Nanostructured functional layers for solid oxide fuel cells

Abstract

Nanostructured coatings are fabricated for potential use as electrodes in solid oxide fuel cells (SOFC) by developing innovative plasma spraying methods. The nanostructured NiO+YSZ anodes are fabricated by three means: spraying of presynthesized agglomerates of nanoparticles, suspension dc plasma spraying and solution precursor dc plasma spraying. Cathode deposits of variety of chemical composition having nanostructure were fabricated by thermal plasma chemical vapor deposition (TP-CVD) using RF-plasma torch. The deposits of desired phase and microstructure were successfully produced. The nanostructured anode, fabricated by presynthesized agglomerates of nanoparticles, exhibited better gas permeability, comparable high temperature conductivity and 43% lower polarization in SOFC operation at 800°C compared with conventional anodes. Moreover, by controlling the electrode structure, the nanostructure of anode could be maintained for 1500 h of operation. Further improvement in the microstructure of anodes is in progress using dc plasma suspension and solution precursor spraying. Cathodes obtained from thermal plasma chemical vapor deposition (TPCVD) exhibited initially undesirable secondary phases, which were overcome by adjusting the chemical composition of the precursors. The deposit columnar structure had high open porosity and specific surface area. Copyright © 2009 John Wiley & Sons, Ltd.