Nano-crystalline Yttria-Stabilised Zirconia as filler for Proton Exchange Membranes (PEM) in fuel cells

Yttria-stabilized zirconia (YSZ) nanometric oxide has been extensively studied as an inorganic additive to be used in composite polymer membranes for Polymer Electrolyte Fuel Cells (PEFC) fed by H2/air. Nano-crystalline Yttria-Stabilised-Zirconia (YSZ) powders synthesised varying the yittria concentration (4,8 - 15 mol.%) have been prepared and characterized to verify the doping influence on filler. Composite mmebranes containing a previously used YSZ loading (5wt.%) wre prepared in order to investigate the filler influence on membranes characteristics. Such membranes were characterised in terms of IEC, water retention capacity and swelling at different temperatures The membranes have been actually under study, but the preliminary results demonstrated the good mechanical properties of the membranes. Moreover, the increase of yttria percentage produced an IEC increase exceeding the theoretical value at high percentages (YSZ15). Such behaviour indicates an enhancement of acidic properties that could help the proton conductivity of the membranes. It seems that the filler introduction preserves the hydrophilic and swelling properties of the membranes and it has a positive effect on exchangeable protons. Future work foresees a deep study on proton conductivity, single FC electrochemical performance and degradation of the membranes.