Lifetime Prediction Approach Applied to the Aquivion T Short Side Chain Perfluorosulfonic Acid Ionomer Membrane for Intermediate Temperature Proton Exchange Membrane Fuel Cell Application

Degradation and durability studies of the short side chain perfluorosulfonic acid ionomer membrane, Aquivion, of Solvay Specialty Polymers, are described in a fuel cell operation beyond 100 degrees C. Specific electrochemical accelerated stress tests under a dynamic electric load cycling profile were developed to submit the membrane to hydration-dehydration cycles, while the effect of operation temperature was also investigated to reproduce typical power demands and/or thermal gradient periods likely to be encountered during seasonal variation of a micro-combined heat and power system. Aquivion is a high performance membrane which is shown in this study to sustain operation until 110 degrees C, higher than was possible with Nafion (R) under similar conditions. Post-test observations studies by electron microscopy and ex situ tensile measurements bring to light modifications of membrane thickness and mechanical properties that rationalize an upper operating temperature of 120 degrees C. Membrane thermal annealing is shown to increase lifetime with the ageing procedures used. A predictive lifetime model is proposed by correlating the estimated lifetime values and the experimental data via a lifetime coefficient.