Enhanced Ionic Conduction Observed for Ordered-Mesoporous Alumina-Ionic Conductor Composites

摘要

Ordered-mesoporous Al_2O_3 was synthesized by the sol-gel method using neutral surfactants as templates. The pore size can be controlled over the range of 2.8～12.5 nm by using different surfactant copolymers and by different synthetic conditions. By utilizing cyclohexane as a co-solvent, mesoporous Al_2O_3 having relatively mono-dispersed particle size was obtained. Composites composed of the synthesized mesoporous Al_2O_3 and the lithium ion conductor (LiI) was prepared. The dc electrical conductivity of 50LiI·50(mesoporous Al_2O_3) was 2.6x10~(-4) S cm~(-1) at room temperature, which is more than 100 times higher than that of pure Lil. The pore size dependence of the conductivity of LiI-mesoporous Al_2O_3 composite was examined. A systematic dependence of conductivity upon pore size was observed, in which the conductivity increased with decreasing the pore size.