Sol–gel nonhydrolytic synthesis of a hybrid organic–inorganic electrolyte for application in lithium-ion devices

A new inorganic–organic hybrid electrolyte was synthesized by a nonhydrolytic sol–gel simple route without specific treatment of the reagents. The hybrid ion conductor is prepared with citric acid (CA), tetraethyl-orthosilicate (TEOS) and ethylene glycol (EG), forming polyester chains. The time-consuming drying step, required in most of the chemical syntheses, is not necessary for the preparation of the present hybrid electrolyte, pertaining to the polyelectrolyte class because only Li+ is mobile in the polymeric chain. The effect of the concentration of Li is investigated in terms of the Li-ionic conductivity. The new hybrid conductor is shown to be fully amorphous at room temperature with the vitreous transition temperature around 228 K (−45 °C). The material is solid, transparent and displays an ionic conductivity above 10−5 (Ω cm)−1, besides presenting a great reproducibility of all these characteristics.