Enhanced performance of medium-temperature solid oxide fuel cells using CaSnO3-ZnO heterostructure as electrolyte

The advancement of novel heterostructure electrolytes and the enhancement of solid oxide fuel cell (SOFC) performance represent a promising strategy for developing medium-temperature SOFCs. This study focuses on synthesizing CaSnO₃ via the sol-gel technique and fabricating CaSnO₃-ZnO composites to serve as electrolytes for medium-temperature SOFCs. At 550 °C, the 2Ca8Zn composite demonstrated an ionic conductivity of 0.204 S cm⁻¹, a peak power density of 700 mW cm⁻², and intermittent durability lasting up to 24 h under identical thermal conditions. Upon further investigation of the energy band structure, it has been revealed that CaSnO₃-ZnO composites are promising candidates for serving as electrolytes in medium-temperature SOFCs. The findings indicate that the combination of calcium and zinc oxides can form n-n heterojunctions within the material, which enhance ionic conductivity by creating space charge regions, while simultaneously suppressing electronic conductivity. Consequently, CaSnO₃-ZnO nanocomposites are anticipated to pave the way for advancements in intermediate-temperature solid oxide fuel cells.