Investigation of Current Leakage of Micro-tubular SOFCs with a Ceria Membrane for Low-intermediate Temperature Power-generation Applications

In this work, current leakage of the micro-tubular cells with a 10-mu m Ce0.9Gd0.1O1.95 (GDQ electrolyte based on cathode- and anode-supported configurations was investigated at 500 and 550 degrees C. It was found that the open circuit voltage (V-OC) of the GDC membrane cell greatly corresponds to the cell structure, particularly influenced by the electrode polarization. Calculations derived from the experimental results showed that the leak current through the GDC electrolyte gradually vanished as the external current increased to certain degree, which accordingly related to the polarizations, due to the cell structures. The anode-supported cell can be capable of generating a high power density with a reasonable maximum-efficiency. On the other hand, not only V-OC but also cell output and efficiency were significantly lowered for the cathode-supported cell. It suggests that an appropriate cell structure is necessary to make the doped ceria a promising electrolyte for low-intermediate temperature power-generation applications.