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

Abstract

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-δ (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 °C and even down to 370 °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 °C, and stable operation 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.