Preliminary Studies about Synthesis and Electrical Properties of Ruthenium Doped Lanthanum Strontium Titanate as a Potential Anode of Solid Oxide Fuel Cells

The lanthanum strontium titanate (LST) is one of the most representative alternative anode materials. Although it shows low catalytic properties, the disadvantage could be improved by doping of ruthenium which is widely used as catalyst under steam reforming reaction or oxidation reaction. The ruthenium doped lanthanum strontium titanates (LSTRs) powders were synthesized by complex EDTA-citrate method showing well crystallinity. Additionally, the prepared samples were evaluated through various experimental tests. For example, the stability in the reducing atmosphere and chemical compatibility with YSZ electrolyte such as reactivity test in high temperature were confirmed by XRD (X-ray diffraction). And electrical conductivity in wet H-2 atmosphere at 900 degrees C is about 350.6 S/cm, 342.4 S/cm and 179.1 S/cm with sintered bar of LST, LSTR0.02 and LSTR0.05, respectively.open1111Nsciescopu

Performance of an Anode Supported Solid Oxide Fuel Cell with Indirect Internal Reforming

The conversion of fuel into hydrogen-rich gas is necessary for fuel cells. This can be achieved either indirectly in fuel processing systems, in which the hydrocarbon feed is converted in an external catalytic steam reformer, or directly in the fuel cell. In this paper, the unit module of solid oxide fuel cell was assembled by one reformer and four cells. The reformer was fabricated by extruded dummy cell and combined with two cells on each side respectively. The reforming catalyst was coated on internal channel of the dummy cell. The unit module has successfully tested with wet CH4 as fuel and air as oxidant and its maximum power density exceeded 150mW/cm(2) at 750 degrees C.open110Nsciescopu

Design and Fabrication of Electrolyte-Supported Tubular SOFC Combined with Supercritical Water Oxidation on Biomass Gas

Solid oxide fuel cells (SOFCs) are relatively simple and environmental friendly devices for the production of electricity from hydrocarbons. The use of a high pressure supercritical water (SCW) reactor containing a SOFC has the potential for using a multitude of logistical liquid fuels that would otherwise not be possible in a regular SOFC system. A SOFC-SCW system was designed to allow the anode to be exposed to the pressure and chemical milieu of the supercritical water oxidation reactor. The effects of the amount of water/fuel and oxygen fed into the reactor under SCW conditions at 400 degrees C were studied. The effects on electrochemical performance as well as preliminary results on a number of feed stocks, for example pectin, are also described.open1111Nsciescopu

Application of silver in microtubular solid oxide fuel cells

In this paper, the behaviour of silver as cathode conductive material, interconnect wire, and sealing for anode lead connection for microtubular solid oxide fuel cells (µSOFC) is reported. The changes in silver morphology are examined by scanning electron microscopy on cells that had been operated under reformed methane. It is found that using silver in an solid oxide fuel cell (SOFC) stack can improve the cell performance. However, it is also concluded that silver may be responsible for cell degradation. This report brings together and explains all the known problems with application of silver for SOFCs. The results show that silver is unstable in interconnect and in cathode environments. It is found that the process of cell passivation/activation promotes silver migration. The difference in thermal expansion of silver and sealant results in damage to the glass. It is concluded that when silver is exposed to a dual atmosphere condition, high levels of porosity formation is seen in the dense silver interconnect. The relevance of application of silver in SOFC stacks is discussed

A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3

Oxide ion conductors find important technical applications in electrochemical devices such as solid-oxide fuel cells (SOFCs), oxygen separation membranes and sensors1, 2, 3, 4, 5, 6, 7, 8, 9. Na0.5Bi0.5TiO3 (NBT) is a well-known lead-free piezoelectric material; however, it is often reported to possess high leakage conductivity that is problematic for its piezo- and ferroelectric applications10, 11, 12, 13, 14, 15. Here we report this high leakage to be oxide ion conduction due to Bi-deficiency and oxygen vacancies induced during materials processing. Mg-doping on the Ti-site increases the ionic conductivity to ~0.01 S cm−1 at 600 °C, improves the electrolyte stability in reducing atmospheres and lowers the sintering temperature. This study not only demonstrates how to adjust the nominal NBT composition for dielectric-based applications, but also, more importantly, gives NBT-based materials an unexpected role as a completely new family of oxide ion conductors with potential applications in intermediate-temperature SOFCs and opens up a new direction to design oxide ion conductors in perovskite oxides

A new dielectric ceramic based on Pb(TixZr1-x)O-3

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The Catalytic Oxidation of Methanol over La1-x(Sr,Ca)xMO3-delta (M= Co, Cr, Fe or Mn) Perovskite Materials

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Mechanical Properties of Strontium Doped Lanthanum Manganite

Solid oxide fuel cells that incorporate stabilized-zirconia electrolytes commonly use the transition-metal oxide perovskite La0.875Sr0.125MnO3+delta as the cathode. While in operation, the cathode can be subjected to significant stresses, because of thermal expansion mismatch between mating components. The mechanical behavior of La0.875Sr0.125MnO3+delta has been studied using three-point bend strength measurements at ambient, 400 degrees C, 800 degrees C and 1000 degrees C. The results show that phase transformations have an important role in the mechanical-strength behavior. The results also indicate some unique strengthening effects that are associated with the evolution of the unit cell with temperature and the increasing symmetry of the crystal lattice.X1126sciescopu