1. Indolo[2,3‑b]quinoxaline as a Low Reduction Potential and High Stability Anolyte Scaffold for Nonaqueous Redox Flow Batteries
- Author
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Zhang, Wenhao, Walser-Kuntz, Ryan, Tracy, Jacob S, Schramm, Tim K, Shee, James, Head-Gordon, Martin, Chen, Gan, Helms, Brett A, Sanford, Melanie S, and Toste, F Dean
- Subjects
Engineering ,Materials Engineering ,Chemical Sciences ,Physical Chemistry ,Affordable and Clean Energy ,Climate Action ,CSD-46-All CSGB ,General Chemistry ,Chemical sciences - Abstract
Redox flow batteries (RFBs) are a promising stationary energy storage technology for leveling power supply from intermittent renewable energy sources with demand. A central objective for the development of practical, scalable RFBs is to identify affordable and high-performance redox-active molecules as storage materials. Herein, we report the design, synthesis, and evaluation of a new organic scaffold, indolo[2,3-b]quinoxaline, for highly stable, low-reduction potential, and high-solubility anolytes for nonaqueous redox flow batteries (NARFBs). The mixture of 2- and 3-(tert-butyl)-6-(2-methoxyethyl)-6H-indolo[2,3-b]quinoxaline exhibits a low reduction potential (-2.01 V vs Fc/Fc+), high solubility (>2.7 M in acetonitrile), and remarkable stability (99.86% capacity retention over 49.5 h (202 cycles) of H-cell cycling). This anolyte was paired with N-(2-(2-methoxyethoxy)-ethyl)phenothiazine (MEEPT) to achieve a 2.3 V all-organic NARFB exhibiting 95.8% capacity retention over 75.1 h (120 cycles) of cycling.
- Published
- 2023