Electrochromic LixWO_3/polymer laminate/LiyV_2O_5 device: toward an all-solid-state smart window

Abstract

We introduce a laminate two-layer approach to electrochromic smart windows. It incorporates two glass panes, each having a two-layer coating, laminated by a transparent adhesive solid polymer electrolyte. Each coating has a transparent conducting base layer (In₂O₃:Sn) and a top layer of an ion-insertion compound (based on WO₃ or V₂O₅). The layers were made by evaporation or sputtering. Cyclic voltammetry in liquid electrolytes and spectrophotometry were used to characterize the layers. A novel electrolyte was developed: it comprised a methyl methacrylate network incorporating poly(propylene glycol) complexed with lithium perchlorate. Initial optical data are reported for laminated devices having an active electrochromic Li_xWO₃ layer and a passive Li_yV₂O₅ counter electrode.