Multi-objective optimization of fuel electrode microstructure for cost-effective and high-performance solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) offer significant potential for efficient hydrogen production; however, their performance and cost are highly dependent on the microstructure of the fuel functional layer (FFL). This study focuses on optimizing both the material composition and microstructural design of the FFL, which comprises nickel (Ni) and yttria-stabilized zirconia (YSZ). The particle sizes of Ni and YSZ influence the active surface area for electrochemical reactions and ohmic resistance, while FFL porosity affects gas transport and electrical conductivity. These parameters not only impact overall SOEC performance but also contribute substantially to raw material costs, as smaller particle sizes typically require more complex and expensive fabrication methods. To address this challenge, a multi-objective optimization framework is employed to investigate the trade-offs between performance and cost, with a focus on Ni and YSZ particle sizes and FFL porosity. The Pareto front analysis delineates a continuum of design strategies, spanning high-performance configurations associated with elevated costs to more cost-effective but suboptimal alternatives. Specifically, the single-objective optimization (SOO) framework prioritizes the minimization of cell voltage, often at the expense of increased fabrication or material costs. A comprehensive voltage decomposition further elucidates the influence of microstructural parameters on activation and ohmic overpotentials, indicating that SOO-driven designs effectively suppress these losses through reduced particle sizes and decreased porosity. Our analysis identifies promising microstructural configurations that enhance SOEC performance relative to a baseline case while simultaneously reducing raw material costs. This strategy provides a pathway toward cost-effective and high-efficiency SOEC technologies for sustainable hydrogen production.