Flow batteries are particularly well-suited for long duration energy storage because of their features of the independent design of power and energy, high safety and long cycle life , . The vanadium flow battery is the ripest technology and is currently at the commercialization and industrialization stage.
Among the numerous all-liquid flow batteries, all-liquid iron-based flow batteries with iron complexes redox couples serving as active material are appropriate for long duration energy storage because of the low cost of the iron electrolyte and the flexible design of power and capacity.
Flow batteries have a long-cycle life because since energy is stored within the electrolytes, the energy capacity (or duration of charge/discharge) is limited only by the amount of electrolyte, and can be increased by adding more electrolyte. Flow batteries, if properly designed, can result in systems with high-cycle life.
The lifetime, limited by the battery stack components, is over 10,000 cycles for the vanadium flow battery. There is negligible loss of efficiency over its lifetime, and it can operate over a relatively wide temperature range. The main benefits of flow batteries can be aggregated into a comprehensive value proposition.
Flow batteries are a type of energy storage technology that stores energy in liquid form instead of in a solid or sealed container. Unlike sealed batteries, they can store energy at high states-of-charge without accelerating degradation. Currently available flow battery technologies include Vanadium Redox, Zinc Iron, and Zinc Bromine.
Nevertheless, the all-iron hybrid flow battery suffered from hydrogen evolution in anode, and the energy is somehow limited by the areal capacity of anode, which brings difficulty for long-duration energy storage.