Influence of Supporting Electrolyte on Hydroxide Exchange Membrane Water Electrolysis Performance: Anolyte

Hydroxide-exchange-membrane water electrolysis (HEMWE) is an emerging hydrogen-production pathway that combines many advantages of incumbent alkaline (AWE) and proton-exchange-membrane (PEMWE). Advancement in HEMWE has been accelerated with the development stable conductive hydroxide exchange membranes (HEMs) a more comprehensive understanding gas-evolving kinetics. However, performance durability without supporting electrolytes (SELs) remain inferior to PEMWE AWE little known about role impact SELs. This study investigates effects SELs used as anolyte solutions HEMWEs including cation-type, anion-type, SEL conductivity pH, presence carbonates increased cation/OH ? ratios on cell voltage stability. We report our findings (i) potential high-frequency resistance did not correlate conductivity, (ii) cation-type influences at low current densities (<50 mA cm ?2 ) predicted by half-cell measurements, (iii) ratio causes overpotentials, (iv) are exchanged HEM but removed via self-purging high density. Overall, this concludes concentrated KOH still best SEL.