A Highly Stable, Capacity Dense Carboxylate Viologen Anolyte towards Long-Duration Energy Storage.

Aqueous organic redox flow batteries (AORFBs) have received increasing attention as an emergent battery technology for grid-scale renewable energy storage. However, physicochemical properties of redox-active organic electrolytes remain fine refinement to maximize their performance in RFBs. Herein, we report a carboxylate functionalized viologen derivative, N,N'-dibutyrate-4,4'-bipyridinium, (CBu) V, as a highly stable, high capacity anolyte material under near pH neutral conditions.