A solid oxide fuel cell with molten tin anode for electricity generation and methane reforming

Abstract A methane-fuelled solid oxide fuel cell (SOFC) with molten tin anode (Sn(l)-SOFC) is designed, fabricated, demonstrated and characterized. This SOFC design incorporates molten tin contained in an alumina crucible as anode for the solution of oxygen atoms transported to an anode | Yttria stabilized Zirconia (YSZ) electrolyte interface and provides bubble | molten tin interfaces for the reaction of methane with oxygen atoms during cell operation. A peak power density of ca. 100 W m−2 at a current density of 222 A m−2 and potential difference of 0.45 V is obtained for this methane-fuelled Sn(l)-SOFC at 850 °C. The ohmic and non-ohmic impedance are ca. 16.72 and 3.36 Ω cm2, respectively. Ohmic potential losses control the reactor performance, with about ca. 59% of those arising from the inherent difficulty in achieving a low resistance contact at the silver wire (silver wool) current collector | Lanthanum strontium manganite cathode interface. Improved performance is achievable by eliminating contact resistance, utilising a molten metal/alloy with greater activity for methane oxidation and operating the cell at higher temperatures. The reaction of methane at bubble | molten tin interface involves its coupling in addition to oxidation, to produce steam, carbon dioxide, hydrogen, ethane and ethylene.