GAS CONVERSION IMPEDANCE: SOFC ANODES IN H_2/H_2O ATMOSPHERES

摘要

Impedance spectra are obtained in H_2/H_2O on Ni/YSZ cermet anodes. These impedance spectra are fitted to the equivalent circuit LR(RQ)_1(RQ)_2(RC)_3. The subcircuit (RC)_3 is found to have a capacitance in the order of 0.1-1.1F only when the current-bearing electrodes are in separate atmospheres. This impedance is derived analytically and shown to represent the change in composition of a gas volume above the anode. This impedance has no direct relations to anode composition or electrochemical performance, but will inevitably contribute to the measured polarisation resistance.