Polymers platinum-polyphosphazenes

There is only one example in the literature of polyphosphazene performance in a proton-exchange membrane (PEM) hydrogen fuel ceU. Allcock and Lvov [45] tested a sulfonimide polyphosphazene membrane in a hy-drogen/oxygen fuel cell at room temperature and at 80 °C. The membrane-electrode-assembly (MEA) was fabricated from a 100 xm thick sulfonimide polyphosphazene membrane that was crosslinked with y-radiation (40 MRad). The polymer lEC was 0.99 mmol/g, with an equilibrium water swelling of 42%, and a proton conductivity of 0.058 S/cm. The anode and cathode were prepared from carbon-supported platinum (20% Pt on Vulcan XC-72R) at a Pt loading of 0.33 mg/cm. The electrodes were hot pressed onto the membrane at 65 °C and 400 psi for 30 s. As a reference, a Nafion 117 MEA was also prepared with the same electrode catalyst at a loading of 0.26 mg/cm for the anode and 0.48 mg/cm for the cathode. For Nafion, the electrodes were hot pressed at 125 °C and 1400 psi for 2 min. 

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