Self-Diffusion of Lithium in LiAlSi₂O₆ Glasses Studied Using Mass Spectrometry

Abstract

In order to improve our understanding of the transport mechanisms of lithium in glasses, we have performed diffusion and ionic conductivity studies on spodumene composition (LiAlSi(2)O(6)) glasses. In diffusion couple experiments pairs of chemically identical glasses with different lithium isotopy (natural Li vs pure (7)Li) 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 experiments 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 ~0.50, indicating that motions of Li ions are strongly correlated in this type of glasses. Lithium self-diffusivity in LiAlSi(2)O(6) 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.

Lithium conductivity in glasses of the Li2O–Al2O3–SiO2system

“…Diffusivities for the different polymerized glasses are practically indistinguishable. For LiAlSi 2 O 6 the data are in good agreement with the results of lithium isotope exchange experiments 49 and NMR measurements. 50 There appears to be a trend of slightly increasing activation energy for lithium diffusion with increasing silica content of the glass, but the effect is rather small compared to the error of E a ( Table 2).…”

Structural Origin of the Thermal and Diffusion Behaviors of Lithium Aluminosilicate Crystal Polymorphs and Glasses

“…The results showed that the highest conductivity could reach ~3 × 10 −5 Ω −1 cm −1 at 100°C, and the variation in conductivity with composition was due to changes in both the conduction activation energy and the mobile ion concentration. Welsch et al performed diffusion and ionic conductivity studies on LiAlSi 2 O 6 glass and it was found that the lithium self‐diffusivity in LiAlSi 2 O 6 glass was very similar to that in lithium silicate glasses . Despite wide range of experimental studies, detailed understanding of the structure–property relationship, especially on the ionic diffusion and thermal mechanical behaviors, in LAS materials is still missing.…”

Surface modification of Li(Li0.17Ni0.2Co0.05Mn0.58)O2 with LiAlSiO4 fast ion conductor as cathode material for Li-ion batteries

“…Some ionic conductors, such as LiTaO 3 [26], Li 3 VO 4 [27], LiAlO 2 [28] and Li 2 O-B 2 O 3 [29] have been considered to be ideal modifying materials for Li- [30,32,33]. One Li-ion can jump into adjacent sites introducing a vacancy which can be filled by another Li-ion.…”