Fast ion conduction in nanodimensional lithium silicate glasses

Abstract

Nanodimensional glass of composition 35Li₂O·65SiO₂ was grown within the nanochannels of diameter 5.5 nm of mesoporous silica SBA-15 by suitable heat treatment of the required precursor sols. A dc electrical conductivity of 10^–4 S·cm^–1 was measured for the nanoglass at room temperature. This also shows a low activation energy of 0.1 eV for the lithium ion migration. This has been explained as arising due to oxygen ion vacancies caused by the presence of Si²⁺ and Si⁴⁺ species in the mesoporous silica at its interface with the nanoglass. This causes a repulsive interaction between the defects and the lithium ions, thereby reducing the attractive electrostatic force between the nonbridging oxygen ions and the lithium ions. These nanocomposites will be suitable for applications in lithium-ion batteries for storage of renewable energy.