High-Energy-Density, Aqueous, Metal-Polyiodide Redox Flow Batteries
AssigneeBattelle Memorial Institute
InventorsBin Li, Zimin Nie, Wei Wang, Jun Liu, Vincent L. Sprenkle
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Abstract
Improved metal-based redox flow batteries (RFBs) can utilize a metal and a divalent cation of the metal (M2+) as an active redox couple for a first electrode and electrolyte, respectively, in a first half-cell. For example, the metal can be Zn. The RFBs can also utilize a second electrolyte having I−, anions of Ix (for x≧3), or both in an aqueous solution, wherein the I− and the anions of Ix (for x≧3) compose an active redox couple in a second half-cell.
Claims32
A redox flow battery (RFB) comprising:
- a first electrolyte comprising divalent cations of a metal (M2+) in an aqueous solution and a first electrode comprising the metal (M), wherein M and M2+ compose a first active redox couple at a first half-cell;
- a second electrolyte comprising I−, anions of Ix (x≧3), or both in the aqueous solution, wherein I− and anions of Ix compose a second active redox couple at a second half-cell;
- and
- a membrane or separator between the first and second half-cells.
A redox flow battery (RFB) comprising:
- a first electrolyte comprising Zn2+ in an aqueous solution and a first electrode comprising Zn, wherein the Zn and the Zn2+ compose a first active redox couple at a first half-cell;
- a second electrolyte comprising I−, anions of Ix (x≧3), or both in the aqueous solution, wherein the I− and the anions of Ix compose a second active redox couple at a second half-cell;
- and
- a membrane or separator between the first and second half-cells;
- wherein the RFB has an energy density (based on the positive electrolyte) greater than 60 Wh/L and the aqueous solution contains substantially no iodine.
A method for storing electrical energy in a RFB, the method comprising:
- Providing an electrical source of energy to the RFB;
- Reducing a M2+ electroactive species thereby electrodepositing M on an electrode in a first half-cell, wherein M2+ is a divalent cation of a metal, M;
- Oxidizing a positive electroactive species, I−, to yield one or more anions of Ix (x≧3) in a second half-cell;
- and
- Ceasing the electrical source of energy to prevent formation of iodine.
Dependencies are inferred from the claim text.