Fast Oxygen Transport in Bottlelike Channels for Y-Doped BaZrO3: A Reactive Molecular Dynamics Investigation

Abstract

Yttrium-doped barium zirconate (BZY) has emerged as an attractive candidate of oxygen ion (O2–) conducting solid electrolyte because of its high ionic conductivity and excellent chemical stability. In this work, the O2– transport properties and mechanisms of BZY coexisting oxygen vacancies, dopants, and edge dislocations are simulated by reactive molecular dynamics for the first time, and the yttrium concentration (Y%) and temperature (T) dependences of thermodynamic and kinetic properties are studied for the bulk and dislocation (Bulk and Disl) systems, respectively. It is concluded that the Y% under 20 mol % for Bulk BZY can promote O2– conduction, while 30 mol % Y-doped Disl BZY has the highest O2– diffusion coefficient. Besides, dislocations will accelerate O2– diffusion when T is less than 1173.15 K due to the formation of double-bottle diffusion channels that enables facile reorientation of oxygen polyhedron. Therefore, it is feasible to introduce line defects to enhance ion conductivity at low temp...