Correlation between floppy to rigid transitions and non-Arrhenius conductivity in glasses

TL;DR

This study links the transition from floppy to rigid network structures in potassium silicate glasses to non-Arrhenius ionic conductivity behavior, highlighting the importance of network rigidity in glass electrolyte conduction.

Contribution

It demonstrates the correlation between network rigidity transitions and ionic conductivity behavior, using constraint theory to explain non-Arrhenius effects in glasses.

Findings

Conductivity increases rapidly beyond a critical potassium oxide concentration.

Annealing restores Arrhenius behavior by densifying the glass network.

Conductivity follows a percolation law at the critical concentration.

Abstract

Non-Arrhenius behaviour and fast increase of the ionic conductivity is observed for a number of potassium silicate glasses $(1-x)SiO_2-xK_2O$ with potassium oxide concentration larger than a certain value $x=x_c=0.14$. Recovering of Arrhenius behaviour is provided by the annealing that enhances densification. Conductivity furthermore obeys a percolation law with the same critical concentration $x_c$. These various results are the manifestation of the floppy or rigid nature of the network and can be analyzed with constraint theory. They underscore the key role played by network rigidity for the understanding of conduction and saturation effects in glassy electrolytes.