Natural Product Based Small Molecule Redoxmer for Redox Flow Batteries

Abstract

Renewable energy sources such as solar and wind energy are making substantial inroads into the global energy supply as environment-friendly alternatives. To accommodate those renewable resources, grid-scale energy storage technologies have drawn enormous amounts of interest, with redox flow batteries (RFBs) among the leaders in performance. RFBs uses liquid solutions of redox-active chemicals (redoxmers) as energy storage media, rather than the solid-state electrode materials found in conventional batteries. Due to the liquid nature, RFBs feature remarkable flexibilities, including decoupled energy and power that is highly desired for adapting various scales of energy storage requirements. Non-aqueous RFB systems are extensively studied to achieve high voltage and high energy dense batteries. To that end, developing redoxmers with low molecular weight, high solubility in non-aqueous solvents and high stability are actively pursed. Design of redox-active materials based on natural products allows for the development of sustainable and potentially environment-friendly redoxmers for RFBs. Here, we describe the development of a small molecule bipolar redoxmer based on a widely available natural product. We show that a simple modification of the redoxmer leads to high stability in galvanostatic H-cell cycling and high solubility in non-aqueous solvents. The identification and molecular engineering of non-aqueous compatible natural product based redoxmers represent a promising strategy for developing sustainable redoxmers for RFBs. Acknowledgement The research was financially supported by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. The submitted manuscript has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government.