Phosphonate-based iron complex for a cost-effective and long cycling aqueous iron redox flow battery

Autor: Gabriel S. Nambafu, Aaron M. Hollas, Shuyuan Zhang, Peter S. Rice, Daria Boglaienko, John L. Fulton, Miller Li, Qian Huang, Yu Zhu, David M. Reed, Vincent L. Sprenkle, Guosheng Li
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nature Communications, Vol 15, Iss 1, Pp 1-9 (2024)
Druh dokumentu: article
ISSN: 2041-1723
DOI: 10.1038/s41467-024-45862-3
Popis: Abstract A promising metal-organic complex, iron (Fe)-NTMPA2, consisting of Fe(III) chloride and nitrilotri-(methylphosphonic acid) (NTMPA), is designed for use in aqueous iron redox flow batteries. A full-cell testing, where a concentrated Fe-NTMPA2 anolyte (0.67 M) is paired with a Fe-CN catholyte, demonstrates exceptional cycling stability over 1000 charge/discharge cycles, and noteworthy performances, including 96% capacity utilization, a minimal capacity fade rate of 0.0013% per cycle (1.3% over 1,000 cycles), high Coulombic efficiency and energy efficiency near 100% and 87%, respectively, all achieved under a current density of 20 mA·cm-². Furthermore, density functional theory unveils two potential coordination structures for Fe-NTMPA2 complexes, improving the understanding between the ligand coordination environment and electron transfer kinetics. When paired with a high redox potential Fe-Dcbpy/CN catholyte, 2,2′-bipyridine-4,4′-dicarboxylic (Dcbpy) acid and cyanide (CN) ligands, Fe-NTMPA2 demonstrates a notably elevated cell voltage of 1 V, enabling a practical energy density of up to 9 Wh/L.
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