SOFC용 Ni- 연료극의 전기 화학적 특성 및 장기 안정성 평가

Abstract

(PrCZO) which has higher oxygen storage/release ability and carbon coking tolerance, is employed as a substitute of an yttria-stabilized zirconia (YSZ) in conventional nickel-based solid oxide fuel cell (SOFC) anode (Ni-YSZ). According to electrochemical impedance spectroscopy (EIS) analysis of a symmetrical Ni-PrCZO/YSZ/Ni-PrCZO cell, the Ni-PrCZO anode shows superior initial performance than that of a conventional Ni-YSZ anode. However, despite its excellent initial performance, the Ni-PrCZO anode shows very unstable performance and continuously deteriorates with time even in humidified hydrogen atmosphere, the most basic anode operating environment. In this study, the gradual deterioration of the PrCZO-based anode under reducing atmosphere which is the fatal limitation in its implication to SOFC anode was investigated and compared with that of a conventional Ni-YSZ-based anode with respect to their structural integrities and the stabilities of their constituent phases. Basic cause analysis on the instability of PrCZO materials for the practical utilization of the PrCZO-based anodes are also addressed based on study of the electrode reaction mechanism.