The atomic structures of ceramics critically govern their thermal properties. However, the atomistic thermal transport mechanisms are poorly understood. Here, we developed novel neural network potentials with near-DFT accuracy, enabling a precise exploration of atomic structural evolution in yttria-stabilized zirconia and its influence on thermal properties. It was found that the monoclinic-to-tetragonal transition is primarily driven by tilt vibrations, whereas the tetragonal-to-cubic transition is mainly governed by octahedral distortions. Yttrium doping and the resulting oxygen vacancies induce local stress and lattice mismatch, thereby shifting the transition temperatures. As the doping concentration increases, the energy barriers between different YSZ phases decrease, thus facilitating phase transitions. Meanwhile, the lattice thermal conductivities are mainly related to low-frequency acoustic branches, exhibit size effects, and are insensitive to anisotropy. Further analysis of phonon lifetimes reveals that yttrium doping and the associated oxygen vacancies enhance lattice anharmonicity and defect scattering. This work provides a theoretical framework for analyzing the structure-dependent thermal properties of advanced oxide ceramics.

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• Atomic & molecular structure
• Ab initio molecular dynamics
• Density functional theory
• Molecular dynamics