In redox flow systems, the flow distribution, reactive environment, and transport of species are critical for obtaining high electrochemical performance, which can be controlled by the topology and properties of the electrodes, including electronic conductivity, thickness, porosity, active surface area, electrode microstructure, surface morphology, surface composition and functional groups determining the mass transfer characteristics of the system which can dramatically affect the efficiency of the stack. In order to reduce charge transfer, ohmic, and mass transfer losses, a favorable electrode structure should contain high surface areas, high electronic conductivity, and elevated permeability, respectively. Although these attributes are all desirable, their relative significance varies depending on the redox couple, electrolyte composition, and operational parameters .