posted on 2023-12-22, 14:03authored byTaoyi Kong, Junjie Li, Wei Wang, Xing Zhou, Yihua Xie, Jing Ma, Xianfeng Li, Yonggang Wang
Aqueous
organic redox flow batteries (AORFBs) are considered
a
promising energy storage technology due to the sustainability and
designability of organic active molecules. Despite this, most of AORFBs
suffer from limited stability and low voltage because of the chemical
instability and high redox potential of organic molecules in anolyte.
Herein, we propose a new phenazine derivative, 4,4′-(phenazine-2,3-diylbis(oxy))dibutyric
acid (2,3-O-DBAP), as a water-soluble and chemically
stable anodic active molecules. By combining calculations and experiments,
we demonstrate that 2,3-O-DBAP exhibits a higher
solubility, a lower redox potential (−0.699 V vs SHE), and
greater chemical stability than other O-DBAP isomers.
Then, we demonstrate a long-lasting flow cell with an average discharge
voltage of 1.12 V, a low fade rate of 0.0127%, and a lifespan of 62
days at pH 14 using 2,3-O-DBAP paired with ferri/ferrocyanide.
The negligible self-discharge behavior also verifies the high stability
of 2,3-O-DBAP. These results highlight the importance
of molecular engineering for AORFBs.