“They remain costly, though, with a capital cost of around US $800 per kilowatt-hour, more than twice that of lithium-ion batteries.”
Nian Liu’s Georgia Tech lab replaced flat electrodes and membranes with wires threaded through Nafion tubes and shrank the cell by 75%. The power module is 40% of a flow battery’s cost, and most of its volume is frames, gaskets and plates that do no work. A smaller cell does not touch the tanks or the electrolyte. Flow batteries still have to beat lithium-ion on price, and $800 per kilowatt-hour is a long way from there.