The UniPI work looks at the targets that Flow Batteries need to achieve in order to be competitive within the current long-duration utility-scale storage. The current cost of Vanadium FBs is around 500 $ per kWh, for a battery with 4h discharge time while to be economically viable in the long term, the initial cost target could be set at 150 $ per kWh.
The use of organic materials as electrolytes to address the cost, environmental impact, and safety concerns of FBs looks like a promising option, therefore organic molecules that are water-soluble and synthesized from abundant elements are being explored for use in aqueous organic flow batteries (AOFBs).
The main point of this work presented at IFBF by UniPI PhD student Diana Cremoncini is that AOFBs keep much higher costs than Vanadium ones, because of very high power-related expenses. This is due to the low values of Open Circuit Voltage (OCV), concentration, operational current density, and overall battery efficiency of the organic batteries investigated so far, even assuming a zero active material cost. Finally, the study identifies the key design flow battery parameters to achieve a competitive capital cost for long-duration energy storage applications.