An electrochromic device comprising: a first substantially transparent substrate having an electrically conductive material associated therewith; a second substrate having an electrically conductive material associated therewith; and an electrochromic medium contained within a chamber positioned between the first and second substrates which comprises: at least one solvent; an anodic material; a cathodic material, wherein both of the anodic and cathodic materials are electroactive and at least one of the anodic and cathodic materials is electrochromic, and wherein at least one of the anodic and cathodic materials is slow-diffusing; and an electron shuttle, wherein the electron shuttle serves to decrease switching time of the electrochromic device relative to the same without the electron shuttle.