Flow batteries including one or more metals complexed by one or more redox-active ligands are disclosed herein. In a general embodiment, the flow battery includes an electrochemical cell having an anode portion, a cathode portion and a separator disposed between the anode portion and the cathode portion. Each of the anode portion and the cathode portion includes one or more metals complexed by one or more redox-active ligands. The flow battery further includes an anode electrode disposed in the anode portion and a cathode electrode disposed in the cathode portion.
 This invention was made with Government support under Contract No. DE-AC04-94AL85000 between Sandia Corporation and the U.S. Department of Energy. The Government has certain rights in the invention.