Highly redox-resistant solid oxide fuel cell anode materials based on La-doped SrTiO₃ by catalyst impregnation strategy

An anode backbone using 40 wt% (ZrO₂)_0.89(Sc₂O₃)_0.1(CeO₂)_0.01 (SSZ)-Sr_0.9La_0.1TiO₃ (SLT) cermet was prepared for SSZ electrolyte-supported SOFC single cells. 15 mgcm^-2 Ce_0.9Gd_0.1O₂ (GDC) was impregnated to totally cover the SSZ-SLT anode backbone surface acting as a catalyst, and the cell voltage achieved 0.865 V at 200 mAcm^-2 using (La_0.75Sr_0.25)_0.98MnO₃ (LSM)-SSZ cathode in 3%-humidified hydrogen fuel at 800 °C. Cell performance was substantially improved from 0.865 V to >0.97 V when 0.03 mgcm^-2 Pd or Ni was further incorporated as a secondary catalyst into the anode layer. 50 redox cycles were performed to investigate redox stability of this high performance anode. It was found that even after the 50 redox cycle long-term degradation test, cell voltage at 200 mAcm^-2 was retained around 0.94 V, higher than the cell performance using the conventional Ni-SSZ cermet anode. The catalytically-active reaction sites at ceria-Pd or ceria-Ni may account for the excellent performance, and the extremely low metal catalyst concentration prevent serious metal aggregation in achieving excellent redox stability.