Ionic conductivity studies of LiBOB-doped silyl solvent blend electrolytes for lithium-ion battery applications

• LiBOB/silyl solvent blend electrolytes achieve high ionic conductivities.
• Conductivities are optimized at 0.8 M LiBOB and equal volumes of two silyl solvents.
• Electrolyte conductivities meet the threshold required for commericial application.
• LiBOB/silyl solvent blend electrolytes are stable to 4.6 V vs. Li/Li+.
• LiBOB/blend electrolytes achieve higher conductivities than pure silyl electrolytes.

The ionic conductivity of LiBOB-doped electrolytes containing two silyl solvents, bis[2-(2-methoxyethoxy)ethoxy] dimethylsilane, 1, and [2-(2-methoxyethoxy)ethoxy] trimethylsilane,2, was measured from −10 °C to 50 °C using AC impedance spectroscopy to assess their potential use in commercial Li-ion cells. The effects of salt concentration, solvent composition, and temperature on the conductivity of the electrolytes are reported. In addition, conductivity data were fit using the Vogel-Tamman-Fulcher (VTF) equation to obtain the parameters σ0, T0, and Ea, which correspond closely to conductivity and viscosity. All the electrolytes produced conductivities above the 1.0 mS cm−1 threshold required for commercial application. The 1:1 (vl) solvent composition possesses the highest conductivity, with the optimal 0.8 M salt-loading yielding the highest σ25 at 1.99 ± 0.02 mS cm−1.