Assessment of performances of Ni-Cu-LSGM as anode materials for intermediate-temperature LaGaO3-based solid oxide fuel cells

The performances of Ni-Cu-LSGM as anode materials for intermediate-temperature LaGaO3-based solid oxide fuel cells were assessed. The phase composition of samples before and after reduction was characterized by X-ray diffractornetry. The electrical properties of samples were measured using impedance spectroscopy in air and hydrogen atmospheres. The thermal expansion coefficients (TECs) of samples before and after reduction were measured using a dilatometer. The electrochemical characteristics of cell with designed anodic materials were analyzed to evaluate the feasibility for anodic application. The results show that no significant reaction between NiO and LSGM is detected for samples sintered at 1000 degrees C for 10 h, but when the samples were sintered at 1050 degrees C for 10 h, the impurity phase LaNiO3 was detected. For samples after reduction, the impurity phase content tends to increase with increasing Ni content. Adding of Cu can effectively reduce the reaction between Ni and LSGM. The electronic conduction characteristics have been displayed for NiO-CuO-LSGM after reduction. The TECs of Ni-Cu-LSGM are compatible with LSGM electrolyte. However, lacking of electrocatalytic activity of Cu leads to higher anode overpotentials and smaller exchange current density. The Ni-Cu-LSGM is not thought to be a suitable anode material for intermediate-temperature LaGaO3 -based solid oxide fuel cells operating below 800 degrees C. The catalytic activity of this anodic material may be further improved through adding appropriate amount Of Sm2O3-doped CeO2 to Ni-Cu-LSGM. (c) 2004 Elsevier B.V. All rights reserved.