Protonic Ceramic Electrolysis Cells for Green Energy Conversion: Fundamental Characteristics, Key Components, and Application Potential

ABSTRACT Protonic ceramic electrolysis cells (PCECs) have emerged as a transformative technology for low‐cost, large‐scale green hydrogen production, owing to their intrinsic high energy conversion efficiency and unique advantages of mid‐temperature operation. However, systematic discussion is still lacking regarding the unique characteristics of PCEC systems and the specific implications of these characteristics for material design and operational condition optimization. This review provides a comprehensive and critical assessment of milestone innovative achievements across the entire development chain of PCECs, from fundamental laboratory research to large‐scale energy applications. Specifically, it highlights the critical roles of compositional regulation, structural design, and fabrication process optimization in breaking through the core technical bottlenecks, systematically analyzes the physicochemical stability, interface bonding strength, and electrochemical–thermal coupling behavior of electrolyte and electrode components under practical operating conditions, thoroughly explores the engineering application potential from single‐cell scale‐up, stack design to system integration, and finally discusses the key challenges and future development prospects in the industrial scaling‐up process.