The perflourosulphonic acid (PFSA) membranes find applications in liquid and gas separations, electrochemical and electro-organic syntheses and clean fuel and energy productions (i.e., water electrolysis and fuel cell). Protons migrate in PFSA as hydronium ions along the hydrated channels surrounding the sulpho-nated side chains of the perfluorinated polymer backbone. Water management is critical as a decrease in hydration results in a sharp decline in proton conductivity, whereas excessive water leads to electrode flooding that hinders reactant diffusion. Nano-, micro- and macro-composite membranes with dispersed inorganic or inorganic-organic particles dispersed in the PFSA membrane have been extensively studied by various authors. This work investigates the confinement of PFSA and the use of water-retaining zeolites to control the hydration of the proton-conducting membranes at elevated temperatures. PFSA is confined in subnanoliter volumes within porated stainless steel coated with water retaining zeolites. The confinement volumes and zeolites (i.e., ZSM-5, NaX, NaY and HBeta) of different water capacities were examined and mechanistic study were carried out using different spectroscopic techniques. PEMFCs using the new membrane performed better than the standard Nafion MEA, and were capable of operating at high temperatures (i.e., up 160 �C) without the need for humidification.

Effects of confinement on the properties of confined PFSA-zeolite proton-conducting membranes

246th National Meeting (2013)

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