Mo-doped and Mo : Sb-doped SnO, were made via the inorganic sol-gel route from the corresponding metal chloride precursors and the films were deposited by dip-coating technique. Films with a thickness of 100-170 nm were made by single dipping and the corresponding charge capacities were in the range 6-11 mC cm-2. The films retained their high optical transparency in the reduced and oxidized state and were promising counter-electrodes in electrochromic devices with transmissive modulation. This was demonstrated by using the films as a counter-electrode in an electrochromic device employing an electrochromic phosphotungstic acid/titanium oxide xerogel film and 0.001 mol dm -3 HCIO, aqueous electrolyte.

Mo : CeO2, Si : CeO2 and Mo : Si : CeO2 films were made by the sol-gel dip-coating technique. XRD investigations of the analogously prepared powders revealed that particle grain size of CeO2 with the addition of Mo, Si or both decreased. FT/IR spectra of the corresponding films showed that no separate Mo-oxide phase was formed while the Si containing CeO2 films had nanocrystallites of ceria as well as amorphous silica. Electrochemical investigations (cyclic voltammetry, chronocoulometry) performed in protic (0.1M LiOH) and aprotic (1M LiC104/propylene carbonate(PC)) electrolytes showed that additions of Mo:, Si: and Mo : Si:-to ceria increased ion storage ability. The suitability of films as optically passive counter electrodes was demonstrated by making electrochromic cells with asymmetric and symmetric configurations using a Li + doped ionic conductor (ormolyte | and an electrochromic tungstophosphoric acid (WPA)/TiO2 gel film.