Development of nano-structured electrodes for solid oxide fuel cells

In this thesis, solid oxide fuel cell (SOFC) anode and cathode electrodes are fabricated by infiltrating the relevant catalysts into porous electrolyte skeletons. In this respect, various parameters such as porous layer thickness, number and amount of infiltration repetitions, concentration, test and sintering temperature are optimized. The highest electrochemical performances are obtained at 40 and 30 wt. % Ni and LSM loading, respectively. The cell with only an infiltrated anode exhibits an approximately 2.5-fold improvement in electrochemical performance compared to the reference cell, whereas the cathodeinfiltrated cell demonstrates a 3.2-fold performance enhancement. The optimal sintering temperatures for producing nanostructured Ni and LSM infiltrated membrane electrode assemblies are identified as 800°C and 1000°C, respectively. Based on the electrochemical performance results, the optimal porous layer thickness for infiltration is determined to be 25 µm. The electrochemical performance of the nanostructured solid oxide fuel cell infiltrated with both anode and cathode catalysts is found to be 0.75 W/cm2 at an operating temperature of 800°C. As a result of optimizations, it is proven that high operating and production temperatures, which constitute a major obstacle to the commercialization of solid oxide fuel cells, can be overcome by the infiltration method.