Electrochromic Properties of Li[sub x]Ni[sub y]O Films Deposited by RF Magnetron Sputtering

Electrochromic properties of a series of films were studied to obtain the films that give a good reversible electrochromic reaction in a nonaqueous electrolyte solution. We paid attention to the lithium content in the films. The films were deposited by radio-frequency (rf) magnetron sputtering with targets under different conditions. The lithium contents were selected by using three different targets. NiO pellets were also used for cosputtering with the targets to finely adjust the lithium content in films. We found that a film gave a high electrochromic coloration efficiency when the lithium content in the film was adjusted to about 0.2. The X-ray diffraction (XRD) study showed that the crystalline film yielded good electrochromic performance, and that the (102) XRD peak was dominant in the films.