Vanadium redox flow batteries (VRFB) store energy in liquid electrolytes containing vanadium ions in four oxidation states. During discharge, the vanadium electrolyte circulates between external tanks and the electrochemical cell stack, where oxidation and reduction reactions convert chemical energy into electricity.
Because both half-cell electrolytes use vanadium, cross-contamination is a reversible imbalance rather than a permanent failure — a key durability advantage over other flow battery chemistries.
Power and Energy Decouple
In a VRFB, power is determined by the size of the cell stack, while energy is determined by the volume of electrolyte in the tanks. This decoupling means developers can scale duration from 2 to 12+ hours simply by adding electrolyte, without changing the electrochemical core.
Cycle Life and Degradation
VRFB systems routinely exceed 20,000 charge-discharge cycles with minimal capacity fade, far beyond lithium-ion's typical 4,000-8,000 cycles. The aqueous vanadium electrolyte is non-flammable, and spent electrolyte retains value as a recoverable vanadium resource at end of life.