Preparation and Characterization of Ni–LaNbO4 Cermet Anode Supports for Proton-Conducting Fuel Cell Applications
Abstract:Cermets of nickel (Ni)- and Ca-doped LaNbO4 (Ni–LCNO) with a composition ranging from 20 to 70 vol% Ni have been prepared by conventional mixing, cold-pressing, sintering, and reducing NiO–LCNO composites. They have been characterized by scanning electron microscopy, X-ray diffraction, four-point DC conductivity, and dilatometry. The conductivity of the cermets is metallic with values of 2000–4600 S/cm for 40–60 vol% Ni at 800°C, and increases with an increasing Ni content. There is no evidence of interdiffusion or the formation of secondary phases between LCNO and NiO or Ni. Thermal expansion coefficients for the cermets after reduction are reported, e.g. 16.9 × 10−6 and 12.5 × 10−6 K−1 corresponding to the low-temperature (250–450°C) and the high-temperature (650°–850°C) regions, respectively, for a 40% Ni–60% La0.995Ca0.005NbO4 cermet.
Document Type: Research Article
Affiliations: Department of Chemistry, University of Oslo, FERMiO, Gaustadalléen 21, NO-0349 Oslo, Norway
Publication date: 2010-09-01