Effect Of H_2S On Ni-YSZ SOFC Anodes: A Combined In Situ Raman Spectroscopy - Impedance Spectroscopy Study

摘要

A combined Raman spectroscopy-impedance spectroscopy study of a Ni-YSZ anode of a SOFC cell has ben performed at 500°C in open circuit potential and at 500 mV polarization. The effects of adding 200 ppm H_2S to the Ar-3 %H_2-3% H_2O feeding gas have been observed. In OCP condition, the Raman spectrum of Ni_3S_2 is observed only 5.5 hours after the introduction of H_2S, while the electrode impedance was reduced. The impedance grew only when the Raman signal of Ni_3S_2 saturated. At 500 mV polarization, Raman spectra of Ni_3S_2 were also observed together with a huge increase of the electrode impedance. For temperatures higher than 500°C, Ni_3S_2 shows no Raman spectrum, but high temperature optical spectroscopy shows that the growth of the Ni_3S_2 crystals can be observed at 715°C.