Anisotropic mechanical behavior of gadolinia-doped ceria solid electrolytes under electromechanical coupling field using atomistic simulations

Abstract

Gadolinia-doped ceria (GDC) is one of widely used electrolyte materials for solid oxide fuel cells (SOFCs) due to its high ionic conductivity. In this paper, we report the anisotropic mechanical behavior of GDC solid electrolytes under electromechanical coupling loading by molecular dynamics (MD) simulation. For pure CeO2, it is found that low electric field merely reduces the fracture strength while high electric field directly changes phase transformation behavior in the [100] and [110] crystal orientations. In the [111] crystal orientation, the increase of electric field lead to the synchronous elevation of fracture stress by weakening the electrostatic repulsion between adjacent oxygen ions. And the doping concentration and temperature are considered to investigate the fracture behavior with electric field loading. Moreover, significant improvement of electrolyte conductivity is obtained by loading electric field on GDC. This finding might be able to provide a reasonable insight to reduce operating temperature of SOFC system.