Synergetic proton-conducting effect of sulfonated PEEK-MO2-CNT membranes for PEMFC applications

Sulfonated poly(ether ether ketone) − MO 2 (M = Zr, Si) − carbon nanotube nanofiller-enhanced composite membrane in the proton exchange membrane fuel cell is fabricated to enhance the proton mobility and water maintenance at elevated temperature (100 °C). It is observed that the synergic effect of SiO 2 @CNT and ZrO 2 @CNT as nanofiller dramatically enhanced the proton conductivity, thermal stability, chemical reliability, and mechanical strength of the proton exchange membranes. This study shows that between 40 and 60 °C, vehicular mechanism plays key a role, and between 80 and 100 °C, Grotthuss mechanism plays vital role in proton migration. Moreover, the combined proton transfer effect is observed in case of SPEEK/SiO 2 @CNT/ZrO 2 @CNT membrane, which exhibits 2 times better conductivity at 40 and 60 °C, 5 times better at 80 °C, and 8 times better at 100 °C in comparison with the commercial Nafion 212 membrane, under the same setup and conditions. Graphical abstract