| Abstract: | Nonaqueous redox flow batteries (RFB) hold the potential for high energy
density grid scale storage, though are often limited by the solubility of
the redox-active species in their electrolytes. A systematic approach
enables an increase the concentration of redox-active species in
electrolytes for nonaqueous RFB, starting from a
metal-coordination-cation-based ionic liquid. As an example, starting
with an ionic liquid consisting of a metal coordination cation (MetIL),
ferrocene-containing ligands and iodide anions can be substituted into
the original MetIL structure, enabling a nearly 4.times. increase in
capacity compared to original MetIL structure. Application of this
strategy to other chemistries, optimizing electrolyte melting point and
conductivity could yield >10 M redox-active electrons. |