The Comparisons of Electrical Performance and Impedance Spectrum for Two Commercial Cells

Abstract

A solid oxide fuel cell (SOFC), which is a kind of fuel cell (FC) converting chemical energy into electricity directly without mechanical parts, has potential for the clean and efficient power generation from a wide variety of fuels ranging from hydrocarbons to renewables and coal-derived fuels. The Institute of Nuclear Energy Research has been committed to developing the SOFC technology since 2003 and the cell test is one of the working items in the project. Cells are the most important components in an SOFC stack, which are responsible for the electrical output functioning, as the heart in the human body, to the stack. Before stacking, it is essential to examine and evaluate the electrical performance of the cells that could be used in our stacks. There are two commercial cells tested in this paper. For both cell A, an anode supported cell, and cell B, an electrolyte supported cell, the cells with a lower open circuit voltage at a higher operating temperature are contributed by the Nernst equation. The I-V curve for a lower operating temperature with a steeper slope at the low current zone is credited to the increase of activation polarization from the triple phase boundary. Comparison between cell A and cell B, the electrical performance of cell A is better than that of cell B due to cell A possessing a lower total resistance at the same operating temperature.