REDOX FLOW BATTERY

A redox flow battery, comprising a first electrolyte storage (), a second electrolyte storage (), an electrochemical cell connected to said first and second electrolyte storages (), wherein said electrochemical cell comprises a first half-cell and a second half-cell, wherein said first half-cell comprises a cathode (), wherein said second half-cell comprises an anode (), wherein said first and second half-cells are separated from each other by an ion exchange membrane (), wherein said first electrolyte storage comprises an aqueous solution comprising an iron complex of a compound of formula I and stereoisomers of compound of formula I.