Coordination compounds having redox non-innocent ligands and flow batteries containing the same

Abstract

Electrolyte solutions for flow batteries and other electrochemical systems can contain an active material capable of transferring more than one electron per oxidation-reduction cycle. Such active materials can include coordination compounds containing a metal center and at least one redox non-innocent ligand. Accordingly, flow batteries can include a first half-cell having a first electrolyte solution therein, where the first electrolyte solution contains a coordination compound having at least one redox non-innocent ligand coordinated to a metal center. Particular redox non-innocent ligands can include those bearing a quinone functional group, such as substituted catecholates bearing a quinone functional group. Some active materials can include compositions containing a coordination compound having at least one redox non-innocent ligand coordinated to a metal center, where the at least one redox non-innocent ligand is a substituted catecholate or a salt thereof bearing a quinone functional group.

Description

[0001] Cross References to Related Applications [0002] Not applicable. [0003] Statement Regarding Federally Sponsored Research or Development [0004] Not applicable technical field [0005] The present disclosure relates generally to energy storage, and more particularly, to flow batteries and other electrochemical systems containing coordination compounds as active materials within electrolyte solutions. Background technique [0006] Electrochemical energy storage systems, such as batteries, supercapacitors, etc., have been widely proposed for large-scale energy storage applications. Various battery designs have been considered for this purpose, including flow batteries. Compared with other types of electrochemical energy storage systems, flow batteries may be advantageous, especially for large-scale applications, because they enable the parameters of power density and energy density to be independent of each other. [0007] Flow batteries generally include nega...

AI Technical Summary

Problems solved by technology

Even when the coordination compound is used at a concentration close to saturation in the electrolyte solution, the energy density may still remain undesirably poor due to the low ratio of transferred electrons per unit of active material on a molar basis.

In addition, operation near the saturation concentration of the active material may be unstable due to precipitation concerns

Not only can precipitation reduce the energy density of flow batteries by reducing the amount of active material available, but precipitation can also be problematic due to potential blockage of cycle paths and damage to other battery components.

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