One-step synthesis of high performance Sr_2Fe_(1.5)Mo_(0.5)O_6-Sm_(0.2)Ce_(0.8)O_(1.9) composite cathode for intermediate-temperature solid oxide fuel cells using a self-combustion technique

摘要

A Sr_2Fe_(1.5)Mo_(0.5)O_6-Sm_(0.2)Ce_(0.8)O_(1.9) (SFMO-SDC) nanocomposite material has been prepared by the self-combustion method. The phase structure and morphology of the material have been characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). These results show the coexistence of perovskite and fluorite structures within the porous microstructure which are uniformly distributed throughout the prepared samples. The electrochemical performance of the material has been investigated by electrochemical impedance spectroscopy (EIS) measurements. Using an SDC interlayer SFMO-SDC composite cathode is prepared and applied onto a standard YSZ (8% Y_2O_3-stabilized ZrO_2) electrolyte. A low polarization resistance of the prepared sample is obtained and remarkable performance of the SFMO-SDC based IT-SOFCs is achieved. It is demonstrated that the SFMO -SDC/SDC/YSZ/NiO-YSZ fuel cell reached power densities of 2.21,1.66,1.16 and 0.71 W cm~(-2) at 800, 750, 700 and 650 ℃, respectively, in humidified H_2 (3 vol% H_2O).