Improved zinc ion transportation in gel polymer electrolyte upon the addition of nano-sized SnO ₂

Nanocomposite gel polymer electrolytes (NCGPEs) consisting of Zn(OTf) ₂ salt solution in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid (EMIMTFSI), entrapped in poly(vinyl chloride) (PVC)/poly(ethyl methacrylate) (PEMA) matrices, and dispersed with different concentrations of tin oxide (SnO ₂ ) nanofiller were prepared by simple solution casting method. The free-standing film of the composite gel polymer electrolyte (GPE) exhibited an optimum ionic conductivity value of 4.92 × 10 ⁻⁴ Scm ⁻¹ at ambient temperature. The gel composites developed predominant amorphous phase and porous morphologies, thus supporting the high ionic conduction as confirmed from X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies. The complex formation properties of the materials were evaluated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy technique. The dispersion of nanofillers in GPEs improved the thermal behavior of the composite system to 185°C, which was ascertained by thermogravimetric (TG) analysis. The electrochemical stability window of approximately 4.37 V with feasible plating/stripping process of zinc metal on stainless steel electrode was analyzed by voltammetric studies and all these features suggested the possibility of exploiting NCGPE films as electrolytes in batteries.