The investigation of active Ni/YSZ interlayer for Cu-based direct-methane solid oxide fuel cells

In this study, dense YSZ (d_YSZ)–Ni/YSZ–porous YSZ (p_YSZ) double-layer anode structures were prepared by the tape casting–lamination–co-sintering (TLC) method to improve the stability of the cells due to the cracking reaction of methane. Cu was infiltrated into all cells as an electronic conductive material. The effect of CeO2 and SDC (samarium-doped ceria) loadings were also investigated. Stable operation was obtained by using a Ni-interlayered Cu-based anode structure for dry methane fuel at 800 °C for 72 h. No carbonization was observed after the addition of Cu to the cell. An interesting finding was that a highly loaded secondary material (CeO2 and SDC) leads to a regional break of the electronic conduction network, which decreases the number of active TPB regions. Therefore, carbonization occurred inside the cell in the Ni-containing interlayer zone. At the end of 72 h of cell operation, carbonization was observed inside the Ni-containing and Ni-free regions in the SDC-containing cell. In addition to conducting cell tests, the behavior of powder SDC was studied under a dry methane environment by temperature-programmed surface reaction (TPR) and temperature-programmed oxidation (TPO) analysis.