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Hybrid inorganic-organic polymer electrolyte based on the monomer of organically modified polysiloxane was prepared by UV radiation curing in the presence of liquid electrolyte. The organically modified polysiloxane monomer with acrylate groups at the terminal position was synthesized by hydrolytic condensation of tetramethoxysilane (TMOS) and followed by demethanolation reaction using 2-hydroxyethyl acrylate (2-HEA). The rational formula of the monomer was SiO1.1436(OH)0.01606(OCH3)1.3394(OCH2CH2OCOCH= CH2)0.3574 which was determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and silica analysis. The monomer was polyfunctional with a number average molecular weight of 1185 and a weight average molecular weight of 2292 determined by GPC analysis. The electrochemical properties of the hybrid inorganic-organic polymer electrolyte were determined by ac impedance spectroscopy and cyclic voltammetry. Ionic conductivity was greatly enhanced with increasing amounts of liquid electrolyte. When the polymer electrolyte contained 80 wt% liquid electrolytes, the conductivities were around 3.3 × 10−3 S cm−1 at 21°C and 8.0 × 10−4 S cm−1 even at −23°C. Interface resistance increased initially and reached a steady value after 2 days. Oxidation stability was up to 5.0 V against the lithium reference electrode and electrochemical plating/stripping of lithium on the stainless steel electrode was reversible.

Gel nanocomposite polymer electrolyte (NCPE) was prepared by UV polymerization and thermal polymerization, respectively in the presence of liquid electrolyte with nanosize SiO 2 -contained poly(ethylene glycol) diacrylate (PEGDA) as the monomer. Nanosize SiO 2 -contained PEGDA was synthesized using aqueous colloidal silica as one of starting materials and its viscosity was very low. The partial silanol surface groups of SiO 2 were modified to acrylic group by employing of methacryloxypropyl-trimethoxysilane (MAPTMS), which made the dispersion of nanosize SiO 2 in PEGDA uniform and stable. Compared with the gel polymer electrolyte (GPE) based on PEGDA without nanosize SiO 2 , the ionic conductivity of the gel NCPE was higher and the electrochemical stability and interfacial stability were better, whether it was prepared by UV polymerization or thermal polymerization. It showed oxidation stability up to 5.0 V versus Li/Li + and lithium deposition/dissolution on the stainless steel electrode highly reversible. The applicability of the gel NCPE to lithium polymer batteries was demonstrated by graphite/SPE/LiCoO 2 cell, which was prepared by in situ thermal polymerization. It showed that the discharge capacity was stable with charge–discharge cycling.