A highly stretchable gel-polymer electrolyte for lithium-sulfur batteries. (10th March 2017)

• Record Type: Journal Article
• Authors: Choudhury, Soumyadip; Saha, Tuhin; Naskar, Kinsuk; Stamm, Manfred; Heinrich, Gert; Das, Amit
• Is Part Of: Polymer. Volume 112(2017)
• Page Start: 447
• Page End: 456
• Publication Date: 2017-03-10
• Subjects: Stretchable elastomeric electrolyte -- Polyepichlorohydrin terpolymer -- Lithium-sulfur battery; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2017.02.021
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: A stretchable gel-polymer electrolyte (GPE) based on polyepichlorohydrin terpolymer as a host polymer, a mixture of 1, 3-dioxolane and 1, 2-dimethoxyethane as plasticizers and lithium bis(trifluoromethane)sulfonimide (LiTFSI) as salt was developed and studied in detail. GPEs were prepared in a two-step process. The cross-linked polyepichlorohydrin network was developed using ethylene thiourea (ETU) and magnesium oxide (MgO) as cross-linkers. An immersion method was used for distribution of LiTFSI-salt in the network film. The effects of electrolyte uptake on mechanical and thermal properties of GPEs were studied in detail. Dynamic mechanical analysis (DMA) shows a GPE with a storage modulus higher than 0.6 MPa at ambient temperature (298 K). Differential scanning calorimetry (DSC) analysis was carried out on the GPE to demonstrate the change in glass transition temperature caused by the addition of two plasticizers. Impedance spectroscopy was used to study the ionic conductivity in the GPE. The highest ionic conductivity was found to be 2.4 × 10 −4 S/cm at 298 K. The lithium-sulfur cells in conjunction with the elastomeric gel-polymer electrolyte showed characteristic cyclic voltammograms and charge-discharge plateaus indicating a two stage reduction process and a one stage oxidation process. The battery demonstrated initial specific capacity of 700–800 mA h/gsulfur which faded slowly with cycle number. Our present work could pave a new route to fabricate flexible rechargeable batteries with a cross-linked soft polymer electrolyte. Graphical abstract: Highlights: Commercial eplichlorohydrin based rubber was crosslinked with sulfur curatives. This rubber was used as a medium for solid electrolyte for lithium sulfur battery. The crosslinking density of the rubber determines the total uptake of lithium salts. Ionic conductivity values in the range of 10 −4 S/cm were achieved. The battery reached an initial specific capacity of 700–800 mA h/gsulfur .