Papers by Author: Dave Ghosh

Abstract: An SOFC must have sufficient mechanical strength and interface adhesion to ensure it can be handled without breakage during fabrication and assembly, and has desired performance and reliability. Methods for measuring mechanical properties and interface adhesion of an SOFC have been developed and measurements made on a cermet-supported SOFC with a SDC electrolyte. The SOFC evaluated had a porous NiO-YSZ substrate, a porous NiO-SDC anode and a dense SDC electrolyte fabricated using tape-casting, screen-printing and co-firing techniques. The flexural strength and interface adhesion of the substrate, the anode and the electrolyte, along with their Young’s modulus, hardness and residual stress, were quantitatively measured. The results of the measurements indicate that the NiO-YSZ supported, SDC electrolyte SOFC has adequate mechanical strength and sufficient interface adhesion.

Abstract: In this study, an addition of Co and Cu oxides to Sm0.2Ce0.8O1.9 (SDC) was studied to improve the SDC sinterability. It has been found that both Co and Cu oxide are very effective as sintering aids, and the SDC sintering temperature can be reduced from 1400°C without aids to below 1000°C with only 1at.% of either Cu or Co. As compared to the pure SDC, a slight decrease of ionic conductivity was observed in SDC with Cu sintering aid. There is no obvious effect on electrochemical property of SDC with Co sintering aid under 2.5at.%.

Abstract: Intermediate temperature SOFC components, such as dense, nanostructured SDC electrolytes (samarium doped ceria) and porous anode sublayers were fabricated by suspension plasma spraying using an axial feed dc plasma torch. The liquid carrier employed in this approach allowed for controlled injection of much finer particles than in conventional thermal spraying, leading to thin coatings with a refined microstructure. Dense, thin (<10(m) and non-fractured electrolytes were created. Various processing routes for SOFC half-cells, using tape-cased, plasmasprayed and suspension-sprayed anodes, were explored. Loss of integrity and non-continuous coverage of the anode constituted the principal difficulties in the subsequent electrolyte deposition. The role of suspension feedstock particle size is discussed. Amongst various schemes investigated, a processing route that employs sequential suspension plasma spraying steps for both the electrolyte and the anode, using relatively large primary particles in the feedstock, constituted the most promising approach.

Abstract: National Research Council (NRC) as the premier research and development organization within the government of Canada has the mandate of providing vital scientific and technological services to research and industrial communities. The NRC Institute for Fuel Cell Innovation (IFCI) is leading NRC’s National Fuel Cell Program and is working closely with academic, government, and industrial organizations to support fuel cell cluster in Vancouver and across Canada and to fulfill the innovation needs of Canadian fuel cell companies. The key programs at IFCI include: Proton Exchange Membrane Fuel Cells (PEMFC), Solid Oxide Fuel Cells (SOFC), Hydrogen generation and infrastructure, and technology demonstration. NRC-IFCI’s impact on the fuel cell industry can be seen through the development and transfer of targeted and collaborative research projects addressing strategic and current technical gaps and providing infrastructure for research, development and demonstration. IFCI has been a catalyst in the coordination of industry’s responses to current commercialization barriers. This paper presents the latest research and development activities as well as demonstrations at NRC-IFCI.