DEPENDENCE OF ENTROPY CHANGE OF SINGLE ELECTRODES ON PARTIAL-PRESSURE IN SOLID OXIDE FUEL-CELLS

The dependence on hydrogen partial pressure of the entropy change of the hydrogen electrode reaction on platinum electrodes on yttria-stabilized zirconia was estimated from measurements of the Seebeck coefficient of the yttria-stabilized zirconia. The entropy change of the oxygen reaction also was estimated by Seebeck coefficient measurements. The total entropy change of the reaction in a solid oxide fuel cell was calculated from the thermodynamic data. An empirical equation for the dependence of the entropy change of the hydrogen electrode reaction on hydrogen partial pressure was obtained from the observed entropy change of the oxygen electrode and the total entropy change. The observed dependence of the entropy change of the hydrogen electrode reaction on hydrogen partial pressure was in good agreement with the empirical equation.