A Novel Iron Chloride Red-Ox Concentration Flow Cell Battery (ICFB) Concept; Power and Electrode Optimization

For renewable energies to succeed in replacing fossil fuels, large-scale and affordable solutions are needed for short and long-term energy storage. A potentially inexpensive approach of storing large amounts of energy is through the use of a concentration flow cell that is based on cheap and abundant materials. Here, we propose to use aqueous iron chloride as a reacting solvent on carbon electrodes. We suggest to use it in a red-ox concentration flow cell with two compartments separated by a hydrocarbon-based membrane. In both compartments the red-ox couple of iron II and III reacts, oxidation at the anode and reduction at the cathode. When charging, a concentration difference between the two species grows. When discharging, this concentration difference between iron II and iron III is used to drive the reaction. In this respect it is a concentration driven flow cell redox battery using iron chloride in both solutions. Here, we investigate material combinations, power, and concentration relations.

Automated summary

In order to replace fossil fuels with renewable energies, large-scale and cost-effective energy storage solutions are necessary. By utilizing aqueous iron chloride in a concentration flow cell with a hydrocarbon-based membrane separating two compartments, energy can be stored through redox reactions.