Enhanced Ionic Conductivity and Durability of Novel Solid Oxide Fuel Cells by Constructing a Heterojunction Based on Transition and Rare Earth Metal Co-doped Ceria

Low temperature performance and durability have been the main indicators of fuel cells. In this work, we develop a novel solid oxide fuel cell (SOFC) by constructing a heterostructure electrolyte based on Gd0.15Ni0.05Ce0.8O2−δ (GNDC) and SnO2, which acquires an open circuit voltage of 1.026 V and a maximum power density (MPD) of 879.4 mW cm–2 at 550 °C. It is demonstrated that the composites are a hybrid ionic and protonic conductor with competent conductivity of 0.124–0.220 S cm–1 at 450–550 °C. Further characterization authenticates the valence state alteration of Ni, creating more oxygen vacancies during the tests. Also, the existence of the Schottky junction is detected to confirm the electron suppressing effects due to the Schottky barrier. These two key points guarantee the superionic conductivity and promising durability of the cells. This work thus presents a creative insight for constructing low temperature solid oxide fuel cells (LT-SOFCs).