Effect of Different Cations on Ion-Transport Behavior in Polymer Gel Electrolytes Intended for Application in Flexible Electrochemical Devices

This paper reports the effect of different cations (Na, Mg and Li) while keeping perchlorate as the common anion on ion-dynamics behavior within polymer gel electrolytes containing tetraethylene glycol dimethyl ether (TEGDME) solvent and poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP) as the polymer host. FTIR investigations demonstrate significant changes in characteristic bands, while XRD observations indicate prominent structural variation in terms of merger/suppression of phases when NaClO4, Mg(ClO4)2 and LiClO4 salts are immobilized in the PVdF-HFP/TEGDME matrix. The highest room temperature ionic conductivity of 1.2 × 10−3 S cm−1 with high dielectric constant value has been obtained for the Li+ conducting electrolyte composition due to its superior electrochemistry and ion-conduction behavior as compared to its Na+ and Mg2+ counterparts. In the low-frequency region, modulus curves reveal polarizing effects with long-range mobility/migration of Na/Mg/Li ions, while in the high-frequency region, a peak onset relating the translational ion dynamics and conductivity relaxation is observed. The reported polymer gel electrolytes may be employed as electronic materials for developing next-generation flexible electrochemical devices.