Spectroscopic investigations of solvent assisted Li-ion transport decoupled from polymer in a gel polymer electrolyte

George, SM and Deb, D and Zhu, H and Sampath, S and Bhattacharyya, AJ (2022) Spectroscopic investigations of solvent assisted Li-ion transport decoupled from polymer in a gel polymer electrolyte. In: Applied Physics Letters, 121 (22).

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Abstract

We present here a gel polymer electrolyte, where the Li+-ion transport is completely decoupled from the polymer host solvation and dynamics. A free-standing gel polymer electrolyte with a high volume content (nearly 60) of xM LiTFSI in G4 (tetraglyme) (x = 1-7; Li+:G4 = 0.2-1.5) liquid electrolyte confined inside the PAN (polyacrylonitrile)-PEGMEMA poly (ethylene glycol) methyl ether methacrylate oligomer based polymer matrix is synthesized using a one-pot free radical polymerization process. For LiTFSI concentrations, x = 1-7 (Li+:G4 = 0.2-1.5), Raman and vibrational spectroscopies reveal that like in the liquid electrolyte, the designed gel polymer electrolytes (GPEs) also show direct coordination of Li+-ions with the tetraglyme leading to the formation of Li(G4)+. Coupled with the spectroscopic studies, impedance and nuclear magnetic resonance investigations also show that the ion transport is independent of the polymer segmental motion and is governed by the solvated species {Li(G4)+}, very similar to the scenario in ionic liquids. As a result, the magnitude of ionic conductivity and activation energies of the gel polymer electrolyte are very similar to that of the liquid electrolyte. The Li+-ion transport number for the GPE varied from 0.44 (x = 1) to 0.5 (x = 7) with the maximum being 0.52 at x = 5. © 2022 Author(s).

Item Type:	Journal Article
Publication:	Applied Physics Letters
Publisher:	American Institute of Physics Inc.
Additional Information:	The copyright for this article belongs to American Institute of Physics Inc.
Keywords:	Activation energy; Free radicals; Ionic liquids; Ions; Polyelectrolytes; Polyethylene glycols; Spectroscopic analysis, Free standings; Gel polymer electrolytes; High volumes; Ion-transport; Li +; Liquid electrolytes; Poly(ethylene glycol) methyl ether methacrylate (PEG-MMA); Polymer matrices; Spectroscopic investigations; Volume content, Free radical polymerization
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research
Date Deposited:	27 Jan 2023 09:52
Last Modified:	27 Jan 2023 09:52
URI:	https://eprints.iisc.ac.in/id/eprint/79566

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