Activated carbon as a redox flow battery

With the increase of renewable wind and solar energy, there is a need for long-term, low-cost energy storage systems to buffer their variable output. Redox flow batteries (RFBs) have the potential to store large amounts of energy for on-demand power generation and long-duration discharge. RFBs consist of two soluble redox couples stored in separate tanks that are flowed through a stack during charge/discharge, decoupling the battery’s power and energy capacity to meet custom scaling requirements. Despite this flexibility, RFBs currently have low energy densities compared to rechargeable lithium-ion batteries due to poor aqueous solubility of the active species and/or low voltage outputs. Robust, high voltage catholytes are needed in RFBs. The catholyte iron (II/III) tris-2,2’-bipyridine,