High performance of La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_3-Ce_(0.9)Gd_(0.1)O_(1.95) nanoparticulate cathode for intermediate temperature microtubular solid oxide fuel cells

摘要

The perovskite La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_3-Ce_(0.9)Gd_(0.1)O_(1.95) (LSCF-GDC) nanoparticulate cathode was applied for microtubular solid oxide fuel cells operated at intermediate temperatures. For the cell with the cathode sintered at 950 ℃, maximum power densities of 0.26, 0.54 and 0.73 W cm~(-2) were obtained at 550, 600 and 650 ℃, respectively. The ohmic resistance increased for the cathode sintered at 850 ℃, and the polarization resistance increased for the cathode sintered at 1050 ℃. The cathode polarization resistances of ionic conduction process in the LSCF bulk and adsorption/desorption process on the LSCF surface were estimated by the distribution of relaxation times analysis, which were only 0.066 and 0.065 Ω cm~2 at 600 ℃ for the cathode sintered at 950 ℃. The grain size of the cathode was less than 100 nm, which resulted in high performance due to an overall decrease in cathode polarization resistance.