US 11,837,767 B2
Electrolyte compositions for redox flow batteries
Chunqing Liu, Arlington Heights, IL (US); Xueliang Dong, Schaumburg, IL (US); Chaoyi Ba, Schaumburg, IL (US); Stuart R. Miller, Arlington Heights, IL (US); and James H. K. Yang, Arlington Heights, IL (US)
Assigned to UOP LLC, Des Plaines, IL (US)
Filed by UOP LLC, Des Plaines, IL (US)
Filed on Jul. 29, 2021, as Appl. No. 17/388,962.
Claims priority of provisional application 63/129,979, filed on Dec. 23, 2020.
Prior Publication US 2022/0200030 A1, Jun. 23, 2022
Int. Cl. H01M 8/18 (2006.01); H01M 8/08 (2016.01)
CPC H01M 8/188 (2013.01) [H01M 8/08 (2013.01); H01M 2300/0005 (2013.01)] 17 Claims
 
1. A redox flow battery system, comprising:
at least one rechargeable cell comprising a positive electrolyte, a negative electrolyte, and an ionically conductive membrane positioned between the positive electrolyte and the negative electrolyte, the positive electrolyte in contact with a positive electrode, and the negative electrolyte in contact with a negative electrode;
the positive electrolyte consisting essentially of water, a first amino acid, an inorganic acid, an iron precursor, a supporting electrolyte, and optionally a boric acid; and
the negative electrolyte consisting essentially of water, the iron precursor, the supporting electrolyte, and a negative electrolyte additive;
wherein the iron precursor is FeCl2, FeCl3, FeSO4, Fe2(SO4)3, FeO, Fe, Fe2O3, or combinations thereof;
wherein the supporting electrolyte is LiCl, NaCl, Na2SO4, KCl, NH4Cl, or combinations thereof; and
wherein the negative electrolyte additive is boric acid and optionally a second amino acid;
wherein the ionically conductive membrane comprises an ionically conductive thin film composite membrane comprising a microporous support membrane and a hydrophilic ionomeric polymer coating layer on a surface of the microporous support membrane, wherein the hydrophilic ionomeric polymer coating layer is ionically conductive; and
wherein the hydrophilic ionomeric polymer comprises a polyphosphoric acid-complexed polysaccharide polymer, a polyphosphoric acid and metal ion-complexed polysaccharide polymer, a metal ion-complexed polysaccharide polymer, a boric acid-complexed polysaccharide polymer, an alginate polymer, an alginic acid polymer, a hyaluronic acid polymer, a boric acid-complexed polyvinyl alcohol polymer, polyphosphoric acid-complexed polyvinyl alcohol polymer, a polyphosphoric acid and metal ion-complexed polyvinyl alcohol polymer, a metal ion-complexed polyvinyl alcohol polymer, a metal ion-complexed poly(acrylic acid) polymer, a boric acid-complexed poly(acrylic acid) polymer, a metal ion-complexed poly(methacrylic acid), a boric acid-complexed poly(methacrylic acid), or combinations thereof; and wherein metal ion is ferric ion or ferrous ion.