One-step synthesis of high performance Sr ₂Fe _1.5Mo _0.5O ₆-Sm _0.2Ce _0.8O _1.9 composite cathode for intermediate-temperature solid oxide fuel cells using a self-combustion technique

A Sr ₂Fe _1.5Mo _0.5O ₆-Sm _0.2Ce _0.8O _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 °C, respectively, in humidified H ₂ (3 vol% H ₂O). Highlights: A one-step self-combustion method is proposed to prepare SFMO-SDC composite. The SFMO-SDC cathode shows porous nanostructure and uniform elements distribution. High performance of SFMO-SDC cathode is presented by low polarization resistance. The maximum power densities reach 2.21, 1.66 and 1.16 W cm ^-2 at 800, 750 and 700 °C.