title: Integrating Reverse-Electrodialysis Stacks with Flow Batteries for Improved Energy Recovery from Salinity Gradients and Energy Storage.
abstract: Salinity gradient energy can be directly converted into electrical power by using reverse electrodialysis (RED) and other technologies, but reported power densities have been too low for practical applications. Herein, the RED stack performance was improved by using 2,6-dihydroxyanthraquinone and ferrocyanide as redox couples. These electrolytes were then used in a flow battery to produce an integrated RED stack and flow battery (RED-FB) system capable of capturing, storing, and discharging salinity gradient energy. Energy captured from the RED stack was discharged in the flow battery at a maximum power density of 3.0 kW m-2-anode, which was similar to the flow batteries charged by electrical power and could be used for practical applications. Salinity gradient energy captured from the RED stack was recovered from the electrolytes as electricity with 30 % efficiency, and the maximum energy density of the system was 2.4 kWh m-3-anolyte. The combined RED-FB system overcomes many limitations of previous approaches to capture, store, and use salinity gradient energy from natural or engineered sources.
authors.affiliation: Department of Civil and Environmental Engineering, Penn State University, University Park, PA, 16802, USA.|Department of Civil and Environmental Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Civil and Environmental Engineering, Penn State University, University Park, PA, 16802, USA.
authors.forename: Taeyoung
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Chemical Engineering, Penn State University, University Park, PA, 16802, USA.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Rahimi
authors.affiliation: Department of Civil and Environmental Engineering, Penn State University, University Park, PA, 16802, USA.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Gorski
authors.affiliation: Department of Civil and Environmental Engineering, Penn State University, University Park, PA, 16802, USA.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Logan
mesh_terms: D000880:Anthraquinones; D011211:Electric Power Supplies; D004560:Electricity; D055664:Electrochemical Techniques / Q000379:methods; D004573:Electrolytes; D004736:Energy-Generating Resources; D005295:Ferrocyanides; D010084:Oxidation-Reduction; D054712:Salinity
chemical_list: D000880:Anthraquinones; D004573:Electrolytes; D005295:Ferrocyanides; C020354:hexacyanoferrate II; C034889:2,6-dihydroxyanthraquinone
keywords: energy conversion; flow batteries; reverse electrodialysis; salinity gradient; sustainable chemistry