Reinforced short-side-chain Aquivion® membrane for proton exchange membrane water electrolysis

A reinforced short-side-chain perfluorosulfonic acid (PFSA) Aquivion® membrane with equivalent weight (EW) of 980 g/eq and 50 μm thickness produced by Solvay Specialty Polymers was investigated for operation in polymer electrolyte membrane (PEM) water electrolysis. The membrane produced by a dispersion casting process was reinforced by introducing polytetrafluoroethylene (PTFE) fibres in order to enhance mechanical and dimensional stability properties while keeping high conductivity and decreased ohmic drop for operation at high current density. A conventional extruded PFSA Aquivion® membrane with similar EW and thickness was investigated for comparison under similar operating conditions. Membrane-electrode assemblies (MEAs) made of reinforced membranes were tested in a single cell and compared to extruded membranes bared MEAs. All MEAs consisted of home-made unsupported IrRuOx anode and carbon-supported Pt (40%) cathode electrocatalysts. Electrochemical tests showed better water splitting performance for the reinforced Aquivion® based membrane-electrode assembly as compared to the benchmark based MEA. At 90 °C, a current density of 5 Acm−2 was recorded at 1.8 V (∼80% voltage efficiency vs. Higher Heating Value (HHV) with the reinforced Aquivion® membrane. The cell voltage for the reinforced membrane-based cell was about 50 mV lower than the extruded one during a 3500 h durability test. Moreover, lower recoverable losses were observed for the reinforced membrane based MEA during steady-state durability tests and no membrane thinning appeared after prolonged operation.