Induction Plasma Synthesis of Nano-Structured SOFCs Electrolyte Using Solution and Suspension Plasma Spraying: A Comparative Study

Abstract

In this paper, two plasma spraying technologies: solution plasma spraying (SolPS) and suspension plasma spraying (SPS) were used to produce nano-structured solid oxide fuel cells (SOFCs) electrolytes. Both plasma spraying processes were optimized in order to achieve the thin gas-tight electrolytes. The comparison of the two plasma spraying processes is based on electrolyte phase, microstructure, morphology, as well as on plasma deposition rate. The results show that nano-structured thin electrolytes (~5 lm thick) have been successfully SPS deposited on porous anodes with a high deposition rate. Compared to the electrolytes produced by SolPS, the SPS-deposited electrolyte layer is much denser. During the SPS process, fine droplets of 0.5-1 lm in diameter impact on the surface of the coating and penetrate into the pores of the anode. As the stresses are reduced on the resulting 0.5-2 lm splats, there is no apparent microcracks network on the splats, this resulting in highly gas-tight coatings. It is demonstrated that the SPS process is beneficial for the improvement of the performance of the films to be used as SOFC electrolytes.

Solution and Suspension Plasma Spraying of Nanostructure Coatings

“…The plasma-synthesized powders were almost globular in shape, and their BET specific surface areas were ∼26 m 2 .g -1 , i.e., about twice that of powders prepared by other routes. Jia and Gitzhofer (2010) elaborated coatings by r.f. plasma spraying of suspensions made of gadolinia-doped ceria (GDC) particles with a mean size of 0.6 µm dispersed in distilled water.…”

“…Plasma Spraying, called SolPS process by Jia and Gitzhofer (2010), GDC solutions of nitrate hexahydrate were completely vaporized in the plasma. Nano-structured GDC particles were synthesized in flight by homogeneous nucleation from the supersaturated precursor vapor and build up a coating with high porosity (Figure 11b) when impacting on a substrate.…”

Very Low Pressure Plasma Spray—A Review of an Emerging Technology in the Thermal Spray Community

“…Plasma spray technologies are already in use for solid oxide fuel cell (SOFC) preparation, but VLPPS has the potential for dramatic improvement over traditional plasma spray [9,15,[19][20][21][22][23][24][25]. Firstly, the VLPPS system provides dynamic control over the ambient chamber pressure during processing.…”

“…Firstly, the VLPPS system provides dynamic control over the ambient chamber pressure during processing. Thus, entire fuel cell systems can be constructed with measured or graded porosities to optimize each component in the cell [20][21][22][23]25]. In addition, the VLPPS process's ability to create thin and dense coatings makes it better suited than traditional thermal spray processes towards meeting the design criteria for SOFC electrolytes [9,15,19,20,22].…”

Fabrication of finely structured silicon-supported SOFC with anode deposited by multi-phase plasma spraying

“…Fauchais et al (2005) achieved a dense and thin (∼30 m) YSZ coating for the electrolyte using a suspension of YSZ powder (D 50 ∼ 1 m) which was mechanically injected into direct current plasma jets. Jia and Gitzhofer (2010) successfully prepared nano-structured thin electrolytes (∼5 m thick) by SPS. They demonstrated that the SPS process was beneficial for the improvement of the performance of the films to be used as SOFC electrolytes.…”