Performance Optimization of La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Gd 0.2 CoO 3−δ -Ce 0.8 Sm 0.2 O 1.9 Heterostructured Composite Electrolyte for Semiconductor Ion Fuel Cells

The electrochemical performance of semiconductor ion fuel cells (SIFCs) at intermediate and low temperatures can be significantly enhanced through the synergistic effects between semiconductor materials and ionic conductors, which create fast ion transport channels at their interfaces. In this study, a novel composite electrolyte composed based on a multi-rare-earth high-entropy perovskite oxide (La0.2Pr0.2Nd0.2Sm0.2Gd0.2CoO3−δ, LPNSGC) and samarium-doped ceria (Ce0.8Sm0.2O1.9, SDC) is developed for semiconductor ion fuel cells. A systematic study was conducted on the performance of fuel cells incorporating different proportions of LPNSGC into SDC. Test results indicate that the composite material incorporating 20 wt % LPNSGC (2LPNSGC-8SDC) exhibits outstanding performance, achieving an exceptional maximum power density of 636.19 mW/cm2 and an open-circuit voltage of 1.09 V at 550 °C. The high open-circuit voltage of fuel cells is attributed to the formation of heterojunctions such as Schottky junctions. Simultaneously, the built-in electric field present within the fuel cell provides partial driving force for ion transport. This study highlights the potential of SIFCs for low-temperature solid oxide fuel cell applications and proposes a new material design strategy for advanced energy conversion devices.