A Systematic Review of SOFC Electrolyte Materials: Classification, Ionic Conduction Mechanism and Performance Regulation

Driven by the global carbon neutrality goal and the traditional energy crisis, solid oxide fuel cells (SOFC) have attracted much attention as an efficient and clean energy conversion technology. The performance of the electrolyte is the core factor determining its efficiency and stability. This article systematically reviews the research progress of four types of electrolytes in solid oxide fuel cells (SOFC): oxide ceramics, sulfides, polymers, and composite electrolytes. It focuses on analysing the crystal structure, ion conduction mechanism, and performance control strategies of each type of electrolyte. It also discusses the influence of defect control and interface engineering on the performance of the electrolyte. At the same time, it clarifies the key role of lattice matching and thermal expansion coefficient compatibility in improving interface stability. The research shows that strategies such as doping modification and composite design can effectively optimize the ion conduction efficiency and stability of the electrolyte, providing technical support for the mid-temperature and long-life development of SOFC and offering references for subsequent research in this field.