Enhanced stability of pyridine-containing poly(arylene ether) membranes for vanadium redox flow battery: influence of backbone structure

Vanadium redox flow batteries (VRFBs) are emerging as large-scale energy storage devices to solve volatility in the utilization of renewable energy. As key components of VRFBs, membranes still suffer from problems such as high cost, low conductivity, or insufficient stability. Pyridine-containing poly (aryl ether)s have the advantages of low monomer cost, simple synthesis process, and easy processing into membranes. In this work, a series of pyridine-containing poly (aryl ether) (PyPEK, PyPES, and PyPEF) based on different backbones (4,4'-difluorobenzophenone, 4,4'-dichlorodiphenyl sulfone, and perfluorobiphenyl) were synthesized. The effects of the backbones on the membrane swelling behavior, basic membrane properties, battery performance, and stability of the membranes were studied. The PyPEF membrane exhibited excellent battery performance (EE = 93.78% at 80 mAcm -2 , EE = 86.24% at 200 mAcm -2 , and EE = 80.25% at 300 mAcm -2 ) and excellent cycling stability (3000 cycles) in VRFB, which is highly attractive for application in VRFB.