Thin films of lithium nickel oxide were deposited by rf sputtering from a stoichiometric LiNiO2 target. The films exhibit excellent reversibility in the potential range 1.1 to 3.8 V versus Li/Li+ and could be cycled in a liquid electrolyte half cell with a switching range Delta T-Photopic close to 70%. The photopic coloration efficiency of this anodically coloring material was typically -30 to -40 cm(2) C-1. The switching performance of a device utilizing a lithium nickel oxide film as counter electrode and a tungsten oxide electrochromic film is reported. The device switched from 75% photopic transmittance to 2%, with color neutrality and a coloration efficiency of 65 cm(2) C-1.