Charge Carrier Mobility of Alkali Silicate Glasses Calculated by Molecular Dynamics

• Main Authors: Rebecca S. Welch, Collin James Wilkinson, John Christopher Mauro, Caio Barca Bragatto
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2019-05-01
• Series: Frontiers in Materials
• Subjects: glass; molecular dynamics; ionic conductivity; ionic mobility; ionic conductivity models
• Online Access: https://www.frontiersin.org/article/10.3389/fmats.2019.00121/full

Ionic conductivity is a property of rapidly increasing interest. Various models attempting to explain ionic conductivity of glass systems have shown limited agreement with experimental results; however, none have been comprehensive. By using molecular dynamics simulations, the diffusion of ion species through a network can be directly observed, providing insights into the mechanisms and their relation to ionic conductivity models. In this report, a method of utilizing molecular dynamics simulations is proposed for the study of the ionic mobility of Na, Li, and K ions in binary silicate glasses. Values found for glasses with x = 0.1, x = 0.2, and x = 0.3 alkali content are between 10−5 and 10−4 cm2·s−1·V−1 and did not change significantly with composition or temperature. This is in agreement with the interstitial pair and weak-electrolyte models used to explain ionic conductivity in glasses.