with a Hg/HgO reference electrode during the electrolysis at the same conditions further reveal the potential loss distribution: 0.10 V from IR drop, 0.35 V from anode and 0.27 V from cathode. These results demonstrate a simple but useful platform for decoupling performance-limiting processes in AEMWE systems and guiding the design of more durable and efficient electrolysers.