Characteristics of Sr2Ni1.8Mo0.2O6-δ Anode for Utilization in Methane Fuel Conditions in Solid Oxide Fuel Cells

Abstract

In this study, Sr2Ni1.8Mo0.2O6-δ (SNM) with a double perovskite structure was investigated as an alternative anode for use in the CH4 fuel in solid oxide fuel cells. SNM demonstrates a double perovskite phase over 600°C and marginal crystallization at higher temperatures. The Ni nanoparticles were exsolved from the SNM anode during the fabrication process. As the SNM anode demonstrates poor electrochemical and electro-catalytic properties in the H2 and CH4 fuels, it was modified by applying a samarium-doped ceria (SDC) coating on its surface to improve the cell performance. As a result of this SDC modification, the cell performance improved from 39.4 mW/cm<sup>2</sup> to 117.7 mW/cm<sup>2</sup> in H2 and from 15.9 mW/cm<sup>2</sup> to 66.6 mW/cm<sup>2</sup> in CH4 at 850°C. The mixed ionic and electronic conductive property of the SDC provided electrochemical oxidation sites that are beyond the triple boundary phase sites in the SNM anode. In addition, the carbon deposition on the SDC thin layer was minimized due to the SDC’s excellent oxygen ion conductivity.