Electrochemical and spectroscopic investigations of a gel polymer electrolyte of poly(methylmethacrylate) and zinc triflate

A gel polymer electrolyte (GPE) film comprising poly(methyl methacrylate), ethylene carbonate (EC), propylene carbonate (PC) and zinc triflate (ZnTr) is prepared and characterized by electrochemical and spectroscopic techniques. The GPE is optimized to contain minimum quantity of the liquid components required for the gel formation with a maximum specific conductivity $(\sigma)$ of $(1.3\pm 0.45)\times 10^{-3}\hspace {2mm} S \hspace {2mm} cm^{-1}$ at $(27\pm1)\hspace {2mm} ^oC$. The variation of $\sigma$ with temperature follows an Arrhenius behavior and the activation energy for the optimum composition is determined to be 0.19 eV. Ac impedance and cyclic voltammetric studies indicate electrochemical activity of $Zn/Zn^{2+}$ couple in the GPE. Cyclic voltammetry and charge–discharge cycling studies reveal intercalation/deintercalation of $Zn^{2+}\hspace{2mm}in \hspace {2mm} \gamma-MnO_2$. FT-Raman spectroscopy has been used to follow the changes in the ionic environment in the GPE. The symmetric stretching mode of triflate anion $(v_sSO_3)$ has been used as a probe to follow the presence of free ions, ion pairs and higher aggregates