Ion migration study in acid-leached soda-lime-silica glass by thermally stimulated depolarization current analysis

Ionic conductivity in silicate glasses is a major issue in the energy sector due to its detrimental effect on electric energy generation and storage and has received increasing attention over the past years. In this study, surface modification of soda-lime-silica (SLS) float glass via acid-leaching treatment (pH 1) was implemented to understand the impact on ionic transport. The acid-leaching treatment created a sodium-depleted "silica-like" structure in the near-surface region with depths of 110 +/- 20 nm for the air-side and 93 +/- 2 nm for the tin-side of the SLS glass. Using the thermally stimulated depolarization current technique, two thermally activated relaxation peaks were found to be associated with different ion migration mechanisms. The first peak (P1) with activation energy of similar to 0.85 eV was attributed to dc conduction of Na+ ions through the glass bulk. A second overlapping peak (P2) at a higher temperature was found to be related to a more limited Na+ ion migration through the acid-leached structure, due to H+ conduction, or a coupled contribution of both mechanisms.