Nambafu Gabriel S, Hollas Aaron M, Zhang Shuyuan, Rice Peter S, Boglaienko Daria, Fulton John L, Li Miller, Huang Qian, Zhu Yu, Reed David M, Sprenkle Vincent L, Li Guosheng
Energy & Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA.
School of Polymer Science and Polymer Engineering, The University of Akron, Akron, OH, 44325, USA.
Nat Commun. 2024 Mar 25;15(1):2566. doi: 10.1038/s41467-024-45862-3.
A promising metal-organic complex, iron (Fe)-NTMPA, 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-NTMPA 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·cm². Furthermore, density functional theory unveils two potential coordination structures for Fe-NTMPA 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-NTMPA demonstrates a notably elevated cell voltage of 1 V, enabling a practical energy density of up to 9 Wh/L.
一种有前景的金属有机配合物，即由氯化铁（Fe(III)）和次氮基三（甲基膦酸）（NTMPA）组成的铁（Fe）-NTMPA，被设计用于水性铁氧化还原液流电池。在全电池测试中，将浓缩的Fe-NTMPA阳极电解液（0.67 M）与Fe-CN阴极电解液配对，结果表明在1000次充放电循环中具有出色的循环稳定性，以及显著的性能，包括96%的容量利用率、每循环0.0013%的极低容量衰减率（1000次循环中为1.3%）、高库仑效率和能量效率，分别接近100%和87%，所有这些都是在20 mA·cm²的电流密度下实现的。此外，密度泛函理论揭示了Fe-NTMPA配合物的两种潜在配位结构，增进了对配体配位环境与电子转移动力学之间关系的理解。当与高氧化还原电位的Fe-Dcbpy/CN阴极电解液（2,2'-联吡啶-4,4'-二羧酸（Dcbpy）和氰化物（CN）配体）配对时，Fe-NTMPA显示出显著提高的1 V电池电压，实现了高达9 Wh/L的实际能量密度。
