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

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.