Transport properties of a new Li+ ion-conducting ormolyte: (SiO2–PEG)–LiCF3SO3

Abstract

The transport properties of a new fast Li⁺ ion-conducting sol–gel-derived ormolyte, (SiO₂–10 wt% PEG)–[Li/O] LiCF₃SO₃, with [Li/O] = 0–0.1 (mol/mol), is reported. The composition with [Li/O] = 0.04 exhibited the highest conductivity (σ_{25 °C} = 1 × 10⁻⁴ S cm⁻¹), with an enhancement of 10³ over the host matrix (SiO₂–10 wt% PEG xerogel), and has been found to be the ‘optimum conducting composition’. Direct determination of Li⁺ ion mobility (μ) and mobile ion concentration (n) revealed that the enhancement was due to the increase in both μ and n. Studies of the variation of σ, μ, and nversus temperature indicated that the system shows Arrhenius-type behavior. The activation energy and energies of migration and formation were evaluated from their respective Arrhenius plots. Measurement of the ion transference number (t_ion) confirmed that the ions are the sole charge carriers in the system. These results are discussed in the light of existing theories.