Organic non-aqueous cation-based redox flow batteries

摘要

The present invention provides a non-aqueous redox flow battery comprising a negative electrode immersed in a non-aqueous liquid negative electrolyte, a positive electrode immersed in a non-aqueous liquid positive electrolyte, and a cation-permeable separator (e.g., a porous membrane, film, sheet, or panel) between the negative electrolyte from the positive electrolyte. During charging and discharging, the electrolytes are circulated over their respective electrodes. The electrolytes each comprise an electrolyte salt (e.g., a lithium or sodium salt), a transition-metal free redox reactant, and optionally an electrochemically stable organic solvent. Each redox reactant is selected from an organic compound comprising a conjugated unsaturated moiety, a boron cluster compound, and a combination thereof. The organic redox reactant of the positive electrolyte is selected to have a higher redox potential than the redox reactant of the negative electrolyte.

主权项

1. A non-aqueous redox flow battery comprising a negative electrode immersed in a non-aqueous liquid negative electrolyte, a positive electrode immersed in a non-aqueous liquid positive electrolyte, and a cation-permeable separator between the negative and positive electrolytes;
the negative electrode being positioned within a negative electrolyte chamber (“NE chamber”) defined by a first housing and containing the negative electrolyte, the NE chamber connecting with a first negative electrolyte reservoir (“NE reservoir”) and a second NE reservoir such that the first NE reservoir, the NE chamber, and the second NE reservoir can be placed in fluid-flow communication and collectively define a negative electrolyte circulation pathway; a first pump being operably positioned within the negative electrolyte circulation pathway to circulate the negative electrolyte back and forth between the first NE reservoir and the second NE reservoir over the negative electrode; the positive electrode being positioned within a positive electrolyte chamber (“PE chamber”) defined by a second housing and containing the positive electrolyte, the PE chamber connecting with a first positive electrolyte reservoir (“PE reservoir”) and a second PE reservoir such that the first PE reservoir, the PE chamber, and the second PE reservoir can be placed in fluid-flow communication and collectively define a positive electrolyte circulation pathway; a second pump being positioned within the positive electrolyte circulation pathway to circulate the positive electrolyte back and forth between the first PE reservoir and the second PE reservoir over the positive electrode; the negative and positive electrolytes each independently comprising an electrolyte salt, a transition metal-free redox reactant, and optionally an electrochemically stable organic solvent; and the NE chamber and the PE chamber being separated from one another by the cation-permeable separator, such that cations from the electrolyte salt can flow back and forth between the NE chamber and the PE chamber to balance charges resulting from oxidation and reduction of the redox reactants during charging and discharging of the battery, and wherein the cations of the electrolyte salt are selected from Li+ and Na+; wherein the redox reactant of the positive electrolyte has a higher redox potential than the redox reactant of the negative electrolyte, and the redox reactants are independently selected from the group consisting of an organic compound comprising a conjugated unsaturated moiety, a boron cluster compound, and a combination thereof, wherein the conjugated unsaturated moiety is aromatic, non-aromatic, or a combination thereof, and comprises carbon-carbon unsaturated bonds, carbon-heteroatom unsaturated bonds, or a combination of carbon-carbon and carbon-heteroatom unsaturated bonds, and wherein the heteroatom is a non-metallic heteroatom or a metalloid heteroatom; wherein the redox reactant of the negative electrolyte comprises a quinoxaline compound of Formula (I):in which each of R1, R2, R3, R4, R5, and R6 independently is selected from the group consisting of H, alkyl, alkoxy, phenyl, pyridyl, halogen, and amino.