Microstructural investigation of redox behaviour for nickel based solid oxide fuel cell anodes

Numerical studies are carried out to determine the optimum composition regarding performance and redox tolerance of SOFC anodes, and 3D synthetic microstructure generation was proposed for his purpose. Micro-scale performance analysis of synthetic microstructures generated by Dream.3D software is performed via COMSOL, while micro-scale redox modeling is achieved with LS-DYNA. The highest active TPB density is obtained from an anode with 30 vol. % pore, 35 vol. % Ni and 35 vol. % YSZ, whereas the highest redox tolerance is determined for the anode having 50 vol. % pore, 15 vol. % Ni and 35 vol. % YSZ. To examine the anode microstructure and analyze the effects of the redox process on TPB experimentally, the produced cells are subjected to 30 redox cycles and the cell performance tests are carried out after each redox cycle. 2D images of the anode samples after some selected redox cycles are obtained by low voltage FE-SEM for microstructural analyses. According to the volumetric ratio and particle size/distribution data obtained after image processing, 3D microstructures are generated synthetically and the resultant TPBs are computed. In this way, the effect of the redox process on the microstructural performance is investigated aiming to observe the relationship between the cell performance and TPB density experimentally.