2,1,3-Benzothiadiazoles(BzNSNs) are a key class of analyte materials for non-aqueous redox flow batteries (RFBs).^{1, 2} Understanding relationships between structural modifications and electrochemical properties is essential for designing energy-dense redox-active organic materials (ROMs) based on the BzNSN scaffold. This talk will describe a series of BzNSN derivatives with various electron-donating or -withdrawing groups as the anolyte materials for non-aqueous RFBs. Systematic investigations have been conducted to elucidate the substituents effects on the solubility, redox potentials, and stability of the corresponding radical anions. Also, the effects of inorganic and organic supporting electrolytes on the stability of the radical anions were extensively studied. Parasitic reactions that involve the sulfur loss and the oligomer formations are shown to restrict the long-term stability of these radical anions, yet the BzNSN molecules are among the leading performing energy-dense ROMs found to-day.

References

1. X. Wei, W. Duan, J. Huang, L. Zhang, B. Li, D. Reed, W. Xu, V. Sprenkle and W. Wang, ACS Energy Letters, 1, 705 (2016).
2. W. Duan, J. Huang, J. A. Kowalski, I. A. Shkrob, M. Vijayakumar, E. Walter, B. Pan, Z. Yang, J. D. Milshtein, B. Li, C. Liao, Z. Zhang, W. Wang, J. Liu, J. S. Moore, F. R. Brushett, L. Zhang and X. Wei, ACS Energy Letters, 2, 1156 (2017).