Nanostructured ionic conductors: A study of Vycor®7930–LiI composites

A series of three Vycor glass/LiI composites were prepared by impregnating molten LiI into a porous Vycor®7930 powdered glass. X-ray diffraction showed the presence of LiI and LiI, H2O crystallites of about 100 nm in size. Scanning electron microscopy confirmed that an optimisation of heat treatment could lead to a composite with optimal coating and filling of the pores of the matrix. An increase in the pore size, unavoidable and due to the residual water content of the Vycor, was measured by Hg porosimetry. Nevertheless the conductivity of the composites was increased compared to that of pure LiI, with a gain of two orders of magnitude for the best conductor, i.e. 0.5LiI–0.5Vycor.