Sensitivity of Capacity Fade in Vanadium Redox Flow Battery to Electrolyte Impurity Content.

Autor: Pichugov R; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia., Loktionov P; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia., Verakso D; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia., Pustovalova A; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia.; Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30, bld. 1, 121205, Moscow, Russia., Chikin D; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia.; Lomonosov Moscow State University, Leninskiye Gory 1, 119991, Moscow, Russia., Antipov A; Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047, Moscow, Russia.
Jazyk: angličtina
Zdroj: ChemPlusChem [Chempluschem] 2024 Dec; Vol. 89 (12), pp. e202400372. Date of Electronic Publication: 2024 Oct 21.
DOI: 10.1002/cplu.202400372
Abstrakt: The gradual capacity decrease of vanadium redox flow battery (VRFB) over long-term charge-discharge cycling is determined by electrolyte degradation. While it was initially believed that this degradation was solely caused by crossover, recent research suggests that oxidative imbalance induced by hydrogen evolution reaction (HER) also plays a significant role. In this work by using vanadium pentoxides with different impurities content, we prepared three grades of vanadium electrolyte. By measuring electrochemical properties on carbon felt electrode in three-electrode cell and VRFB membrane-electrode assembly we evaluate the influence of impurity content on battery polarization and rate of side reactions which is indicated by the increase of average oxidation state (AOS) during charge-discharge tests and varies from 0.061 to 0.027 day -1 for electrolytes made from 99.1 and 99.9 wt % V 2 O 5 . We found that increase of AOS correlates with the increase of open-circuit voltage of VRFB in the discharged state ranging from 9.6 to 14.9 mV day -1 for highest and lowest electrolyte purity levels, respectively. While AOS increase is significant, it does not solely determine capacity fade. It is demonstrated that the presence of vanadium crossover decreases capacity fade, i. e. levels the contribution of side reactions on capacity drop.
(© 2024 Wiley-VCH GmbH.)
Databáze: MEDLINE
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