Nanocomposite electrolytes with fumed silica in poly(methyl methacrylate): thermal, rheological and conductivity studies

Composite polymer electrolytes (CPEs), were prepared by adding hydrophilic fumed silica in different proportions upto 5 wt.% to gel polymeric electrolyte (GPE) comprising liquid electrolyte (1 M LiClO4 in propylene carbonate) immobilized with 15 wt.% poly(methyl methacrylate) (PMMA). The effect of fumed silica content in the CPEs on the ionic conductivity and viscosity over a wide temperature range was investigated. The resultant CPEs showed room temperature conductivity (sigma(25)) as high as 3.8 mS cm(-1) along with viscosity value of 3700 P for 2 wt.% SiO2 addition. Fumed silica addition both to the liquid electrolyte and to the GPE exhibits similar conductivity behaviour and this suggests a passive role of PMMA. The shear thinning behaviour, pointing towards easy processablity, high thermal stability and low volatility, makes these CPEs potential candidates as solid-like electrolytes for electrochemical devices. (C) 2004 Elsevier B.V. All rights reserved.