Sol-Gel Non-hydrolytic Synthesis of a Nanocomposite Electrolyte for Application in Lithium-ion Devices

摘要

A new nanocomposite electrolyte was synthesized using a simple non-hydrolytic sol-gel route without specific treatment of the reagents. The nanocomposite ion conductor was prepared with citric acid, tetraethyl orthosilicate and ethylene glycol, forming polyester chains. The time-consuming drying step that is a necessary part of most chemical syntheses was not required in the preparation of the present nanocomposite electrolyte of the polyelectrolyte class, because only Li~+ is mobile in the polymeric chain. The effects of the concentration of Li, SiO_2 and SnO_2 nanoparticles were investigated in terms of L_1~+ ionic conductivity. Conductivity measurements as a function of the metal oxide nanocrystal content in the nanocomposite revealed a significant increase in conductivity at approximately 5 and 10 wt % of nanoparticles. The new nanocomposite conductor proved to be fully amorphous at room temperature, with a vitreous transition temperature of approximately 228K (-45℃). The material is solid and transparent, displaying an ionic conductivity of 10~(-4) to 10~(-5) (O.cm)~(-1) at room temperature presenting excellent reproducibility of all these characteristics. Cyclic voltammetry measurements indicate that the hybrid electrolyte possesses outstanding electrochemical stability.