Toward Efficient and Reliable Chemical Upgrading Using Solid Oxide Electrochemical Reactors, Mechanisms, Challenges, and Design Principles

ABSTRACT Solid oxide electrochemical reactors (SOERs) offer a compelling pathway for upgrading feedstocks into value‐added chemicals using renewable electricity, in which electrode reaction kinetics can be precisely regulated by external electricity to surpass reaction thermodynamic limitations. However, the practical deployment of SOERs remains constrained by low product yields and instability. Existing studies have largely focused on isolated material innovations and have reported scattered performance data under seemingly similar conditions, lacking an integrated perspective that bridges material design, device engineering, and electrochemical coupling. Here, we present a comprehensive review of both protonic and oxygen‐ion‐conducting SOERs for chemical synthesis. We first outline reaction mechanisms and cell configurations across key reactions, including cathodic CO 2 upgrading, anodic methane coupling, alkane‐to‐olefin conversion, and their hybrid pathways, establishing a foundation for next‐generation material development. We then summarize the critical factors governing conversion efficiency, product selectivity, and operation stability from both electrochemical and catalytic perspectives. Subsequently, recent advances in electrode development for enhancing electrochemical performance and product yields are summarized and compared. Finally, future opportunities and research directions are outlined to accelerate the commercial translation of SOER technologies. This review provides a framework for understanding complex SOER‐driven chemical upgrading and offers guidance for its development.