Atomic Resolution Distortion Analysis of Yttrium-Doped Barium Zirconate

Ionic transport dynamics underpins the functionality of most energy storage and conversion technologies. Yttrium-doped barium zirconate (Y-BZO) has attracted attention as a promising electrolyte for proton-conducting solid oxide fuel cells (PC-SOFCs), which stems from its high proton conductivity and excellent chemical stability at intermediate temperatures (400-700°C) [1]. The Grotthuss mechanism for proton conduction is envisioned to occur by the creation of oxygen vacancies (V0 ), which are induced by the substitution of Y 3+ atoms on Zr 4+ sites. Density functional theory (DFT) calculations have suggested possible V0 ∙∙ -dopant association effect and proton trapping effect [2]; however, experimental validation is lacking. To reveal the fundamental role of V0 ∙∙ and dopant concentration on the ionic transport mechanisms, and possible proton trapping effects in Y-BZO, it is important to understand how defect are created and distributed at the atomic scale. Recently, it has been shown that local distortions in lanthanum strontium aluminium titanate (LSAT) can be directly measured, with pm-level precision, using atomic-resolution aberration-corrected scanning transmission electron microscopy (STEM) [3]. A similar, detailed understanding of local distortion in Y-BZO would help elucidate the correlation between point defects and lattice distortions and their role on proton conduction.