Measurement of ion mobility based on a reversible migration process in solids

Ion mobility, which facilitates ion migration in lattices, not only is important for selection of solid electrolytes from a large number of candidate materials but also plays an essential role in the study of the fundamentals of ion transport in solids. In the present work, a simple approach is developed for measuring the mobility of oxygen ions in a typical solid electrolyte, lanthanum-doped ceria. Changes in the concentration of oxygen vacancies, which are equivalent to variations in oxygen ions, are recorded using integrated peak intensity ratios of Raman spectra under a reversible electric field. A model of the migration process of oxygen ions in a reversing electric field is proposed based on the experimental results. The mobility of oxygen ions is determined by analyzing the time interval between two steady states based on a simplified model. By altering the electric field, this approach is applicable to the measurement of the mobilities of different ion species.Ion mobility, which facilitates ion migration in lattices, not only is important for selection of solid electrolytes from a large number of candidate materials but also plays an essential role in the study of the fundamentals of ion transport in solids. In the present work, a simple approach is developed for measuring the mobility of oxygen ions in a typical solid electrolyte, lanthanum-doped ceria. Changes in the concentration of oxygen vacancies, which are equivalent to variations in oxygen ions, are recorded using integrated peak intensity ratios of Raman spectra under a reversible electric field. A model of the migration process of oxygen ions in a reversing electric field is proposed based on the experimental results. The mobility of oxygen ions is determined by analyzing the time interval between two steady states based on a simplified model. By altering the electric field, this approach is applicable to the measurement of the mobilities of different ion species.