Ultra‐Fast Microwave‐Assisted Volumetric Heating Engineered Defect‐Free Ceria/Zirconia Bilayer Electrolytes for Solid Oxide Electrochemical Cells

Abstract

Abstract Solid oxide electrochemical cells (SOCs) hold significant promise as a sustainable energy conversion technology due to their high efficiency and minimal environmental impact. However, their development faces critical challenges, particularly in achieving dense ceria/zirconia bilayer electrolytes necessary to fully leverage state‐of‐the‐art cobaltite‐based oxygen electrodes. In this study, a microwave‐assisted volumetric sintering process is successfully employed as a transformative alternative to the conventional, time‐intensive sintering approach, enabling the fabrication of highly dense ceria/zirconia bilayer electrolytes. This innovative method reduced processing time by over 30‐fold compared to convection sintering and achieved a record‐low sintering temperature of 1200 °C. SOCs fabricated with these volumetric heating‐engineered bilayer electrolytes demonstrated outstanding electrochemical performance, delivering a maximum power density of 2.43 W cm −2 at 700 °C in fuel cell mode and a current density of 3.16 A cm −2 at 750 °C in electrolysis mode, alongside excellent long‐term durability. Furthermore, advanced digital twin analysis revealed the critical correlation between microstructural features and electrochemical performance, providing new insights into SOC optimization. This work highlights the potential of microwave‐assisted sintering as a cost‐effective and scalable approach for advancing high‐performance SOC technologies.