A p-n heterostructure composite of NaCrO2 and CeO2 for intermediate temperature solid oxide fuel cells

Abstract

The development of heterostructure electrolytes represents a promising strategy for enhancing the performance of solid oxide fuel cells for the intermediate temperature solid oxide fuel cell (IT-SOFC). In this study, a new p-n semiconductor heterojunction of NaCrO2-CeO2 is proposed as a potential electrolyte for IT-SOFC, which exhibits a high ionic conductivity of 0.173 S·cm−1 and power density of 627.5 mW·cm−2 at 600 °C. A substantial number of oxygen vacancies are revealed in the NaCrO2-CeO2 heterostructure, with protons as the primary charge carriers. Additionally, an apparent P-N rectification effect is observed. Semiconductor band arrangement calculations are performed to elucidate the underlying mechanisms responsible for the exceptional performance of this heterojunction. The results indicate that the heterojunction enhances ion transport, while concurrently inhibiting electron flow, thus significantly contributing to its robust power output and ionic conductivity. This study not only provides a novel perspective on the application of semiconductor theory in ceramic fuel cells, but also advances the scientific understanding of the mechanisms that govern the exceptional performance of heterojunctions in SOFCs.