Rare earth zirconia-based electrolytes were investigated by molecular dynamics simulation in a spanning temperature of 1373 K to 1873 K in order to evaluate whether dopant size plays any role in ionic conductivity of oxygen ions. A new aspect of vibrational analysis was introduced to explain trend of the slope of Arrhenius plots (migration movement barrier, MMB). Vibrational spectra of atomic trajectory of cations and anions were calculated by Fourier transform analysis. The result demonstrates that electrolyte with smaller dopant suggests lower vibration in hopping plate cations (HPCs) and was verified by Zr4+ mean square displacement (MSD). Result of MSD indicated that dopant which is heavier (atomic mass) than Zr implies higher movement (or vibration). Thus, dopant vibration is responsible for MMB. A simple well-defined model was applied to investigate activation energy of oxygen ion hopping. It was found that lower vibrating HPC electrolyte deduces lower activation energy. First peak of O–O radial distribution function and 001 density distribution of oxygen ions claimed activation energy of oxygen hopping has direct correlation with oxygen scattering in the lattice structure. Thermal expansion and heat capacity as well were studied as important factors in heating operation. Although, results did not show relation between dopant size and these two thermal factors, it was found a linear relation between van der Waals and kinetic energy, respectively.

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