Preparation and characterization of microemulsion-derived nickel-YSZ SOFC anodes.

摘要

Solid oxide fuel cells (SOFCs) are high efficiency energy conversion devices that operate at temperatures between 600°C to 1000°C. Ni-based anode with 8 mol % yittria stabilized zirconia (YSZ) electrolytes and lanthanum strontium manganite (LSM) cathodes are employed by all SOFC vendors. The commercialization of SOFCs is, nonetheless, hindered by several factors including the performance of the anode. In this research, the performance of SOFC anodes based on microemulsion-prepared nickel, yttrium and zirconium hydroxide nanoparticles are evaluated. Microemulsion-prepared nanoparticles are characterized by very small sizes (1-10 nm) and very homogenous composition as confirmed by X-Ray diffraction and transmission electron microscopy. Anodes were prepared using two different approaches. In one approach, nickel and yttrium and zirconium hydroxides were prepared separately in different microemulsions, and after drying and heat treatment the powders were mixed to form the electrodes. In a second approach, mixed hydroxides were prepared in a single microemulsion system, and electrodes were prepared from this homogeneously mixed powder after drying and heating.;Three-electrode half-cell arrangement was used to perform cyclic voltametry and impedance spectroscopy to study the performance of microemlsion-derived anodes with H2 as a fuel. The results showed that the performances of microemulsion-derived anodes are almost similar to those of sol gel-derived ones. However, their performance is lower than commercially available, NiO and YSZ-derived anodes. It is believed that cracks developed upon reduction of microemulsion-derived anodes under H2 atmosphere at 800°C, as confirmed by scanning electron microscopy. These cracks contributed to lower contact between Ni-Ni and YSZ-YSZ particles and resulted in lower performance.