화학공학소재연구정보센터
Journal of Physical Chemistry A, Vol.116, No.1, 309-318, 2012
Self-Diffusion of Lithium in LiAlSi2O6 Glasses Studied Using Mass Spectrometry
In order to improve our understanding of the transport mechanism's of lithium in glasses, we have performed diffusion and ionic conductivity studies on spodumene composition (LiAlSi2O6) glasses. In diffusion couple experiments pairs of chemically identical glasses with different lithium isotopy (natural Li vs pure Li-7) were processed at temperatures between 482 and 732 K. Profiles of lithium isotopes were measured after the diffusion runs innovatively applying femtosecond UV laser ablation combined with inductively coupled plasma mass spectrometry (LA ICP-MS). Self-diffusion coefficients of lithium in the glasses were determined by fitting the isotope profiles. During some of the diffusion experirnents the electrical conductivity of the samples was intermittently measured by impedance spectrometry. Combining ionic conductivity and self diffusivity yields a temperature-independent correlation factor of similar to 0.50, indicating that motions of Li ions are strongly correlated in this type of glasses. Lithium self diffusivity in LiAlSi2O6 glass was found to be very similar to that in lithium silicate glasses although Raman spectroscopy demonstrates structural differences between these glasses; that is, the aluminosilicate is completely polymerized while the lithium silicate glasses contain large fractions of nonbridging oxygen.