Synthesized Yttria Stabilised Zirconia as filler in Proton Exchange Membranes (PEMs) with enhanced stability

Composite membranes based on Perfluorosulphonic Acid (PSFA) represent a possible solution to operate at temperatures over 100 °C and low relative humidity (RH) levels in Polymer Electrolyte Fuel Cells (PEFCs). Yttria Stabilised Zirconia (YSZ) containing an 8 mol.% of yttrium oxide was synthesised and used to obtain Nafion® membranes with a variable content of YSZ (3, 5, 10 wt%). The membranes were characterised in terms of XRD, Ion Exchange Capacity (IEC), water uptake and swelling at different temperatures (room T, 80 and 95 °C). Proton conductivity, single cell tests in H2/air (I-V curves) and Accelerated Degradation Tests (ADTs) were conducted at 120 °C 75% RH. The composite membrane containing a 5 wt% of synthesized YSZ (NsynYSZ5) had the best performance and the highest electrochemical stability, reaching 48 cycles against to 28 cycles of a pristine Nafion membrane.