Harnessing Interfacial Electron Transfer in Redox Flow Batteries

Abstract

Redox flow batteries (RFBs) are uniquely suited to mitigating the intermittency of renewable energy sources, such as solar and wind power by storing large quantities of electricity at a modest cost. However, the most technologically mature flow battery systems are still limited in several key performance metrics, including round-trip energy-conversion efficiency and capital cost per unit capacity. Ongoing work in RFB research is directed toward developing novel materials—particularly soluble redox-active molecules for advanced electrolytes. However, another very important consideration in improving the performance of RFBs involves understanding the kinetics of electron transfer between electrolytes and electrodes in the charge-discharge stack. In this targeted review, we outline the challenges associated with translating laboratory measurements of interfacial electron transfer into enhanced practical battery performance, and we highlight several key opportunities for developing advanced RFB electrodes and electrolytes using the tools of catalysis science. Redox flow batteries (RFBs) have garnered increasing attention for their potential to enable the widespread adoption of renewable electricity. However, a critical need associated with the continued development of this technology involves designing electrode-electrolyte interfaces that exhibit rapid, stable electron transfer kinetics. This targeted review outlines key challenges associated with measuring and enhancing the electron transfer kinetics of established and emerging flow battery active materials. We discuss several promising opportunities for advancing flow battery science and technology using the tools of applied electroanalysis and catalysis science. These challenges and opportunities are broadly relevant for future research directed at advancing the commercial adoption of RFBs for grid-scale energy storage. Redox flow batteries (RFBs) have garnered increasing attention for their potential to enable the widespread adoption of renewable electricity. However, a critical need associated with the continued development of this technology involves designing electrode-electrolyte interfaces that exhibit rapid, stable electron transfer kinetics. This targeted review outlines key challenges associated with measuring and enhancing the electron transfer kinetics of established and emerging flow battery active materials. We discuss several promising opportunities for advancing flow battery science and technology using the tools of applied electroanalysis and catalysis science. These challenges and opportunities are broadly relevant for future research directed at advancing the commercial adoption of RFBs for grid-scale energy storage. 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