Electrical properties of Ca12Al14O33 synthesised through polymer assisted deposition and glass crystallization routes

Abstract

In this paper, two new methods, polymer assisted deposition (PAD) and glass crystallization (GC) methods were reported for the first time to prepare oxide ion conductor Ca₁₂Al₁₄O₃₃, with their microstructures and electrical properties compared to that of a sample prepared by the traditional solid-state reaction (SSR) method. The results showed that these two new methods are effective for improving ceramic densities and oxide ion conductivities compared to the SSR method, and the ceramic prepared from the GC method in the present work possessed the highest level of ∼94% of the theoretical density and ∼1.0 × 10⁻³ S cm⁻¹ at 900 °C for the bulk conductivity. A new bond valence method was applied to study the oxide ion conducting mechanism, which revealed an exchange process between the free oxide ion and the framework ion, and the wide windows connecting the Ca–Al–O framework cages were shown to be the key factor limiting oxide ion transport.