March 4, 2025
Journal Article

Strategically modified ligand incorporating mixed phosphonate and carboxylate groups to enhance performance in all-iron redox flow batteries

Abstract

Iron redox flow batteries (Fe-RFBs) hold significant promise, potentially replacing vanadium (V) in VRFBs with Fe, for achieving cost-effectiveness and utilizing abundant materials. Here, we present a design of a novel Fe complex utilizing a nitrogenous phosphonate/carboxylate mixed ligand, N,N-Bis(phosphonomethyl)glycine (BMPG), aimed at achieving high performance as an Fe anolyte. Compared to its all-phosphonate form, nitrilotri(methylphosphonic acid) (NTMPA), the new complex Fe(BPMG)2 demonstrates a negatively shifted redox potential, resulting in approximately a 20% increase in battery output voltage. Full battery testing paired with ferrocyanide catholyte demonstrates stable cycling (capacity degradation

Published: March 4, 2025

Citation

Nambafu G.S., A.M. Hollas, P.S. Rice, J.M. Weller, D. Boglaienko, D.M. Reed, and V.L. Sprenkle, et al. 2025. Strategically modified ligand incorporating mixed phosphonate and carboxylate groups to enhance performance in all-iron redox flow batteries. Advanced Energy Materials 15, no. 1:Art. No. 2403149. PNNL-SA-196533. doi:10.1002/aenm.202403149

Research topics

Electrochemical Energy Storage