Polysulfone-Based Membranes Modified with Ionic Liquids and Silica for Potential Fuel Cell Applications

The urgent need for sustainable, low-emission energy solutions has positioned proton exchange membrane fuel cells (PEMFCs) as a promising technology in clean energy conversion. Polysulfone (PSF) membranes with incorporated ionic liquid (IL) and hydrophobic polydimethylsiloxane-functionalized silica (SiO₂-PDMS) were developed and characterized for their potential application in PEMFCs. Using a phase inversion method, membranes with various combinations of PSFs, SiO₂-PDMS, and 1-butyl-3-methylimidazolium triflate (BMI.TfO) (1-10 wt%) were prepared and characterized to assess their morphology, porosity, wettability, ionic conductivity, and thermal stability. Incorporating IL significantly altered the membrane structure, increasing porosity and surface roughness, while SiO₂-PDMS enhanced IL retention, reducing leakage by up to 32%. Proton conductivity increased by up to 30 times compared to pure PSF, and membranes exhibited high hydrophilicity at optimal IL concentrations. This work highlights the potential of IL and silica-based membranes for practical applications in PEMFCs.