Close-to-neutral operation enables high capacity retention: long-term testing of…

Presenter: Filippo Fenini
Title: Close-to-neutral operation enables high capacity retention: long-term testing of an aqueous organic-inorganic redox flow battery
Affiliation: Aarhus University

Abstract

Aqueous Organic redox flow batteries (AORFB) are emerging as large-scale storage technology, as organic redox species have the potential to be a low cost commodity with broad geographical availability. Capacity fade mechanisms in AORFB are attributable to decomposition pathways of the active molecules. Such reactions are often catalyzed by either basic or acidic environment, yet most of AORFB reported are operated in such conditions, to achieve the highest solubility (energy density). Here we report a close-to-neutral organic-inorganic battery with excellent cyclability and high durability. 2,7-AQDS is used as negative electrolyte and Fe(CN)64- as positive electrolyte. It will be shown how the energy density of the negative side can be increased by the addition of an inexpensive co-electrolyte. The tests indicate how time rather than number of cycles is responsible of the capacity fade. After 1000 h of cycling, the negative side of the AORFB still exhibit high capacity retent  ion.

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