The electrochemical performance and thermal behavior analysis of SOFC containing thin gadolinium-doped ceria diffusion barrier layer

Abstract

The electrochemical performance and thermal behavior of solid oxide fuel cell (SOFC) stacks are crucial for their stable operation and market deployment. This study focuses on the preparation of gadolinium-doped ceria (GDC) powders using the Solid-liquid method and investigates the impact of precalcination temperatures on the cell's electrochemical performance. A three-dimensional numerical model is developed to analyze the local thermodynamic state of the SOFC using optimal GDC powder, considering electrochemical/chemical reactions, heat and mass transfer, carbon deposition, and mechanical behavior. Results indicate that GDC powders precalcined at 1323 K exhibit suitable sintering activity, leading to stable output power densities of the cell (4 × 4 cm2) at different operating temperatures (1073 K, 1.10 W∙cm−2; 1023 K, 0.87 W∙cm−2; 973 K, 0.56 W∙cm−2). Additionally, the study reveals a uniform temperature gradient distribution in pre-reformed methane-fueled SOFC (highest value: 1477 K∙m−1), albeit with a coking risk in channel unit 4. High temperature/temperature gradient zones are not high-stress zones, with mechanical constraints from stacking contributing more to stress distribution than uneven volumetric thermal expansion.