SPPSU-based hybrid proton conducting polymeric electrolytes for intermediate temperature PEMFCs

Polyphenylsulfone (PPSU) was reacted with SiCl4 to afford silylated telechelic polymers having different inorganic content, which were sulfonated to different degrees (0.05 ≤ DS ≤ 2) using H2SO4 or ClSO3Si(CH3)3. A class II organic-inorganic hybrid polymer was then synthesized via cross-linking through Si-O-Si bonds generated by non-hydrolytic sol-gel reactions. The physicochemical properties of the hybrid were suitable for the preparation of self-standing, flexible and homogeneous membranes which were characterized ATR/FTIR spectroscopy demonstrating the formation of covalent bonds between the organic and inorganic components and the absence of dispersed inorganic silicon. The electrochemical performance was analyzed by electrochemical impedance spectroscopy which showed adequately high conductivity values to make the hybrid polymer a suitable candidate for application as electrolyte in PEMFCs operating at T > 100 °C.