Synergistic effects of sulfonated poly(arylene ether sulfone) and sulfonated poly(1, 4-phenylene ether ether sulfone) blends for high-performance proton exchange membrane fuel cells

Developing proton exchange membranes (PEMs) for elevated temperature operations remains a key challenge for next-generation fuel cells. Here, we report an acid-functionalized polymer blend that enhances the overall performance of fuel cell systems by blending a newly synthesized sulfonated aromatic polymer electrolyte. The prepared sulfonated poly(1, 4-phenylene ether ether sulfone) (SPEES) and sulfonated amino fluoro poly(arylene ether sulfone) (SAFPAES) blends enable the formation of continuous proton-transport with increasing thermo-mechanical stability. The structural, thermo-mechanical, and electrochemical studies confirm the increased ionic conductivity and fuel cell performances for the sulfonated polymer blends. Particularly, SPEES/SAFPAES (15 wt%) achieved proton conductivity of 131.4 mS cm −1 at 90 °C in 100% relative humidity. Furthermore, the power and current density of the SPEES/SAFPAES (15 wt%) blend were 1.8 times higher than that of pure SPEES and exhibited a long-term durable performance of over 126 h. These results highlight the side-chain functionalized SAFPAES design-and-blending approach to overcome limitations of conventional backbone sulfonation and indicate that the performance enhancement of the developed polymer electrolyte membrane makes it a promising candidate for high-efficiency PEM fuel cell operation.