High-performance SO₂-depolarized electrolysis cell using advanced polymer electrolyte membranes

Three different proton conducting polymeric membrane materials (Nafion® 115, Nafion® 212, and sulfonated Diels-Alder polyphenylene [SDAPP]) were evaluated for use in SO 2 -depolarized electrolyzers the production of hydrogen via hybrid sulfur cycle. Their performance was measured using water feed strategies to minimize overpotential losses while maintaining high product acid concentration. Both thin membranes 212 SDAPP) showed superior that thicker 115. The SDAPP electrode assembly (MEA) performed well at higher concentrations, low ohmic kinetic overpotentials. Finally, short-term (100-h) stability tests under constant current conditions minimal degradation MEAs. MEA approached targets needed make cycle a competitive process (product concentration ≥65 wt% H 4 ≤ 0.6-V cell potential ≥0.5 A-cm −2 density). • High transport across allows efficient electrolysis. Thicker can only operate well-hydrated environments. Thin with wet cathode dry anode. (>60 wt%) produced potentials <1 V. Stable operation observed moderate operating conditions.