It is worth noting that no leakages have been observed since commissioned. The system shows stable performance and very little capacity loss over the past 12 years, which proves the stability of the vanadium electrolyte and that the vanadium flow battery can have a very long cycle life.
This demonstrates the advantage that the flow batteries employing vanadium chemistry have a very long cycle life. Furthermore, electrochemical impedance spectroscopy analysis was conducted on two of the battery stacks. Some degradation was observed in one of the stacks reflected by the increased charge transfer resistance.
Exposure of the polymeric membrane to the highly oxidative and acidic environment of the vanadium electrolyte can result in membrane deterioration. Furthermore, poor membrane selectivity towards vanadium permeability can lead to faster discharge times of the battery. These areas seek room for improvement to increase battery lifetime.
All vanadium RFB principles The all Vanadium Redox Flow Battery (VRB), was developed in the 1980s by the group of Skyllas-Kazacos at the University of New South Wales , , , .
One disadvantage of vanadium redox-flow batteries is the low volumetric energy storage capacity, limited by the solubilities of the active species in the electrolyte. The cost of vanadium may be acceptable, because it is a relatively abundant material, which exists naturally in ~65 different minerals and fossil fuel deposits.
The reactions proceed in the opposite direction during charge process. The active species are normally dissolved in a strong acid, and the protons transport across the ion-exchange membrane to balance the charge. The standard voltage produced by the vanadium redox-flow battery system is 1.25 V. [1-3]