Frequency Response of the Mechanochemically Synthesized AgI-Ag2O-B2O3 Superionic Glasses

TL;DR

This study investigates the frequency response and ionic conductivity of mechanochemically synthesized AgI-Ag2O-B2O3 superionic glasses, revealing higher conductivities than melt-quenched samples and unique temperature-dependent activation energy behaviors.

Contribution

It introduces a mechanochemical synthesis method for AgI-Ag2O-B2O3 glasses and characterizes their frequency response and conductivity properties, highlighting novel features compared to traditional methods.

Findings

Higher ionic conductivities than melt-quenched glasses.

Presence of two distinct activation energy regions.

Validation of the UDR relation at lower temperatures.

Abstract

The synthesis of xAgI(1-x)[Ag2O.B2O3] amorphous superionic conductors is done via mechanochemical synthesis route (for x = 0.5 and 0.7). Ionic conductivities of 3 mOhm-1cm-1 for x = 0.5 sample and 5mOhm-1cm-1 for x = 0.7 sample at room temperature, are observed, which are higher than those of the melt quenched glassy samples. Impedance plots (Nyquist plots) are found to be depressed semicircles with a tail at low frequency end. The corresponding equivalent circuit is postulated and each circuit element is related to a physical process. The ac conductivity is analyzed in view of the universal dynamic response (Bode Plots). A unique feature of the mechnochemically synthesized glasses is that their dc conductivity vs. 1/T behavior exhibit two distinct regions with different activation energies. The activation energy for dc conductivity (Edc) and that for ac conductivity (Eac) and the frequency exponent n are found to satisfy the UDR-relation, Eac= (1-n)Edc in the lower temperature regime. In the high temperature region, however, this correlation could not be established due to lack of sac data over the available frequency domain.