Study On Preparation Of Hydrocarbon Solid Oxide Fuel Cell Anode And Its Electrochemical Performance

The major barrier which limits the application of the hydrogen-fueled solid oxide fuel cells（SOFCs） is the high cost of hydrogen. Hydrocarbons are much cheaper but lead serious carbon deposition on nickel-based cermet SOFC anodes. Two novel anodes Ni_1-xFe_xO_1+δ-SSZ and La_0.6Sr_0.4Cr_1-xFe_xO_3-δ are synthesized, with their properties evaluated to optimize the performance of single cells.Ni_1-xFe_xO_1+δ are synthesized by glycine nitrate combustion method. The reduced products of Ni_1-xFe_xO_1+δ remain Ni-Fe alloys with cubic structure when the Fe doping content x is less than 50%. The results of EIS and discharging test show the performance of single cells decrease gradually with the Fe content increasing. Good stability of the single cell with Ni_0.75Fe_0.25O_1+δ-SSZ anode is demonstrated under a constant current density operating on both methane and carbon monoxide. Ni_0.75Fe_0.25O_1+δ-SSZ-CeO₂ anodes are prepared by impregnation method and the optimum impregnation amount of CeO₂ is 20 wt%. The maximum power densities are 235.46 and 323.71 mW·cm-2 operating on methane and carbon monoxide respectively.Perovskite La_0.6Sr_0.4Cr_1-xFe_xO_3-δ（LSCrFe） anodes are synthesized by solid state reaction method. The stability of LSCrFe in reducing atmosphere are excellent when the Fe content x is between 0.2⁰.4. The maximum conductivity of 1.49 S·cm-1 is achieved at 800℃ when the Fe content x is 0.4. LSCrFe40 exhibits the minimum polarization resistance（Rp） of 1.358 Ω·cm2 at 850℃. The single cell with LSCr Fe40 anode shows the maximum power density of 122.65 mW·cm-2 at 850℃ in hydrogen, whereas it performs terribly in both methane and carbon monoxide. The LSCrFe-SDC anodes are first prepared by physical mixing. The Rp reaches the minimum of 0.759 Ω·cm2 at 850℃ with 30 wt% SDC. And the maximum power densities are 151.24（850℃）, 90.93（950℃） and 132.05 mW·cm-2（850℃） operating on hydrogen, methane and carbon monoxide, respectively. Impregnation method has been used to optimize the electrochemical performance of LSCr Fe-SDC anode and the maximum power densities are 251.35（850℃）, 158.37（950℃） and 223.33 mW·cm-2（850℃） in hydrogen, methane and carbon monoxide, respectively.