Experimental investigations of an ionic-liquid-based, magnesium ion conducting, polymer gel electrolyte

• Published in: Journal of power sources Vol. 187; no. 2; pp. 627 - 634
• Main Authors: Pandey, G.P., Hashmi, S.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-02-2009; Elsevier
• Subjects: AC impedance spectroscopy; Anions; Applied sciences; Conducting polymers; Cyclic voltammetry; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrolytes; Exact sciences and technology; Gel polymer electrolyte; Ion transport; Ionic liquid; Ionic liquids; Magnesium; Magnesium batteries; Magnesium ion conductor; Scanning electron microscopy; Transport; Cyclic voltammetry; Gel polymer electrolyte; Magnesium batteries; Magnesium ion conductor; Ionic liquid; AC impedance spectroscopy; Ionic conduction; Measurement; Fourier transformation; Electrical conductivity; Electric batteries; Thermal stability; Electrochemical characteristic; Vinylidene fluoride polymer; Magnesium; Fourier-transformed infrared spectrometry; Scanning electron microscopy; Polymer electrolytes; Polymer gels; Secondary cell; Experimental study; Conducting polymers; X ray diffractometry; Impedance; Strength; Electrochemical impedance spectroscopy
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2008.10.112

Studies on a novel magnesium ion conducting gel polymer electrolyte based on a room temperature ionic liquid (RTIL) is reported. It comprises a Mg-salt, Mg(CF
3SO
3)
2 [or magnesium triflate, Mg(Tf)
2] solution in an ionic liquid, 1-ethyl-3-methylimidazolium trifluoro-methanesulfonate (EMITf), immobilized with poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), which is a freestanding, semitransparent and flexible film with excellent mechanical strength. Physical and electrochemical analyses demonstrate promising characteristics of these films, suitable as electrolytes in rechargeable magnesium batteries. The material offers a maximum electrical conductivity of ∼4.8
×
10
−3
S
cm
−1 at room temperature (20
°C) with excellent thermal and electrochemical stabilities. Possible conformational changes in the polymer host PVdF-HFP due to ionic liquid solution entrapment and ion–polymer interaction are investigated by Fourier transform infra-red (FTIR), X-ray diffraction (XRD) and scanning electron microscopic (SEM) methods. The Mg
2+ ion transport in the gel film is confirmed from cyclic voltammetry, impedance and transport number measurements. The Mg
2+ ion transport number (
t
+) is ∼0.26, which indicates a substantial contribution of triflate anion transport along with ionic conduction due to the component ions of the ionic liquid.