No abstract

No abstract

No abstract

Key words nano-crystalline powders, strontium-doped lanthanum manganite, polymerizing agent.Strontium-doped lanthanum manganite (La 1-x Sr x MnO 3 or LSM) is the material most widely used on solid oxide fuel cells cathode. In this work, nano-scale La 0.8 Sr 0.2 MnO 3 powders have been synthesized by polymeric precursor-based methods using different polymerizing agents with the aim of evaluating the influence of this change in the final powder. The powders calcined at 700 °C for 2 h have been characterized by X-ray diffraction (XRD), scanning electron microscopy (FE-SEM) and Fourier transform infrared spectroscopy (FTIR) in order to investigate the quality of both synthesis routes. It is shown that the crystal structure and morphology of the particles are significantly dependent on the preparation conditions. Single phase and La 0.8 Sr 0.2 MnO 3 nano-crystalline particles less than 30 nm were obtained using ethylene glycol as polymerizing agent. FTIR results have been indicated that only the powder obtained using gelatin presented small traces of hydroxyl groups on its surface.

This paper presents an overview of recent advances in the synthesis and preparation of solid oxide fuel cells (SOFCs) functional ceramic materials, focusing on low-/intermediary-temperature SOFCs. Novel synthesis processes for oxygen ion-conducting and mixed electronic and ionic conductors, fundamental to reduce the operating temperature of SOFCs were studied. Ni-Ce0.9Gd0.1O1.95 (Ni-CGO) anodes were successfully synthesized by the so called “one step synthesis”. La0.5Sr0.5Co0.8Fe0.2O3 (LSCF), Ce0.8Sm0.2O1.9 (SDC) and their mixture were produced as a cobaltite-based composite cathode by mixing powders synthesized by microwave-assisted combustion and the modified polymeric precursor method, respectively. Preliminary electrochemical activity tests with the synthesized electrodes were performed in electrolyte-supported SOFCs using commercially available 200 µm thick yttria stabilized zirconia (8YSZ) as electrolyte. The maximum power density of 52 mW/cm2 was reached at 850 °C. This result can be further improved replacing thick YSZ electrolytes by doped-ceria thin films, aiming at operation temperatures of 500–800 °C and power densities as high as 800 mW/cm2. The assembling of anode-supported cells with the configuration Ni-CGO/CGO (10 µm thickness)/LSCF-SDC are for applications in 2 kW stacks are currently under way.