Solid composite polymer electrolytes with high cation transference number

This work presents the electrochemical and structural study of the dual modified composite LiBOB-based polymer electrolyte. Modification has been carried out by calix[6]pyrrole (CP) anion trap and nanosize silica filler. The main advantage of the use of LiBOB salt is the high ionic conductivity at near-ambient temperatures and low solid-electrolyte interphase (SEI) resistance. The conductivity of LiBOB:PEO₂₀:CP_0.125 with SiO ₂ is slightly lower than 10^-5 Scm^-1 at 30 °C, a value higher by about two orders of magnitude than that of the semi-crystalline LiCF₃,SO₃, (LiTf)-PEO system. At 75 to 90 °C the bulk ionic conductivity of modified LiBOB polymer electrolyte approaches 1 mScm^-1. The transference number of dual-modified LiBOB-polymer electrolyte is about 0.8 at 75 °C. Cyclic voltammetry tests showed a wide electrochemical stability window of the composite polymer electrolyte. The peak power of Li/MoO_xS_y cell with the polymer electrolyte film containing CP and SiO₂ reaches 2.2 mW/cm² and 3.0 mW/cm^-2 at 90 and 110 °C, respectively.