Hydrocarbon-based composite membranes for PEM water electrolysis: From single-cell performance to stack-level operation

Hydrocarbon-based three-layered composite membranes were fabricated for proton exchange membrane water electrolysis (PEMWE) by impregnating polyethylene (PE) and polytetrafluoroethylene (PTFE) substrates with sulfonated poly(arylene thioether sulfone) (SPATS). Compared with the pristine SPATS membrane, the composites showed improved dimensional stability and mechanical properties, approximately 2.5–2.8-fold lower hydrogen permeability, and enhanced hydrothermal stability due to suppressed swelling. In single-cell PEMWE tests, SPATS-PE and SPATS-PTFE achieved 6.60 and 7.79 A cm −2 at 1.9 V, respectively, outperforming the pristine SPATS and Nafion 212 membranes (6.07 and 5.36 A cm −2 , respectively). The composites also exhibited lower degradation rates, with SPATS-PTFE showing only 7.2% molecular weight loss. A three-cell stack using SPATS-PTFE delivered 6.14 A cm −2 at 5.7 V, corresponding to 78.8% of single-cell performance, and operated for 300 h at 2 A cm −2 . These results demonstrate the potential of the composite membrane for stack-level PEMWE applications and suggest that further optimization of cell components is needed to improve long-term durability.