Abstract:In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF 6 , until the Li-to-PEG ratio reached 1:4, with the conductivities of the LiAsF 6 /U-PEG blends being greater than those of the LiAsF 6 /U-PEG-U blends. The ionic conductivity of the LiAsF 6 /U-PEG system reached as high as 7.81 × 10 −4 S/cm at 30 °C. Differential scanning calorimetry, wide-angle X-ray scattering, 7 Li nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy revealed that the presence of the uracil groups in the solid state electrolytes had a critical role in tuning the glass transition temperatures and facilitating the transfer of Li + ions.