Chemical degradation behavior of SOFC anode due to trace impurities contained in a coal derived syngas

摘要

In an effort to explore the feasibility of coal-syngas use as a fuel for solid oxide fuel cell (SOFC), we need to clarify the anode degradation behavior due to the interaction between trace chemical impurities and SOFC anode and electrolyte. We conducted the power generation tests using electrolyte-supported button cells with Ni-YSZ anode fueled by the simulated coal syngas with/without doping of selected gaseous/condensable contaminants. Doping of metal vapors volatilized from coal ash to fuel gas resulted in the formation of eutectic melting or agglomeration of Ni over the anode layer. When Na vapor was injected to the anode chamber, solid state Na-Si deposit was observed on the anode surface which would cause the increase in resistance for fuel supply. No significant negative influence was seen in the variation of current density with time as well as AC impedance in the case of injection of 2ppm halide components. (HCl & HF).