Thermally stable sulfonated nanoporous aryl epoxy resin as proton exchange membranes at elevated temperatures

This paper proposes a new proton exchange membrane (PEM) based on photochemically synthesized nano porous aryl epoxy resin (npAER) sulfonated by sulfanilic acid. The npAER PEM fabrication process involves solvent-induced nanoporous structure formation combined with photopolymerization for microstructure fabrication. The PEM was placed in the cathode of a half-fuel cell for testing in 0.5M H₂SO₄ at different temperatures with a constant oxygen flow. When compared to commercial PEM based on Nafion^®, this npAER PEM exhibits increased current density from -0.456 (mA/cm²) to -1.14 (mA/cm²) as temperature increased from 60°C to 90°C, while Nafion^® demonstrates current density drop by two orders of magnitude. The new npAER PEM shows decent thermal stability, mechanical strength and proton transport ability at a higher temperature (90°C).