Counter electrode for electrochromic devices

An integrated deposition system for fabricating an electrochromic device stack, the system comprising:

• a plurality of deposition stations aligned in series and interconnected and operable to pass a substrate from one station to the next without exposing the substrate to an external environment, wherein the plurality of deposition stations comprise
• (i) a first deposition station containing one or more material sources for depositing a cathodically coloring layer;
• (ii) a second deposition station containing one or more material sources for depositing an anodically coloring layer comprising nickel tungsten tantalum oxide, wherein the nickel tungsten tantalum oxide has an atomic ratio of Ni:(W+Ta) that is between 1.8:1 and 3:1, and has an atomic ratio of W:Ta that is between 1:1 and 2:1;
• and
• a controller containing program instructions for passing the substrate through the plurality of deposition stations in a manner that deposits on the substrate (i) the cathodically coloring layer, and (ii) two or more sub-layers of the anodically coloring layer to form a stack comprising at least the cathodically coloring layer and the anodically coloring layer, wherein the two or more sub-layers have different compositions and/or different relative concentration, and wherein a first sub-layer of the two or more sub-layers comprises a binary metal oxide and a second sub-layer of the two or more sub-layers comprises a ternary metal oxide.