Performance of H₂S solid oxide fuel cell with yttria-stabilized zirconia conducting membrane

The performance of H₂S solid oxide fuel cell with yttria-stabilized zirconia (YSZ) oxygen ion-conducting membrane was investigated. The binary metal composite MoS₂ anode catalysts (with doping NiS, electrolyte YSZ, Ag powder and starch), the composite NiO cathode catalysts (with admixing electrolyte YSZ, Ag powder and starch), and the membrane electrode assembly (MEA) were prepared. The YSZ and MEA were characterized by using scanning electron microscope (SEM). The performance of several electrode catalysts was compared and the influence of operating temperature on the cell performance was examined. The results demonstrated that the binary metal composite MoS₂/NiS anode catalysts work more stably than Pt and single metal MoS₂ ones in H₂S stream and the performance of composite NiO cathode catalysts is superior to that of Pt. The addition of Ag powder into the electrodes can significantly increase their electrical conductivity. The overpotentials of the composite MoS₂ and NiO catalysts are smaller than that of Pt and the polarization of anode is smaller than that of cathode. With the increase of the cell temperature, the current and power densities are increased due to the elevation of the electrical conductivity of membrane and electrochemical reaction rate of fuel cell, which leads a better cell electrochemical performance. For the single fuel cell with the configuration of “H₂S, (composite MoS₂ anode)/YSZ membrane/(composite NiO cathode), air” operated under 101.13kPa and the temperatures of 750℃, 800℃, 850℃ and 900℃, the maximum currents obtained are 120mA/cm², 240mA/cm², 560mA/cm² and 890mA/cm² and the power density are 30mW/cm², 70mW/cm², 155mW/cm² and 295mW/cm², respectively.