Solid oxide fuel cell using a H2 fuel/CO2 oxidant gas system

This paper reports the performance of a solid oxide fuel cell with yttria-stabilized zirconia (YSZ) electrolyte, Ni–YSZ anode and (La0.8Sr0.2)0.95MnO3 (LSM) cathode or RuO2–YSZ cathode using air oxidant or a CO2 oxidant and a H2 fuel with 3% H2O at 600–800°C. The power density was higher for air oxidant than for a CO2 oxidant. The measured power density was associated with the reduction of CO2 gas to solid carbon for the RuO2–YSZ cathode. In the cell with the LSM cathode, a CO2 oxidant was reduced to the mixed state of CO molecules and solid carbon. The reactivity of O2 or CO2 molecules in their mixed oxidant gas system for the YSZ cell with the LSM cathode changed drastically at 50–70 vol % CO2 in the O2–N2–CO2 gas system. It is possible to produce an electric power and to reduce CO2 gas into solid carbon at the same time during the operation of a solid oxide fuel cells using a CO2 oxidant.