Current distribution analysis of a microtubular solid oxide fuel cell with surface temperature measurements

Current distribution of a practical solid oxide fuel cell (SOFC) has been analyzed from a thermal analysis combined with surface temperature measurements. Electrochemical impedance spectroscopy with two-electrode set-up is employed on an anode-supported microtubular SOFC. This cell is an intermediate temperature SOFC composed of Ni/(ZrO ₂) _0.9(Y ₂O ₃) _0.1 cermet anode, La _0.8Sr _0.2Ga _0.8Mg _0.2O _2.8 electrolyte, and (La _0.6SrO ₄)(Co _0.2Fe _0.8)O ₃ cathode. The impedance spectra give the resistances at the anode and cathode and the cell ohmic resistance. By numerically integrating these resistances, overpotentials are evaluated. The overpotentials and the single electrode (electrochemical) Peltier heats at the anode and cathode provide individual heat production rates. Since the energy balance equations incorporating these heat production rates determined by current yield the surface temperatures of the cell, local current densities are obtained so that the calculated and measured temperatures by thermocouples at several positions in the anode and cathode surfaces coincide.