Proton transport in unsintered BaCe0.8Y0.2O3–α for easily prepared electrochemical devices

BaCe_0.8Y_0.2O_3–α ceramics exhibit superior conductivity among related materials. However, the high-temperature sintering makes it difficult to prepare electrochemical devices with a BaCe_0.8Y_0.2O_3–α multilayer film, and very few studies have examined the conductivity and transport properties of unsintered BaCe_0.8Y_0.2O_3–α. In nominally dry conditions, the instability of this material in a water-containing atmosphere can be minimized, allowing the unsintered BaCe_0.8Y_0.2O_3–α to be applied in some particular test environment as a component of electrochemical devices. Hence, the conductivity of unsintered BaCe_0.8Y_0.2O_3–α in dry conditions was measured via AC impedance spectroscopy in the temperature range of 500–800 °C. The unsintered BaCe_0.8Y_0.2O_3–α exhibits high conductivity and hydration ability, as well as low proton activation energy. In addition, it shows high oxygen vacancy and low proton transport numbers at high temperature, limited by its grain boundaries. This work provides insights into the conductivity and proton transport of unsintered BaCe_0.8Y_0.2O_3–α and demonstrates its potential as a proton-conducting electrolyte.