Pore Structure Engineering in Solid Oxide Cell Electrodes: Formation Mechanisms, Characterization Techniques, and Performance Implications

Solid oxide cells (SOCs) have demonstrated efficient energy conversions between power and fuels through reversible operations and will play an important role in renewable energy utilization. The porous structure of electrodes greatly affects cell performance and durability due to multifunctionalities: reaction sites, gas transport, electronic and ionic conduction, as well as mechanical support for supporting electrodes. Therefore, extensive research efforts have been devoted to design and optimize the porous structure of the electrode to achieve enhanced performance and durability, such as a functionally graded porous structure, a finger-like pore structure, etc. Different from the existing literature reviews on SOCs focusing on new materials developments, this paper has reviewed the pore structure engineering, covering pore formation mechanisms, the characterization techniques of pore structure, and the effects of various pore engineering strategies on the performance and durability of SOCs. The direction of future pore structure engineering is discussed.