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

Electrochromic properties of a series of Li x Ni y O 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 ͑rf͒ magnetron sputtering with Li x Ni y O targets under different conditions.The lithium contents were selected by using three different Li x Ni y O targets.NiO pellets were also used for cosputtering with the targets to finely adjust the lithium content in Li x Ni y O films.We found that a Li x Ni y O film gave a high electrochromic coloration efficiency when the lithium content in the film was adjusted to about 0.2.The X-ray diffraction ͑XRD͒ study showed that the crystalline Li 2 Ni 8 O 10 film yielded good electrochromic performance, and that the ͑102͒ XRD peak was dominant in the films.