Highly flexible and electrochemically stable Mg-ion conducting gel polymer electrolyte based on PVdF-HFP/PMMA blend for application in magnesium batteries

Herein, we report the physico-electrochemical characterization of a flexible film of Mg-ion conducting gel polymer electrolyte (GPE) based on a polymer blend of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and polymethyl methacrylate (PMMA). Accordingly, a liquid electrolyte, comprising of an Mg-salt [magnesium bis(trifluoromethane- sulfonyl)imide, Mg(TFSI)(2)] dissolved in an ionic liquid (1-ethyl-3-methyl imidazolium bis(trifluoromethanesulfonyl)imide, EMITFSI) was entrapped in the polymeric blend to form GPE-films. The blend formation of two polymers and amorphous character of the GPE-composition are confirmed via X-ray diffraction, whereas, the Fourier transform infrared and Raman spectroscopic studies indicate different possible interactions among the component materials of GPE. The high thermal stability (up to similar to 250 degrees C) and excellent electrochemical properties i.e., ionic conductivity (sigma similar to 6.1 mS cm(-1) at room temperature), wide electrochemical stability range (similar to 4.8 V vs. Mg/Mg2+), Mg-ion transport number (t(Mg)(2+) similar to 0.51), long-term interfacial resistances and stripping/plating behaviour at the interfaces of Mg|GPE|Mg cell indicate the suitability of GPE-film in Mg-batteries. The compatibility of the GPE-film as separator/electrolyte has been confirmed by assembling Mg-battery with Mg-anode and MnO2-incorporated cathode material. The battery offers discharge capacity of 100.6 mAh g(-1) for the first charge-discharge cycle and shows a gradual decrease in capacity up to 10 cycles.