Influence of B site Substituents on Lanthanum Calcium Chromite Nanocrystalline Materials for a Solid-Oxide Fuel Cell

• Published in: Journal of the American Ceramic Society 2007-12, Vol.90 (12), p.3741-3747
• Main Authors: Ghosh, Saswati, Sharma, Abhijit Das, Basu, Rajendra Nath, Maiti, Himadri Sekhar
• Format: Article
• Language: English
• Subjects: Applied sciences; Calcium; Ceramics; Cross-disciplinary physics: materials science; rheology; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Materials science; Microstructure; Nanocrystals; Nanopowders; Nanoscale materials and structures: fabrication and characterization; Physics
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.2007.01987.x

Highly reactive and nanocrystalline powders of LaCrO3based compositions, having the general formula La0.9Ca0.1Cr1−xMxO3−δ (0≤x≤0.1, and M=Al, Co, or Mg), suitable for solid‐oxide fuel cell (SOFC) applications, have been synthesized using an auto‐combustion technique with ammonium dichromate as the chromium source. Owing to very fine crystallite size (ranging from 10 to 50 nm) and the high reactivity of the powders (surface area as high as 25 m2/g), the sintering temperature reduces drastically and a highly dense, uniform, and fine‐grained microstructure is obtained. A dramatic improvement in densification (nearly theoretical density) is observed for aluminum substitution, when sintered at as low a temperature as 1300°C. The microstructure shows a uniform distribution of grains having an average grain size of ∼0.5 μm. Depending on the substituent, the electrical conductivities of the sintered samples in air, at 1000°C, were found to be in the range of 10–45 S/cm, and are more than that of the values required for SOFC application. The thermal expansion coefficients, as obtained, are also comparable with the other SOFC cell components.