Structurally Stable Perovskite Cathode with Extended Lifetime for Protonic Ceramic Fuel Cells

In recent years, the cathode materials of protonic ceramic fuel cells (PCFCs) have been rapidly developed, and the catalytic activity of the cathode has been greatly improved. However, the segregation of Ba and Sr elements in the cathode significantly affects the stability of the cathode. To address this challenge, the Pr_0.8Ba_0.2Fe_0.8Co_0.2O_3−δ (PBFC) perovskite with its Ca-doped derivative Pr_0.6Ba_0.2Ca_0.2Fe_0.8Co_0.2O_3−δ (PBCFC) of high crystal symmetry is developed and investigated as a cathode for PCFCs. The study confirms the significant contribution of Ca doping in suppressing Ba segregation and improving the stability of the cathode. The cell with the PBCFC cathode can maintain excellent stable electrochemical performance over 1000 h at 650 °C, without any performance degradation throughout the test period. Further, the introduction of Ca doping can reduce the extent of lattice distortion and improve the degree of symmetry, thereby improving the catalytic activity of the electrode. The single cell with the PBCFC cathode can achieve a peak power density of 1.26 W cm^–2 at 700 °C. This work confirms the crucial function of Ca doping in the stabilization of the material and illustrates the potential of PBCFC as the cathode for PCFCs.