Plasma Spray Processing of Solid Oxide Fuel Cells

Abstract

Plasma spray processing is a low-cost, rapid manufacturing technique that is widely used industrially for fabrication of thermal barrier and wear- and corrosion-resistant coatings. Because the technique can be used to rapidly deposit coatings of high melting temperature materials with good substrate adhesion, it has also been applied to the production of individual component layers in tubular solid oxide fuel cells (SOFCs), and more recently, in planar SOFCs. The use of plasma spray processing for the fabrication of fuel cell components presents unique challenges, due to the high porosities required for the electrode layers and fully dense coatings required for electrolytes. Application of plasma spray processing for the manufacture of solid oxide fuel cells is discussed, with consideration of potential advantages of the technique compared to standard SOFC wet ceramic processing routes. Major challenges faced in the adaptation of the processing method to solid oxide fuel cell manufacture are discussed, along with current research approaches being used to overcome these challenges. Recent developments in the use of the technique for the rapid onestep manufacturing of direct oxidation SOFC anodes are discussed, for composite material combinations that cannot be co-sintered due to widely divergent melting points. The impacts of plasma sprayed coating properties on solid oxide fuel cell performance are considered, and implications of the use of the technique on overall stack and system manufacturing costs are discussed.