• redox flow batteries
• solid-boosters

Redox flow batteries (RFB) are a promising technology as a grid-level energy storage system. An RFB is a rechargeable battery where the energy is stored in one or more
electroactive species dissolved into liquid electrolytes. The amount of charge that an RFB can store depends on the solubility of the electroactive species, the solid booster technology, which is being studied in this thesis, plans to increase the energy density of a battery by inserting solid active redox material as millimeter-sized porous beads inside the tanks. The solid boosters studied are composed of prussian white as redox-active material, with small amounts of conductive additive (carbon black) and binder. The electroactive species chosen to interact with the boosters following a Redox Targeting Mechanism is ferrocyanide/ferricyanide. This thesis tries to determine three thermodynamic constants to characterize the system: the formal potential of ferrocyanide/ferricyanide, the formal potential of Prussian white inside the booster phase and an equilibrium pseudo constant that contains within it the effects of the activity coefficients of the species.
By testing the boosters inside a symmetrical battery, the solid redox material can be accessed even up to 51%.
We have found that the composition of the boosters that provide the best capacity performance is 70wt% PW20wt % CB10wt % binder.
We defined a reliable experimental procedure to measure the equilibrium constant of the system, and we proved that solid boosters are effective in increasing the energy density of redox flow batteries.