Conjugated Bipolar Redox-Active Electrolyte for Symmetric Redox Flow Battery

Organic non-aqueous redox-flow batteries (O-NRFBs) are gaining traction as viable alternatives for long-term, low-cost stationary energy storage with a wide potential window.[1] The symmetric O-NRFBs with single bipolar electrochemically active molecule as both anolyte and catholyte (i.e. bipolar redoxmer) helps to mitigate permanent cross-contamination and capacity fading.[2] However, symmetric O-NRFBs with bipolar molecules are hampered by the scarcity of redox active molecules capable of serving as a stable bipolar redoxmer with high cell potential and unpredictable side reactions.[3] This study proposes the π-conjugation of electrochemical active electron donors and electron acceptor which leads to the possible control over direct electronic perturbation between acceptor-donor to form new type of redox molecules. This study aims designing of benzothiadiazole based conjugated bipolar redox-active molecule with high potential window and high stability. [1]. M. Li, S. A. Odom, A. R. Pancoast, L. A. Robertson, T. P. Vaid, G. Agarwal, H. A. Doan, Y. Wang, T. M. Suduwella, S. R. Bheemireddy, R. H. Ewoldt, R. S. Assary, L. Zhang, M. S. Sigman, and S. D. Minteer, “Experimental protocols for studying organic non-aqueous redox flow batteries,” ACS Energy Lett., 2021, 6, 11, 3932–3943. [2]. M. Li, J. Case, and S. D. Minteer, “Bipolar redox-active molecules in non-aqueous organic redox flow batteries: status and challenges,” ChemElectroChem, 2021, 8, 1215–123. [3] M. Li, G. Agarwal, I. A. Shkrob, R. T. VanderLinden, J. Case, M. Prater, Z. Rhodes, R. S. Assary and S. D. Minteer, “Critical role of structural order in bipolar redox-active molecules for organic redox flow batteries,” J. Mater. Chem. A, 2021, 9, 23563-23573.