Micro-hotplates -: A platform for micro-solid oxide fuel cells

Special high temperature micro-hotplates were investigated for their potential use as a technology platform for miniaturized solid oxide fuel cells (SOFCs). To evaluate the compatibility of these hotplates with typical SOFC materials and processing techniques, spray pyrolysis was used for the deposition of an SOFC cathode material (La0.6Sr0.4Co0.2Fe0.8O3, LSCF) onto the micro-hotplate. The resulting microstructures and the electrical conductivity of the thin film (thickness similar to 500 nm) were characterized. Post-deposition annealing in external furnaces as well as using the integrated heater of the micro-hotplate confirmed that these micro-hotplates are suitable for a maximum operation temperature of 800 degrees C and a long-term operation at 600 degrees C. Very fast heating and cooling rates of several 100 degrees C min(-1) were achieved using the micro-hotplate as a heater, allowing fast processing and aging tests. Bending of the micro-hotplate was found to be critical to the integrity of the thin film, which coats the micro-hotplate. Bending might be reduced using other membrane materials. These membranes are potential components for a micro-SOFC in which the integrated heater is used for start-up operation of the fuel cell. (c) 2007 Elsevier B.V. All rights reserved.