Effect of Li2O composition and temperature on the ionic conductivity of lithium-borate-silicate glasses containing gold nanoparticles using electrochemical impedance spectroscopy

Abstract

This research systematically investigates the conductivity properties of a lithium-borate-silicate glass containing varying amounts of Li2O (30 to 50 mol %) in the presence and absence of a fixed concentration of gold nanoparticles (0.05 M). Three techniques were used to characterize the glass material: Electrochemical Impedance Spectroscopy, X-ray diffraction, and Differential Scanning Calorimetry. Impedance spectra were recorded at temperatures of 100 °C, 140 °C, and 200 °C, and the results were analyzed qualitatively and quantitatively using models based on the equivalent circuit approach. It was observed that below a critical concentration of Li2O, namely 35 mol %, the conductivity behavior exhibits a single relaxation process. However, above the critical concentration, the materials present two relaxation processes associated with changes in morphology. Impedance measurements also evaluate the DC and AC conductivity properties of the glasses. Interestingly, regardless of the morphology, conduction in the glasses appears to be thermally activated, with the conduction mechanism being controlled by polaron hopping in a correlated barrier. There is no evidence suggesting that the gold nanoparticles play a significant role in determining the conduction properties of the glasses, at least within the concentration range studied here.