Durability improvement for ePTFE reinforced perfluorosulfonic acid membranes by natural organic free radical scavengers

Enhancing the chemical durability of perfluorosulfonic acid (PFSA) membranes is important in developing proton exchange membrane fuel cells (PEMFCs). In this paper, a novel expanded polytetrafluoroethylene (ePTFE) reinforced PFSA membrane with nature organic naringin (NAR) as radical scavenger (PFSA@ePTFE/NAR) was prepared by a simple solution-cast method. NAR exhibited an excellent radical scavenging ability and does not influence the original PFSA structure. A comparison between NAR and Ce3+ showed that NAR had higher free radical scavenging ability. PFSA@ePTFE/NAR shows high proton conductivity of 153.1 mS cm−1 in water at 80 °C, high tensile strength of 50.5 MPa, and good output single cell performance. The addition of 1 wt% NAR significantly reduced the fluoride ion release rate of the membrane by 81% after the 96 h Fenton's test, and prolonged the lifetime of the membrane in cell as demonstrated by single-cell tests and open-circuit voltage tests.