화학공학소재연구정보센터
International Journal of Energy Research, Vol.42, No.15, 4909-4916, 2018
Modeling cooperative creep reoxidation effect on the mechanical stability of anode-supported solid oxide fuel cell
Mechanical stress which develops during redox or creep of nickel-doped yttria-stabilized zirconia (Ni-YSZ) anode has been widely recognized as an important limitation for structural stability and commercialization of solid oxide fuel cell (SOFC). In this paper, the cooperative effect of reoxidation after creep (termed creep reoxidation) arising from abnormal operation condition on the mechanical robustness of SOFC is studied. In order to simulate inhomogeneous oxidation of Ni-YSZ at operation temperature, a continuously gradient model with gradients in material properties and local swelling induced by reoxidation is proposed. The stress level, oxidation tolerance, and curvature changes of a half cell undergoing reoxidation after various creep durations are compared. The present study highlights that the stress relaxation due to the creep of anode cermet in operation leads to a higher stress in electrolyte and a lower oxidation tolerance of the cell during the subsequent oxidation stage.