A half-metallic heterostructure fuel cell with high performance

Heterostructure fuel cells for renewable energy utilization are promising as one of the most important next-generation solid oxide fuel cells (SOFCs) at low operating temperatures, due to electron insulation and enhanced interface ionic conduction, but it is limited by few types of proper heterostructures and unclear synergism mechanisms. Herein, we propose a new-type half-metallic heterostructure fuel cell with high performance. Two new stable half-metallic heterostructures of CeO₂/LiNiO₂ and CeO₂/Li₂NiO₂ are successfully constructed via facile solid-state-reaction experiments combined with density functional theory (DFT) calculations, which exhibit only one spin direction of electrons at the Fermi level, and its electrons achieve 100 % spin polarization rate at the Fermi level. Both CeO₂/Li₂NiO₂ and CeO₂/LiNiO₂ half-metallic heterostructure fuel cells reach normal open circuit voltages (OCVs) of 1.04 V and 1.05 V, enhanced maximum power densities of 828 mW cm⁻² and 984 mW cm⁻² with a high ionic conductivity of 0.29 S cm⁻¹ and 0.32 S cm⁻¹ at 500 °C, respectively. The higher output performance of CeO₂/LiNiO₂ half-metallic heterostructure fuel cell is ascribed to its higher strength of density of state and interface local electric field, as DFT analysis demonstrated. These results have demonstrated a promising half-metallic heterostructure fuel cell, suggesting an understanding direction of ionic-electronic synergism mechanisms.