A2MgMoO6 (A = Sr,Ba) for use as sulfur tolerant anodes

The objective of this effort is to explore the substitution of the A-site in an A2MgMoO6 perovskite with Sr and Ba to improve the sulfur tolerance of solid oxide fuel cells (SOFCs). Perovskites have demonstrated superior sulfur tolerance but lack the high conductivity and catalytic activity of Ni/YSZ cermets. Sr2MgMoO6, a double perovskite, has been suggested as a material of interest because of its relatively high conductivity and catalytic potential. This study summarizes the synthesis of A2MgMoO6 (A = Sr,Ba) through sol–gel methods. The conductivity of the two samples was measured from thin pressed disks. Electrochemical performance of the specimens was performed by pasting the material onto an LSGM disk and stability was measured in sulfurous H2 (140 ppm H2S). Both SMMO and BMMO demonstrated superior stability when exposed to 140 ppm of H2S as compared to Ni/YSZ, but did exhibit performance degradations due to sulfur accumulation in the buffer layer.

▶ Sr2MgMoO6 and Ba2MgMoO6 were generated as sulfur tolerant anodes. ▶ Sr2MgMoO6 and Ba2MgMoO6 showed better sulfur tolerance than Ni/YSZ. ▶ Sr2MgMoO6 demonstrated stability in all environments for an anode material. ▶ Ba2MgMoO6 formed impurities when fired in air 1300 °C and in 100 ppm H2S at 800 °C. ▶ EDAX experiments showed evidence of sulfur accumulation in the LDC buffer layer.