Effect of the cathode structure on the electrochemical performance of anode-supported solid oxide fuel cells

The study elementarily investigated the effect of the cathode structure on the electrochemical performance of anode-supported solid oxide fuel cells. Four single cells were fabricated with different cathode structures, and the total cathode thickness was 15, 55, 85, and 85 μm for cell-A, cell-B, cell-C, and cell-D, respectively. The cell-A, cell-B, and cell-D included only one cathode layer, which was fabricated by ( textLa_0.74 textBi_0.10 textSr_0.16 )textMnO_{3 - d} left( {{text{La}}_{0.74} {text{Bi}}_{0.10} {text{Sr}}_{0.16} } right){text{MnO}}_{{3 - delta }} (LBSM) electrode material. The cathode of the cell-C was composed of a ( textLa_0.74 textBi_0.10 textSr_0.16 )textMnO_{3 - d} - ( textBi_0.7 textEr_0.3 textO_1.5 ) left( {{text{La}}_{0.74} {text{Bi}}_{0.10} {text{Sr}}_{0.16} } right){text{MnO}}_{{3 - delta }} - left( {{text{Bi}}_{0.7} {text{Er}}_{0.3} {text{O}}_{1.5} } right) (LBSM–ESB) cathode functional layer and a LBSM cathode layer. Different cathode structures leaded to dissimilar polarization character for the four cells. At 750°C, the total polarization resistance (R _p) of the cell-A was 1.11, 0.41 and 0.53 Ω cm² at the current of 0, 400, and 800 mA, respectively, and that of the cell-B was 1.10, 0.39, and 0.23 Ω cm² at the current of 0, 400, and 800 mA, respectively. For cell-C and cell-D, their polarization character was similar to that of the cell-B and R _p also decreased with the increase of the current. The maximum power density was 0.81, 1.01, 0.79, and 0.43 W cm⁻² at 750°C for cell-D, cell-C, cell-B, and cell-A, respectively. The results demonstrated that cathode structures evidently influenced the electrochemical performance of anode-supported solid oxide fuel cells.