Muhammad, Q. K., Scherer, M., Opitz, A. K., Taibl, S., Boehme, C., Rohnke, M., Janek, J., Gao, S., Fleig, J., & Frömling, T. (2022). Dislocation-Mediated Oxygen–Ionic Conductivity in Yttria-Stabilized Zirconia. ACS Nano, 16(10), 16655–16667. https://doi.org/10.1021/acsnano.2c06121
Yttria-stabilized zirconia (YSZ) has become an indispensable solid electrolyte material in modern solid oxide fuel and electrolysis cells (SOFCs/SOECs) as well as oxygen sensors. The oxygen ionic conductivity of YSZ is among the highest known so far. For energy efficiency optimization of SOFCs and lowering the high-temperature degradation of electrodes, the oxygen ionic conductivity needs to be further enhanced. This would allow for a reduction in application temperature. Despite extensive regular point defect-doping strategies, this key issue remains unsolved. Here, we investigate the role of mechanically induced dislocations (line-defects) on electrical conductivity and oxygen transport in bulk YSZ. An advanced mechanical deformation approach is employed to generate distinctly aligned dislocation-rich and -deficient regions. The in-depth electrical characterization of these regions exhibited highly conducting effects of dislocation-Induced strain inside the bulk material. Furthermore, targeted oxygen tracer diffusion experiments prove enriched oxygen incorporation within the dislocation bundles. Therefore, the potential of mechanically induced dislocations is elucidated as a design element to tune the bulk ionic transport in YSZ.
