Analysis of performance of molten carbonate fuel cell VI. Analysis of Nernst loss on current interrupt wave

Estimation of the overpotentials due to internal resistance, polarization by electrode reaction and Nernst Loss in Molten Carbonate Fuel Cell (MCFC) was mainly carried out by analyzing the variation of equilibrium output voltage fixed a current density under several gas conditions till now. On the other hand, transient response analysis methods such as AC Impedance and Current Interrupt are being applied to the estimation in bench-scale cell level for the last few years. In connection with the Current Interrupt measurement, the potential relaxation after current interruption is observed the internal resistance, the reaction polarization and Nernst Loss in order. The relaxation due to Nernst Loss is continued during 10 sec range. The long time relaxation can not be explained from the values of gas velocity (10 cm/sec range) and gas phase diffusion (1 cm(2)/sec range) in a bench-scale cell (10 x 10 cm area). Therefore, we grasped the long time relaxation as the liquid phase diffusion process in electrolyte kept in porous electrode and estimated the apparent diffusion coefficients and diffusion layer in molten carbonate mixtures.