Copper(II) tungsten oxide nanopowder is used for supercapacitor applications. Nano-sized CuWO4 thin films have been fabricated by radio-frequency (R.F.) sputtering deposition, and are used as positive electrode with both LiClO4 liquid electrolyte and LiPON solid electrolyte in rechargeable lithium batteries. Thin films of copper tungstate is used for nitric oxide sensing.