Effects of Nanoscale PEALD YSZ Interlayer for AAO Based Thin Film Solid Oxide Fuel Cells

Performance of thin film solid oxide fuel cells (TF-SOFCs) were improved by inserting plasma enhanced atomic layer deposition (PEALD) of yttira-stabilized zirconia (YSZ) interlayers. By controlling the ratio between Y₂O₃ and ZrO₂ in YSZ deposition supercycles, Y₂O₃ mol.% in YSZ films were changed. High Y₂O₃ contained PEALD YSZ interlayered cell showed higher maximum power density (123.6 mW/cm² at 500 °C, 286.1 mW/cm² at 550 °C) and smaller polarization resistance compared with reference Y₂O₃ concentrated PEALD YSZ interlayer cell. (108.5 mW/cm² at 500 °C, 181.1 mW/cm² at 550 °C) Exchange current densities of TF-SOFCs at 500 °C also improved ~ 59.3% at high Y₂O₃ concentrated PEALD YSZ interlayer cells. These phenomena caused by high density of oxygen vacancies in high Y₂O₃ concentrated PEALD YSZ interlayer, which helps oxygen incorporation reactions at cathode-interlayer interface. Therefore, cathodic polarization loss related with oxygen reduction reactions was decreased, and then, performance and exchange current density were improved. Results of this study imply that insertion of simple PEALD YSZ interlayer at cathode-electrolyte interface efficiently improves performance and electrochemical characteristics of TF-SOFCs.