Three dimensional YSZ interface engineering layer for enhancement of oxygen reduction reactions of low temperature solid oxide fuel cells
Sangbong Ryu1, Wonjong Yu, Ikwhang Chang, Taehyun Park, Gu Young Cho#, Suk Won Cha#
In this study, we fabricated three dimensional yttria-stabilized zirconia (YSZ) interface engineering layer (IEL) by using a DC sputtering method to enhance oxygen reduction reactions (ORRs) of low temperature solid oxide fuel cells (LT-SOFCs). In order to deposit three dimensional YSZ IEL, a commercial Y–Zr metal alloy target was sputtered under various deposition pressure conditions (4, 8, 12 Pa) and then annealed at 800 °C for 6 h. Phase transformation of metal alloy Y–Zr to YSZ was identified by X-ray diffraction, X-ray photoelectron spectroscopy and high resolution-transmission electron microscope. The roughness of the three dimensional YSZ IELs were strongly related to the deposition pressure of the sputtering technique. After physical and chemical characterization, electrochemical examinations proved that the three dimensional YSZ IELs efficiently improved the ORR activity by geometrical effects. The fuel cell with the IEL fabricated at 8 Pa condition achieved the best power density (37.9 mW/cm2), which was 30.2% improved performance compared to the fuel cell without IEL (29.1 mW/cm2). Electrochemical impedance spectroscopy investigations also proved that rough three dimensional YSZ IELs efficiently enhance the performance of LT-SOFCs.