Influence of scandium codoping on the stability of barium cerate electrolyte

Abstract

Proton (H+) conducting electrolytes significantly outperform oxide ion (O2–) conducting electrolytes in terms of performance while also costing less to operate the cell. This makes them popular and potential electrolytes in future electrochemical devices such as intermediate temperature solid oxide fuel cells (IT-SOFCs). The standard solid-state reaction method has been utilized in the synthesis of scandium (Sc) co-doped barium zirconium cerate ceramics, BaCe0.8-xZr0.2ScxO3-δ. The powder X-ray diffraction spectra confirmed that the prepared samples are of single phase and have orthorhombic symmetry. The samples were analyzed for thermal stability by employing thermogravimetric analysis (TGA). All samples are stable up to 800 °C, according to TGA performed on dried and pre-hydrated samples—however, the samples under higher partial pressure of water exhibit lower degree of stability. Raman analysis was used to determine the stability of perovskite phase of the studied compositions both before and after TGA. This study showed that most initial phases either persisted or remained stable when the samples were treated at high vapor pressure. The thermal stability increased as the amount of Sc-substitution increased. Also, to investigate how the presence of grains and grain boundaries influenced the total resistance of samples with different Sc concentrations, complex impedance spectroscopy (CIS) was performed.