110th Anniversary: Unleashing the Full Potential of Quinones for High Performance Aqueous Organic Flow Battery

Aqueous organic flow batteries (AOFBs) are promising energy storage solutions to counteract the intermittent and fluctuating nature of renewable energy. However, we have limited options of electrolyte chemistry and we discarded many organic compounds because of their sluggish electrochemical kinetics, which would compromise the power capability of an AOFB. Here, exemplified by 2,5-dihydroxy-3,6-dimethyl-1,4-benzoquinone (DMBQ), we present two approaches including engineering the molecular structure and utilizing an inexpensive catalyst to enhance the electrochemical kinetics of benzoquinones with the ultimate purpose of diminishing the electron transfer barrier thereby increasing the power capability of the AOFB. We show that, by exploiting these strategies, the electron transfer resistance could be reduced by 48.1%, or 55.8%, respectively, thereby leading to a 49.4% or 60.7% increase in the peak power density of a flowing cell. We believe our strategy could be extended to the full family of quinones and that it benefits further exploration of quinone-based high performance AOFBs.