Electrochromic elements, materials for use in such element, processes

Abstract

An electrochromic element useful in an electrochromic glass or mirror device and a process for making such element. The element is a five-layered structure including an electrolyte ion conducting layer interposed between first and second inorganic electrochromic layers which are interposed between a pair of conductive electrodes. The first and second inorganic electrochromic layers are different and are capable of exhibiting color-forming properties complementary to one another upon the incorporation of an alkali metal or Ag ion, a mixture of alkali metal or Ag ions or a mixture of alkali metal or Ag and hydrogen ions. The electrolyte ion conducting layer may be a copolymer of ethylene oxide, butylene oxide or methyl glycidyl ether, and optionally a small amount of allyl glycidyl ether, along with an ionizable salt, or may be a polyurethane gel forming by reacting the copolymer with triisocyanate, along with an ionizable salt. The second inorganic electrochromic layer comprises a transition metal oxide which exhibits a color change when shifting between the +2 and +3 valence states. The second inorganic electrochromic layer may be produced by an electrochemical process, a chemical process, or by a physical process. The electrochromic element may also comprise a plurality of five-layer structure in tandem, each pair separated by a substrate.