A Reinforced Perfluorosulfonic Acid Membrane with PE Mesh

Perfluorosulfonic acid (PFSA) membranes are a key component in many applications, but their low dimensional stability and mechanical strength can result in unsatisfactory device performance and a short life span. To effectively and economically mitigate these limitations with the lowest possible sacrifice of desirable properties, we report herein a PFSA membrane reinforced with a low-cost and easily available polyethylene (PE) mesh fabricated using a simple solution casting method. The high-strength and non-swellable mesh embedded in the PFSA matrix restricts its free swelling. As a result, the reinforced membrane shows a remarkably enhanced dimensional stability, lowering the areal swelling ratio to ~8% in water at 100 °C, in contrast to the ~58% of the unreinforced solution-cast membrane and ~44% of the melt-extruded commercial N117 membrane. Although the non-conductive PE mesh poses certain hindrances to proton transport, the reinforced membranes maintain ~94% of the proton conductivity of the pure PFSA membrane. Moreover, the mechanical strength of the reinforced membrane is enhanced to nearly three times that of the unreinforced one, reaching ~44 MPa. The incorporation of the PE mesh also leads to an enhanced resistance to oxidative corrosion and H₂ gas crossover of the membrane. This research demonstrates a promising technological pathway for developing high-performance and cost-competitive PFSA membranes.