Metallic heterostructure enables high performance in low temperature ceramic fuel cells

Heterostructure fuel cells offer substantial advantages, including low-temperature operation and improved ionic conductivity. However, their underlying mechanisms and industrial development remain insufficient to meet essential scientific requirements and the need for rigorous adaptability testing. In this study, we present a metallic heterostructure CeO2/LiCoO2 as a high-performance fuel cell electrolyte, combining density functional theory (DFT) calculations with experimental validation. The CeO2/LiCoO2 heterostructure is synthesized via a simple solid-state reaction. DFT analysis confirms the successful formation of the CeO2/LiCoO2 heterostructure facilitated by the interaction of p-type CeO2 and n-type LiCoO2, with hybridized O-2p and Co-3d orbitals crossing the Fermi level. The electrochemical experiments reveal that the CeO2/LiCoO2 metallic heterostructure fuel cell achieves a remarkable power density of 863 mW·cm−2 and an enhanced ionic conductivity of 0.56 S·cm−1 at 500 °C, underscoring its superior performance. Furthermore, the CeO2/LiCoO2 metallic heterostructure effectively suppress the reduction of Ce4+/Ce3+, significantly enhancing operational stability. This work advances the understanding of metallic heterostructure fuel cells, demonstrating their potential in achieving superior ionic conductivity for practical applications.