Here we report our efforts to explore the mechanisms of capacity fading and to improve the cycling stability of nonaqueous flow batteries based on organic redox-active materials.1-3 Promising organic redox candidates have been identified and structurally tailored to increase their solubilities, redox activities, and chemical stability. A rational molecular design protocol has been proposed and validated for developing stable organic flow batteries. Electrolyte engineering is also found to play a role in tuning the electrochemical performance and stability of nonaqueous flow batteries.
References
(1) X. Wei, W. Xu, J. Huang, L. Zhang, E. Walter, C. Lawrence, M. Vijayakumar, W. A. Henderson, T. Liu, L. Cosimbescu, B. Li, V. Sprenkle, W. Wang, Angew. Chem. Int. Ed. 2015, 54, 8684.
(2) X. Wei,* W. Duan, J. Huang, L. Zhang, B. Li, D. Reed, V. Sprenkle, W. Xu, W. Wang, ACS Energy Lett. 2016, 1, 705.
(3) W. Duan, R. S. Vemuri, J. D. Milshtein, S. Laramie, R. D. Dmello, J. Huang, L. Zhang, D. Hu, M. Vijayakumar, W. Wang, J. Liu, R. M. Darling, L. Thompson, K. Smith, J. S. Moore, F. R. Brushett, X. Wei, J. Mater. Chem. A, 2016, 4, 5448.
Figure 1. The cycling performance of a nonaqueous organic flow battery, showing excellent cycling stability for 50 cycles. The organic redox-active materials are shown.2