Study of Carbamate-Modified Disiloxane in Porous PVDF-HFP Membranes: New Electrolytes/Separators for Lithium-Ion Batteries

Authors

  • Steffen Jeschke,

    Corresponding author
    1. Institute of Inorganic and Analytical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster (Germany), Fax: (+49) 251-8336705
    • Institute of Inorganic and Analytical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster (Germany), Fax: (+49) 251-8336705===

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  • Dr. Monika Mutke,

    1. Institute of Inorganic and Analytical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster (Germany), Fax: (+49) 251-8336705
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  • Dr. Zhongxiang Jiang,

    1. Life Science Research Division, Leica Microsystems CMS GmbH, Am Friedensplatz 3 68165 Mannheim (Germany)
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  • Dr. Burkhard Alt,

    1. Life Science Research Division, Leica Microsystems CMS GmbH, Am Friedensplatz 3 68165 Mannheim (Germany)
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  • Prof. Hans-Dieter Wiemhöfer

    Corresponding author
    1. Institute of Inorganic and Analytical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster (Germany), Fax: (+49) 251-8336705
    • Institute of Inorganic and Analytical Chemistry, University of Münster, Correnstr. 28/30, 48149 Münster (Germany), Fax: (+49) 251-8336705===

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  • PVDF-HFP=poly(vinylidene fluoride–hexafluoropropylene)

Abstract

A gel electrolyte membrane is obtained through the absorption of a carbamate-modified liquid disiloxane-containing lithium bis(trifluoromethane)sulfonimide (LiTFSI) by using macroporous poly(vinylidene fluoride–hexafluoropropylene) (PVDF-HFP) membranes. The porous membranes are prepared by means of a phase inversion technique. The resulting gel electrolyte membrane is studied by using differential scanning calorimetry, Fourier-transform infrared (FTIR) spectroscopy, and microscope mapping through coherent anti-Stokes Raman scattering (CARS) confocal microscopy and impedance spectroscopy. The ionic conductivity of the gel electrolyte is 10−4 S cm−1 at 20 °C. FTIR spectroscopy reveals interactions between LiTFSI and the carbonyl moiety of the disiloxane. No interactions between LiTFSI and PVDF-HFP or between disiloxane and PVDF-HFP are detected by FTIR spectroscopy. Furthermore, the distribution of the α and β/γ phases of PVDF-HFP and the homogeneous distribution of disiloxane/LiTFSI in the gel electrolyte membranes are examined by FTIR mapping. CARS confocal microscopy is used to image the three-dimensional interconnectivity, which reveals a reticulated structure of macrovoids in the porous PVDF-HFP framework. Owing to properties such as electrochemical and thermal stability of the disiloxane-based liquid electrolyte and the mechanical stability of the porous PVDF-HFP membrane, the gel electrolyte membranes presented herein are promising candidates for applications as electrolytes/separators in lithium-ion batteries.

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