A highly stable reinforced PEM assisted by resveratrol and polydopamine-treated PTFE

Abstract

The need to reduce the cost of proton exchange membranes (PEMs) leads to less usage of perfluorinated sulfonic acid (PFSA), which would definitely result in a decline in the membrane lifespan under the attack of free radicals. In this study, polytetrafluoroethylene (PTFE) is used as a reinforced material to make a thinner composite membrane due to the poor mechanical strength of the pristine membrane. Moreover, a polydopamine (PD)-treated strategy was selected to make hydrophilic PTFE, which allows the adoption of a high-boiling point solvent for the dissolution of resveratrol, a natural antioxidant produced by plants that acts as a free radical scavenger (FRS) in the membrane to prevent the membrane from being attacked. With the help of dimethyl formamide (DMF), a high-boiling point solvent, and hydrophilic groups in PD molecules, a Nafion/PD@PTFE/resveratrol composite membrane with a thickness of 10 μm was prepared and tested using an accelerated degradation test (ADT) strategy. With a resveratrol dose of 1 wt%, the cell presented a lower hydrogen crossover of 2.82 mA cm−2 and a longer lifespan than those of a membrane without resveratrol while cell performance did not suffer too much damage. In the ADT experiment, the hydrogen crossover of Nafion/PD@PTFE/resveratrol was still less than 20 mA cm−2 after 8 open circuit voltage (OCV) cycles, while that without resveratrol increased to 80 mA cm−2 in 3 OCV cycles.