Designing Stable, Soluble Organic Electro-Active Materials for Non-Aqueous Flow Batteries

Nov 30, 2017 - 8:15 AM -  ES05.04.02
Hynes, Level 3, Room 309
Susan Odom 1 , Aman Preet Kaur 1 , Matthew Casselman 1 , Nuwan Attanayake 1 , Corrine Elliott 1 , Jarrod Milshtein 2 , Jeffrey Kowalski 2 , Sean Parkin 1 , John Anthony 1 , Chad Risko 1 , Fikile Brushett 2
1 , University of Kentucky , Lexington, Kentucky, United States, 2 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Redox flow batteries (RFBs) are promising candidates for grid storage, with a few large-scale systems currently in operation. However, current systems have not met the stringent cost and/or safety requirements needed for widespread implementation. Replacing vanadium with organic compounds may lower materials costs, and utilizing non-aqueous (aprotic) electrolyte solvents, in place of water, could enable a 2- to 3-fold increase in operating voltage. Both features make non-aqueous RFBs candidates for large-scale stationary storage. A limited number of organic compounds have been reported as stable electron donors and acceptors, with even fewer materials being studied as small-molecule two-electron donors and/or two-electron acceptors. Our recent efforts have focused on the development of highly soluble electron donors and acceptors with stable oxidized and reduced states. This presentation will focus on design strategies utilized to increase solubility as well as molecular stability in all relevant states of charge. In particular, we highlight the design, synthesis, and electrochemical analysis of phenothiazine and naphthoquinone derivatives. We show that tactical placement of substituents leads to improved stability of doubly oxidized and doubly reduced species, whilst retaining atom economy and high solubility.