Effect of lithium bis(trifluoromethylsulfonyl)imide salt-doped UV-cured glycidyl methacrylate

A study is carried out on solid polymer electrolytes (SPEs) based on UV-curable glycidyl methacrylate (GMA) reactive mixtures to determine the lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) effect at different weight percentages. These polymeric systems are discussed considering several factors such as chemical interaction, structural and thermal properties, ionic conductivity, and lithium transference number. Samples are prepared using solution casting technique and are analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS) characterization methodologies. FTIR spectra show that interaction occurs between electronegative atoms in polymer host and TFSI− ions. XRD diffractogram indicates the amorphous aspect of SPEs, without the presence of LiTFSI peaks. Doping with LiTFSI salt reduces the glass transition temperature of SPEs and increased their ionic conductivity. Identified as the ideal salt concentration for poly(glycidyl methacrylate) (PGMA)-LiTFSI SPE system is 30 wt.% LiTFSI doping level, thus achieving a ionic conductivity of 3.69 × 10−8 S cm−1 at ambient temperature and 1.23 × 10−4 S cm−1 at 373 K. The ionic conductivity behavior obeys the Vogel–Tamman–Fulcher equation with an activation energy of 0.054 eV.