A subtractive approach to molecular engineering of dimethoxybenzene-based redox materials for non-aqueous flow batteriesElectronic supplementary information (ESI) available: Acronyms of chemicals, experimental section, commercial source of DB, and MDB, synthetic procedure of 23DDB, 25DDB and 26DDB, cyclic voltammograms of MDB, 26DDB, Randle-Sevcik plots of DBBB, 25DDB, 23DDB, and 1H NMR and 13C NMR spectra of 23DDB, 25DDB, 26DDB. See DOI: 10.1039/c5ta02380g

• Main Authors: Huang, Jinhua, Su, Liang, Kowalski, Jeffrey A, Barton, John L, Ferrandon, Magali, Burrell, Anthony K, Brushett, Fikile R, Zhang, Lu
• Format: Journal Article
• Language: English
• Published: 14.07.2015
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/c5ta02380g

The development of new high capacity redox active materials is key to realizing the potential of non-aqueous redox flow batteries (RFBs). In this paper, a series of substituted 1,4-dimethoxybenzene based redox active molecules have been developed via a subtractive design approach. Five molecules have been proposed and developed by removing or reducing the bulky substituent groups of DBBB (2,5-di- tert -butyl-1,4-bis(2-methoxyethoxy)benzene), a successful overcharge protection material for lithium-ion batteries. Of these derivatives, 2,3-dimethyl-1,4-dimethoxybenzene (23DDB) and 2,5-dimethyl-1,4-dimethoxybenzene (25DDB) are particularly promising as they demonstrate favorable electrochemical characteristics at gravimetric capacities (161 mA h g −1 ) that approach the stability limit of chemically reversible dimethoxybenzene based structures. Diffusivity, solubility, and galvanostatic cycling results indicate that both 23DDB and 25DDB molecules have promise for non-aqueous RFBs. The development of new high capacity redox active materials is key to realizing the potential of non-aqueous redox flow batteries (RFBs).