Ionic Conductivity of Polymer Electrolytes

Abstract

AbstractIn this work, the effect of different salts: LiCF3SO3 (lithium triflate, LiOTf) and LiCl in 1:1 mole ratio in a methacrylate‐type polymer with zwitterionic pendant groups (PMBS‐4) used as host polymer, are evaluated. By means of X‐ray diffraction patterns, the formation of a homogeneous solution is observed in the case of PMBS‐4/LiCl and PMBS‐4/LiOTf. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) allows determination of glass transition temperatures (Tg) and thermal stability of the polymers. Tg values of the two polymer electrolytes are 293 ± 2 K against PMBS‐4 which is 291 K. The initial decomposition temperatures (IDT) for PMBS‐4 and PMBS‐4/Lithium salt are 483 K and 460 K, respectively. The ac ionic conductivity (σ) was obtained using the electrochemical impedance spectroscopy (EIS). It was found that σ increases as temperature rises following a simple Arrhenius behavior and reaches a value of ∼6 × 10−4 S/cm in the case of PMBS‐4/LiCl and ∼2 × 10−2 S/cm in the case of PMBS‐4/LiOTf, both measured at 343 K.