Cost and price projections of synthetic active materials for redox flow batteries

Abstract

Synthetic organic and organometallic active materials for flow batteries offer a large design space in terms of solubility, redox potential, kinetic activity, and stability. Price is also a key metric. Here we focus on the estimated cost of manufacturing and sales price for synthetic organic negolytes based on anthraquinones and posolytes based on ferrocyanides. We find that derivatives of anthraquinones with simple production processes have an estimated sales price of ~25 $/kWh at an annual production volume of ~10 GWh/y. We also considered contract manufacturing of AQDS at ~200 MWh/y for early-stage commercialization; this results in an estimated sales price of ~40 $/kWh. We find that ferrocyanides, produced in a variety of ways and with several different cations, also result in an estimated sales prices of ~25 $/kWh at ~10 GWh/y. Because low-cost precursors and simple processing result in a couple price of ≥50 $/kWh for synthetic reactants, research should focus on active material equivalent weights of <100 g/eq, an average cell potential of >1.5 V, the avoidance of organic solvents, and precursors that cost no more than a few $/kg. It is also clear that integration with existing production of upstream precursors is the preferred route to cost-effective synthetic active materials.