Highly ion-selective robust membranes are developed from a series of amidoxime-functionalized Polymers of Intrinsic Microporosity (AO-PIMs), which enable long lifetime operation of aqueous redox flow batteries (RFBs) using low-cost organic redox molecules at benign near-neutral pH, offering cost-effective electricity storage for grid-scale renewable power sources.
Redox flow batteries (RFBs) based on aqueous organic electrolytes are a promising technology for safe and cost-effective large-scale electrical energy storage. Membrane separators are a key component in RFBs, allowing fast conduction of charge-carrier ions but minimizing the cross-over of redox-active species. Here, we report the molecular engineering of amidoxime-functionalized Polymers of Intrinsic Microporosity (AO-PIMs) by tuning their polymer chain topology and pore architecture to optimize membrane ion transport functions. AO-PIM membranes are integrated with three emerging aqueous organic flow battery chemistries, and the synergetic integration of ion-selective membranes with molecular engineered organic molecules in neutral-pH electrolytes leads to significantly enhanced cycling stability.Zum Volltext