Ni Modified WC-Based Anode Materials for Direct Methane Solid Oxide Fuel Cells

Abstract

Single cells based on Ni-CeO2-WC-YSZ anodes were investigated as an alternative material for direct methane solid oxide fuel cells. First, a YSZ electrolyte-based cell with porous YSZ as the support for electrode materials on both sides was prepared. Then electrocatalyst materials were incorporated into the porous YSZ: the anode was infiltrated with WC (25 vol.%), Ni (5 wt%) and ceria (5 wt%) precursors; and the cathode with LSM (20 vol.%) precursor. A Ni-CeO2-WC-YSZ symmetrical cell study showed that the Ni modified electrode performed stably with humidified methane at 850°C for a period of 48 hours under open circuit condition; no carbon formation was observed either with in-situ impedance spectroscopy or ex-situ scanning electron microscopy. Furthermore, the fuel cell results revealed that not only does the anode operate steadily with a reasonable performance on methane fuel, but the stability of the carbide phase is well maintained. The cell also successfully survived an oxidation-reduction-recarburization cycle. It was demonstrated that with a proper cell configuration, the structural integrity can be protected. These results suggest that a Ni modified anode is compatible with methane fuel, with reasonable and stable performance.