Scoping Review of Potentials to Optimize Planar Solid Oxide Cell Designs for Use in Fuel Cell and Electrolysis Applications

This scoping review evaluates the literature on options for planar solid oxide cell (SOC) performance optimization, with a focus on applied fabrication methods and design enhancements. Literature identification, selection, and charting followed PRISMA-ScR guidelines to ensure transparency, reproducibility, and comprehensive coverage, while also enabling the identification of research gaps beyond the scope of narrative reviews. We analyze the influence of fabrication methods on cell and component characteristics and evaluate optimization approaches identified in the literature. Subsequent discussion explores how design innovations intersect with fabrication choices. The surveyed literature reveals a broad spectrum of manufacturing methods, including conventional processes, thin-film deposition, infiltration, and additive manufacturing. Our critical assessment of scalability revealed that reduction in operating temperature, improving robustness, and electrochemical performance are the main optimization objectives for SOC designs. Regarding production cost, production scale-up, and process control, inkjet, electrophoretic deposition, and solution aerosol thermolysis appeared to be promising manufacturing methods for design enhancements. By combining the PRISMA-ScR evidence map with a synthesis focused on scalability and process control, this review provides practical insights and a strong foundation for future SOC research and scale-up, also for evolving the field of proton-conducting cells.