A new highly ion conductive organic-inorganic hybrid electrolyte based on the reaction of triblock co-polymer poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) (ED2003) with 3-(glycidyloxypropyl)trimethoxysilane (GLYMO) and followed by co-condensation with 2-methoxy(polyethyleneoxy)propyl trimethoxysilane (MPEOPS) in the presence of LiClO4 was synthesized by a sol-gel process and characterized by a variety of experimental techniques. The maximum ionic conductivities of 1.1 × 10-4 S cm-1 at 30 °C and 6.0 × 10 -4 S cm-1 at 80 °C were obtained for the hybrid electrolyte with a [O]/[Li] ratio of 24. The conductivity mechanism changed from Arrhenius at lower temperatures to Vogel-Tamman-Fulcher (VTF) behavior at higher temperatures. The results of solid-state NMR confirmed the structural framework of the hybrids, and provided a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains. The electrochemical stability window was found to be around 3.7-4.5 V, which is sufficient for electrochemical device applications. Preliminary tests performed with prototype electrochromic devices (ECDs) comprising the hybrid electrolyte with various [O]/[Li] ratios and mesoporous WO3 as the cathode layer are extremely encouraging. The best performance device exhibits an optical density change of 0.58, coloration efficiency of 375 cm2 C -1 and a good cycle life with the hybrid electrolyte with a [O]/[Li] ratio of 24. The present hybrid electrolyte offers a remarkable ionic conductivity and coloration efficiency in the solid state than previously reported organic-inorganic hybrid electrolytes.