Correlation Between Microstructure and Performance of GDC-Based Electrodes

Gadolinium doped ceria (GDC) is a promising material for solid oxide cells. GDC is conventionally used as an ionic conductor in composites with electron-conducting metal or perovskite materials. However, recent studies demonstrated that pure GDC fuel electrodes can achieve substantial power density if their microstructure is appropriately designed. Four different types of GDC electrodes are investigated in this study, including conventional Nickel (Ni)-GDC composite, GDC-perovskite composite, GDC deposited with Ni nanoparticles and pure GDC. The test results show a clear correlation between GDC surface area and electrode performance. At the same time, the electrode active thickness depends on the electrode microstructure. It is in the range of 5 µm for the nano-size GDC electrodes. When the GDC electrode is thicker than the active thickness, it results in large ohmic resistance due to the electronic conduction in the outer layer.