Magnesium (II) bis(trifluoromethanesulfonimide) doped PVdC-co-AN gel polymer electrolytes for rechargeable batteries

Abstract

Gel polymer electrolytes (GPEs) containing poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN) as the polymer host and plastic crystal succinonitrile (SN) as plasticizer were prepared with varied concentrations of 5 to 30 wt.% of magnesium (II) bis(trifluoromethanesulfonimide) Mg(TFSI)2 salt. The highest room temperature ionic conductivity of 1.61 × 10−6 S cm−1 was obtained from the sample containing 20 wt.% of Mg(TFSI)2. The conductivity temperature dependence studies of the GPE system was found to obey the VTF relation. To study the interaction among the constituents in the GPEs as well as to confirm the complexation between them, Fourier transform infrared spectroscopy. (FTIR) was carried out. The analysis of FTIR spectra was further investigated by deconvolution of the FTIR spectra to prove the dependability of ionic conductivity with the presence of free ions, ion pairs, and ion aggregates in the GPEs. The amorphous nature of the GPEs were confirmed by X-ray diffraction (XRD) analysis while DSC studies revealed the relationship between the thermal stability of GPEs and ionic conductivity. The electrochemical study was also performed by linear sweep voltammetry (LSV) to verify the maximum withstand voltage of the electrolyte to be used in magnesium battery application.