Improved power generation performance of solid oxide fuel cells using doped LaGaO3 electrolyte films prepared by screen printing method II. Optimization of Ni–Ce0.8Sm0.2O1.9 cermet anode support

Abstract

A Ni and Sm-doped ceria (Ce0.8Sm0.2O1.9, SDC) cermet anode as a porous support of doped LaGaO3 film prepared by a wet coating and co-firing process was investigated. Different preparation methods and compositions were used to improve the power density of intermediate temperature solid oxide fuel cells. NiO–SDC precursor powder with fine particles and a porous microstructure with high surface area was synthesized by a modified impregnation method and compared with that synthesized by a ball milling method. In addition, an open circuit voltage, which is almost equal to the theoretical value of 1.1 V, and maximum power densities of 835, 277, and 67 mW cm−2 at 700, 600, and 500 °C, respectively, were achieved on a single cell supported by a 75 wt% Ni–SDC cermet anode when a 60 μm thick Sr- and Mg-doped lanthanum gallate (LSGM) electrolyte was used. The improved power density was explained by the enlarged reaction area for the anode as a result of the low polarization resistance of the anode by high porosity and uniform distribution of Ni and SDC particles. Although a small amount of Ni diffused to the interface between the La-doped ceria (LDC) buffer layer and the LSGM electrolyte film, an adverse reaction that deteriorates cell performance seemed to be suppressed, and thus, reasonably high power density was achieved on the cell using the LSGM film prepared by the screen printing method with optimization of the anode substrate structure and composition.