Lithium conductivity in glasses of the Li₂O–Al₂O₃–SiO₂system

Abstract

To improve the understanding of Li-dynamics in oxide glasses, i.e. the effect of [AlO 4 ] À tetrahedra and non-bridging oxygens on the potential landscape, electrical conductivity of seven fully polymerized and partly depolymerized lithium aluminosilicate glasses was investigated using impedance spectroscopy (IS).Lithium is the only mobile particle in these materials. Data derived from IS, i.e. activation energies, preexponential factors and diffusivities for lithium, are interpreted in light of Raman spectroscopic analyses of local structures in order to identify building units, which are crucial for lithium dynamics and migration. In polymerized glasses (compositional join LiAlSiO 4 -LiAlSi 4 O 10 ) the direct current (DC) electrical conductivity continuously increases with increasing lithium content while lithium diffusivity is not affected by the Al/Si ratio in the glasses. Hence, the increase in electrical conductivity can be solely assigned to lithium concentration in the glasses. An excess of Li with respect to Al, i.e. the introduction of non-bridging oxygen into the network, causes a decrease in lithium mobility in the glasses. Activation energies in polymerized glasses (66 to 70 kJ mol À1 ) are significantly lower than those in depolymerized networks (76 to 78 kJ mol À1 ) while pre-exponential factors are nearly constant across all compositions. Comparison of the data with results for lithium silicates from the literature indicates a minimum in lithium diffusivity for glasses containing both aluminium tetrahedra and non-bridging oxygens. The findings allow a prediction of DC conductivity for a large variety of lithium aluminosilicate glass compositions.

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.…”

Consequences of sp2–sp3 boron isomerization in supercooled liquid borates

“…Lithium ion conductivity is known to decrease with the introduction of non-bridging oxygen 9,34,35 and, therefore, with a decrease in N 4 due to boron isomerization. Our findings are, therefore, consistent with the complex composition-temperature dependence measured in molten lithium borates.…”

Structural dependence of crystallization in glasses along the nepheline (NaAlSiO4) ‐ eucryptite (LiAlSiO4) join

“…Considering the scientific and technological importance of glasses in the nepheline-eucryptite system, the overarching goal of this work was to understand the structural dependence of crystalline phase evolution in the glasses as a function of Na/Li ratio. While numerous studies have been conducted on the NaAlSiO 4 -SiO 2 system, 29,30 the LiAlSiO 4 -SiO 2 system, [31][32][33][34][35] and the Li 2 SiO 3 -LiAlSiO 4 system, 36,37 only a few have been conducted on the (Li,Na) AlSiO 4 system, as described below. Some notable studies on the alkali-substituted spodumene system (Li,Na)AlSi 2 O 6 include that of Wang et al 38…”