Electrochemical behaviors of Y-doped La0.7Sr0.3CrO3−δ anode in sulfur-containing fuel SOFC

• Effect of Y as dopant on electro-catalytic activity for LSCY was investigated.
• Electro-catalytic activity of LSCY still needs improvements.
• EIS indicates polarization loss for LSCY dominates in the total resistance loss.
• A hypothesis about choice of doping cation is proposed.

Fuel gas containing sulfur to feed solid oxide fuel cell is a challenge for extending the application of SOFC. Yttrium doped into LaxSr1−xCrO3 as potential anode tolerant to H2S was investigated by XRD, XPS and electrochemical impedance spectra (EIS). Good sinter characteristic for (La,Y)0.7Sr0.3CrO3−δ (LYSC) observed by SEM contributes to the low ohmic loss (high conductivity) in SOFC fueled by H2(3%)–H2S(1%). Maximum power density of 20 mW/cm2 and open circuit voltage of 0.95 V for SOFC with LYSC can be obtained at 700 °C. The results by EIS indicate charge transfer loss in polarization resistance dominates in the total resistance, especially lower than 650 °C. Compared to ohmic loss, polarization resistance in LYSC is still the main cause to hinder the improvement of SOFC performance. Thus, LYSC with doped non-variant valence Y maintains good sulfur tolerance determined by XPS without improved electro-catalytic activity as EIS suggest.

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