Catalytic membrane with high ion–electron conduction made of strongly correlated perovskite LaNiO₃ and Ce_0.8Sm_0.2O_2-δ for fuel cells

The strongly correlated perovskites RNiO₃ (R = rare earth) have been featured of appreciable ionic conduction and catalytic activity in solid oxide fuel cells (SOFCs) in recent years. In this study, to tap more potentials of RNiO₃, we promote a typical member from this material family, LaNiO₃ (LNO) for SOFC electrolyte membrane use in a form of composite with Ce_0.8Sm_0.2O_2-δ (SDC) by taking advantage of their ion-conducting and catalytic capabilities. The developed composite materials are found to be competent electrolyte membranes possessing improved ionic conductivities along with good auxiliary catalytic effect to the cell electrode reaction, realizing good fuel cell power outputs of 268–688 mW cm⁻² and high OCV above 1.0 V at 530 °C. Comparative study reveals that the 5LNO-5SDC composite gains the highest ionic conductivity (0.203 S cm⁻¹ at 530 °C) and results in the lowest electrode polarization resistance (0.2973 Ω cm² at 530 °C). It is believed the catalytic activity of 5LNO-5SDC is mainly inherited from the LNO phase while benefiting from the high mixed ion–electron conduction. To manifest the reliability of the material, further studies in terms of rectification curve and cell durability tests have been carried out, certifying the Schottky junction effect and material stability in the fuel cells.