Highly stable pyridinium-functionalized cross-linked anion exchange membranes for all vanadium redox flow batteries

Pyridinium-functionalized cross-linked anion exchange membranes are fabricated to address the issue of low chemical stability for vanadium redox flow batteries. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) (BrPPO/Py) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. A cycling test shows that the VRFBs assembled with BrPPO/Py enable to maintain 80% of the specific discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle−1 at a current density of 200 mA cm−2.282