Synergistic integration of sulfonated aromatic polymer blends for enhanced performance in proton exchange membrane fuel cells

This research advances the development of proton exchange membrane fuel cells (PEMFCs) systems. Here report blending sulfonated poly (1,4 phenylene ether-ether sulfone) (SPEES) with sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) (SPPO) to enhance the physicochemical stability and long-term durability of the resulting proton exchange membranes. The blended membranes are fabricated through sulfonation reactions and solvent-casting techniques. Acidic group pairing occurs between the sulfonic acid groups (-SO₃H) of both polymer backbones, which enhances the mechanical strength, oxidative stability, proton transfer, and performance of the PEMFCs. Notably, the 25 wt% of SPPO concentration on the SPEES polymer matrix achieves a maximum proton conductivity of 110.93 mS cm⁻¹ compared to other membranes at 80 °C and 100% relative humidity (RH). Furthermore, the single-cell performance of the SPEES/SPPO (25 wt%) blended membrane achieves the maximum power density of 347.24 mW cm⁻² and a current density of 956.52 mA cm⁻² at 60 °C and 100% RH, with an open-circuit voltage decay of 0.23 mV h⁻¹ during 104 h of continuous operation. These results show that the incorporation of SPPO significantly enhances the overall performance of the SPEES polymer, improving its suitability for use in PEMFCs.