Direct use of coke in a solid oxide fuel cell

Abstract

Direct carbon solid oxide fuel cell (DC-SOFC) is a potential technology for generating electricity from solid carbon fuel with high conversion efficiency and low pollution. In this study, the use of industrial coke as a fuel for a direct carbon solid oxide fuel cell (DC-SOFC) was investigated. Tubular yttrium-stabilized zirconia (YSZ) electrolyte-supported solid oxide fuel cells (SOFCs) with a cermet of silver and gadolinium-doped ceria (Ag-GDC) as electrode material were fabricated. Raman spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy were applied to characterize the investigated coke fuels. It was observed that the coke fuel was micron-sized particles with many structural defects, which favored the Boudouard reaction occurring in a DC-SOFC. A peak power density of 149 mW/cm2 at 850°C was observed for pure coke fuel, and it improved to 217 mW/cm2 when a Fe-based catalyst was added to enhance the Boudouard reaction. The degradation performance of the DC-SOFC during a discharging test was analyzed according to the electrochemical characterization and emitted gas measurements. The performed test supported the feasibility of using coke as fuel in an all-solid-state DC-SOFC to generate electricity.