Fabrication of Gd₂O₃-doped CeO₂ thin films through DC reactive sputtering and their application in solid oxide fuel cells

Abstract

Physical vapor deposition (PVD) can be used to produce high-quality Gd₂O₃-doped CeO₂ (GDC) films. Among various PVD methods, reactive sputtering provides unique benefits, such as high deposition rates and easy upscaling for industrial applications. GDC thin films were successfully fabricated through reactive sputtering using a Gd_0.2Ce_0.8 (at%) metallic target, and their application in solid oxide fuel cells, such as buffer layers between yttria-stabilized zirconia (YSZ)/La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ and as sublayers in the steel/coating system, was evaluated. First, the direct current (DC) reactive-sputtering behavior of the GdCe metallic target was determined. Then, the GDC films were deposited on NiO—YSZ/YSZ half-cells to investigate the influence of oxygen flow rate on the quality of annealed GDC films. The results demonstrated that reactive sputtering can be used to prepare thin and dense GDC buffer layers without high-temperature sintering. Furthermore, the cells with a sputtered GDC buffer layer showed better electrochemical performance than those with a screen-printed GDC buffer layer. In addition, the insertion of a GDC sublayer between the SUS441 interconnects and the Mn—Co spinel coatings contributed to the reduction of the oxidation rate for SUS441 at operating temperatures, according to the area-specific resistance tests.

Keywords

solid oxide fuel cell / physical vapor deposition / Gd₂O₃-doped CeO₂ / metallic interconnects / electrical conductivity

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