Effect of La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ morphology on the performance of composite cathodes

In the present work, one dimensional La_0.8Sr_0.2Co_0.2Fe_0.8O_3-δ (LSCF) nanofibers with the mean diameter of about 100nm prepared by electrospinning were deposited on Gd_0.2Ce_0.8O_1.9 (GDC) electrolyte followed by sintering to form one dimensional LSCF nanofiber cathode. And LSCF/GDC composite cathodes were formed by introducing GDC phases into LSCF nanofiber scaffold using infiltration method. The polarization resistances for the composite cathode with an optimal LSCF/GDC mass ratio of 1/0.56 are 0.27, 0.14 and 0.07Ωcm² at 650, 700 and 750°C, respectively, which are obviously smaller than 2.26, 0.78 and 0.29Ωcm² of pure LSCF nanofiber cathode. And the activation energy is 1.194eV, which is much lower than that of pure LSCF nanofiber cathode (1.684eV). These results demonstrate that the infiltration of GDC into LSCF nanofiber scaffold is an effective approach to achieve high performance cathode for solid oxide fuel cells (SOFCs). In addition, the performance of composite cathode in this work was also compared with that of our previous nanorod structured LSCF/GDC composite cathode.