Synthesis, dual ionic conductivity and DFT calculations of oxygen migration pathways in NdInO3 perovskite

Lowering the operating temperatures of solid oxide fuel cells (SOFCs) has been a central focus of research. This shift aims to enhance performance, material compatibility and economic viability. Dual ionic conductors play a crucial role in this development, as they directly impact the efficiency and functionality of electrolytes at intermediate temperatures. In this context, we synthesized the rare-earth perovskite NdInO 3 to explore it as a promising proton-conducting oxide for application as an electrolyte in intermediate-temperature solid oxide fuel cells (IT-SOFCs). Rietveld refinement was performed to determine the crystal structure, which was further confirmed by density functional theory (DFT) calculations. The electrical properties of NdInO 3 were investigated using electrochemical impedance spectroscopy under both dry and wet atmospheric conditions. At 550 °C, the total conductivity of the synthesized perovskite in wet air (4.99 × 10 −7 S cm −1 ) is an order of magnitude higher than in dry air (4.24 × 10 −8 S cm −1 ), confirming that proton conductivity makes a significant contribution to the overall conductivity of NdInO 3 at intermediate temperatures. To further interpret these experimental findings, a DFT modeling approach was employed to provide a comprehensive understanding of the oxygen migration processes and to evaluate the migration energy barriers along each pathway in the studied compound. The computed migration energy barriers are in fair agreement with experiments. We find that the HSE06 hybrid functional lowers the migration energy barriers by 5–13% compared to the PBE exchange-correlation functional.