Vanadium Redox Flow Batteries are the most marketed flow batteries at present, due to a number of advantages they provide over other chemistries, despite their limited energy and power densities. Since they use vanadium at both electrodes, they do not suffer cross-contamination issues. For the same reason, they have unparalleled cycle lives (15,000–20,000 cycles), which in turns results in record levelized cost of energy (LCOE, i.e. the system cost divided by the usable energy, the cycle life, and round-trip efficiency), which are in the order of a few tens of $ cents or € cents per kWh, namely much lower than other solid-state batteries and not so far from the targets of $0.05 and €0.05, stated by US and EC government agencies.