A novel imogolite-reinforced sulfonated polyphenylsulfone as proton exchange membrane in fuel cell applications

The high ion exchange capacity of sulfonated polyphenylsulfone (SPPSU) consists of nanotubular inorganic clay that was developed as a proton exchange membrane for fuel cell application. The nanotubular imogolite (Im) was incorporated into SPPSU polymer matrix under various loading (0.5 wt%, 1 wt%, and 2 wt%) and subjected to thermal annealing up to 180 ºC. Upon heat treating at 180 ºC, SPPSU-Im nanocomposite membranes showing homogenous membrane structure and improved water uptake at higher water temperature compare to pristine SPPSU membrane. The strength of the nanocomposite membrane is decreasing upon the incorporation of the imogolite fillers. Hence, at lower relative humidity conditions, the SPPSU-Im nanocomposite membrane resulting in six times higher proton conductivity than the SPPSU membrane. Furthermore, at 80 °C under fully hydrated conditions, 1 wt% of Im incorporate into the SPPSU matrix can achieve the maximum power density up to 89.8 mW/cm2, which is about 16% higher than the maximum power density produce by SPPSU membrane in single-cell proton exchange membrane fuel cell (PEMFC) system. The results indicating that the imogolite reinforced SPPSU polymer matrix shows significant improvements on the SPPSU polymer matrix as PEM in fuel cell applications.