The sol-gel method was employed in the synthesis of di-urethane cross-linked poly(e-caprolactone) (PCL (530))/siloxane biohybrid ormolytes incorporating either a mixture of lithium triflate (LiCF3SO3) and the ionic liquid (IL) 1-ethyl-3-methyl imidazolium tetrafluoroborate ([Emim] BF4), or solely with [Emim] BF4 or LiCF3SO3. The ormolyte doped with [Emim] BF4 is thermally more stable and exhibits higher ionic conductivity (4 x 10(-4) and 2 x 10(-3)S cm(-1) at 36 and 98 degrees C, respectively) than those containing the LiCF3SO3/[Emim] BF4 mixture or just LiCF3SO3. The three ormolytes were employed in the production of glass/ITO/ormolyte/WO3/ITO/glass electrochromic devices (ECDs) designated as ECD@Y with Y = Li[ Emim] BF4, [Emim] BF4 and Li. The three ECDs displayed fast switching speed (ca. 30 s). ECD@Li-[Emim] BF4 exhibited an electrochromic contrast of 18.4% and an optical density change of 0.11 in the visible region, the coloration efficiency attained at 555nmwas 152 and 80.2cm(2)C(-1) in the "on" and "off" states, respectively, and the open circuit memory was 48 hours. In the "on" state the CIE 1931 color space coordinates were x = 0.29 and y = 0.30, corresponding to blue color. (C) 2015 Elsevier Ltd. All rights reserved.