Highly soluble Fe(III)-triethanolamine complex relevant for redox flow batteries. (1st April 2019)

• Record Type: Journal Article
• Authors: Lê, Aurore; Floner, Didier; Roisnel, Thierry; Cador, Olivier; Chancelier, Léa; Geneste, Florence
• Is Part Of: Electrochimica acta. Volume 301(2019)
• Page Start: 472
• Page End: 477
• Publication Date: 2019-04-01
• Subjects: All-Fe battery -- Fe complex -- Organometallic electrolyte -- Triethanolamine -- Volumetric capacities; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.02.017
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Fe-triethanolamine is a promising candidate as anolyte for redox flow batteries (RFBs), owning to its low potential, high solubility and low cost. We report here a new dinuclear structure of this complex at solid state when prepared with a stoichiometric amount of triethanolamine and iron in basic medium, whereas more than two equivalents of ligands are usually used to prepare Fe-triethanolamine for RFBs application. We achieve a calibration curve to estimate Fe(III) concentration in solution and coulometric experiments highlight a one-electron reduction process per iron atom, corresponding to the reduction of the two Fe(III) atoms of the dinuclear complex into Fe(II). A solubility higher than 1.2 mol dm −3 can be reached for Fe-triethanolamine with the new synthesis proposed in this work. All-Fe alkaline RFBs implemented with Fe-triethanolamine exhibit good performances in terms of coulombic, voltage and energy efficiencies, and is stable over a hundred of cycles. A power density around 80–120 mW cm −2 is reached and the high solubility of Fe-triethanolamine allows the achievement of high volumetric capacities, superior to 10 Ah dm −3 .