FORMATION OF YSZ ELECTROLYTE FILMS ON NiO-YSZ CATHODE SUBSTRATE BY DIP-COATING IN AQUEOUS SUSPENSIONS

One of the priority direction in the field of electrochemical devices for generating electricity is the development of solid oxide fuel cells (SOFC) operating at lower temperatures (below 600 ºC). The methods of forming a film electrolyte membrane are actively investigated when an improvement in the performance characteristics of the device occurs due to a decrease in the thickness of the electrolyte layer. As the electrolyte material of SOFC, zirconium oxide based on the solid solutions are most often used which have sufficient oxygen conductivity, chemical durability, and stability of physical properties in both oxidation and reducing atmospheres. The paper explores the yttria-stabilized zirconium oxide (YSZ) thin films prepared by dip-coating of NiO-YSZ substrates in an aqueous suspension followed by heat treatment and deals with some regularities of the crystallization of films on electrode substrates depending on the method of preparation of film-forming suspension, the surface morphology of the substrate, and heat treatment conditions of the film deposition. Optimum conditions for obtaining gastight film deposition on substrates with different porosity are determined. The effect of the components composition of the suspension (concentration of YSZ, dispersant), viscosity and pH of the system on the formation of film electrolyte was studied. Varying these parameters allows the YSZ film to be deposited with a thickness of 5–10 μm without cracks for 1–2 application cycles. The use of metal-ceramic compositions as anode materials due to the presence of the electrolyte phase is shown to increase the mechanical strength of the supporting electrode and provide more favorable conditions for the formation of the electrolyte film. The metal component is responsible for good electrophysical characteristics. For SOFC with an oxygen-ion electrolyte based on stabilized zirconium oxide, we discuss the composite anodes containing NiO and, accordingly, after reduction Ni as the metallic phase. This method is a simple and cost-effective for manufacturing a thin film electrolyte for solid oxide fuel cell.

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