Ionic Transport through Heterogeneous Solids

Abstract

The conductivities of an ionic polycrystalline solid lithium iodide (Lil), covalent polycrystalline lithium aluminium titanium phosphate (LATP) glass-ceramic material, and Y(Sc)SZ with Al₂O₃ and Ba_0.6Sr_0.4TiO₃ (0.6BST) additions were investigated. It was determined that blocking and space charge effects coexist in these heterogeneous solids. However, their magnitudes differ from one system to another. The most pronounced blocking effect was evident in the LATP-Al₂O₃ system, whereas a dominant space charge effect was observed in the Lil-Al₂O₃ system. The higher dielectric constant of 0.6BST enhanced the space charge effect and thus conductivity in the LATP-0.6BST system. In the Y(SC)SZ-Al₂O₃ system the magnitudes of blocking and space charge effects were comparable. The space charge effect was also determined to be strongly temperature dependent.

Keywords:

• Heterogeneous solids
• Ionic conductivity
• Blocking effect
• Space charge effect