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.