Superionic conduction of self-assembled heterostructural LSCrF-CeO2 electrolyte for solid oxide fuel cell at 375-550 C

Insufficient ionic conductivity of electrolyte materials and high manufacturing costs create bottlenecks in the commercialization of low-temperature solid oxide fuel cells (LT-SOFCs). Developing the semiconductor-ionic electrolyte represents a new research strategy for high-performance LT-SOFCs because of their attractive ion conduction and associated low polarization loss. In this study, a self-assembly approach is demonstrated by incorporating ABO3 perovskite La0.7Sr0.3Cr0.5Fe0.5O3-delta (LSCrF) into the fluorite structure CeO2, for developing 1LSCrF-xCeO2 composite as semiconductor-ionic heterostructure for LT-SOFCs with superior electrochemical efficiency at the temperature below 550 degrees C and even down to 370 degrees C over unmodified and mechanically mixed samples. Self-assembly enables abundant nanoscale hetero-interfaces accompanied by widely distributed oxygen vacancies, which leads to the superior ionic conductivity of 0.018-0.112 S cm-1, lower activation energy of 0.54 eV and better peak power density of 136-735 mW cm-2 over control samples at 370-550 degrees C, and stable oper-ation for 50 h of resultant LT-SOFCs under a galvanostatic mode. This work highlights the important role of self-assembly in designing heterostructural semiconductor based electrolytes for high-performance LT-SOFCs.