The effect of electrolyte and additive concentration on zinc–nickel flow cell performance. (20th January 2021)

• Record Type: Journal Article
• Authors: Trudgeon, David P.; Li, Xiaohong
• Is Part Of: Electrochimica acta. Volume 367(2021)
• Publication Date: 2021-01-20
• Subjects: Electrolyte additive -- Zinc electrode -- Zinc electrodeposition -- Redox flow battery; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2020.137479
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: This work aims to identify a suitable electrolyte composition for the operation of a zinc–nickel flow cell at ambient temperature. The effect of varying electrolyte composition containing KOH, ZnO, tetraethylammonium hydroxide (TEAH) or tetrabutylammonium bromide (TEAB) electrolyte additives are investigated. A 15 mM concentration of TEAH is found to provide smooth and compact zinc depositions. Increasing concentrations of KOH are found to be detrimental to voltaic efficiency, with coulombic efficiency peaking in 6 M KOH. The coulombic efficiencies of both zinc and nickel electrodes improve with ZnO concentration. Galvanostatic zinc–nickel flow cell cycling yields the highest efficiencies in an electrolyte of 6 M KOH with 0.5 M ZnO and 15 mM TEAH, with coulombic, voltaic and energy efficiencies of 98%, 88% and 86%, respectively, over 70 stable charge/discharge cycles.