We report an electrolyte with low flammability, based on diethylene glycol dimethyl ether (DEGDME) dissolving lithium bis-trifluoromethane sulfonimidate (LiTFSI), and lithium nitrate (LiNO3) for high-performances lithium/sulfur battery. Self-diffusion coefficients, conductivity, and lithium transport number of the electrolyte are obtained by nuclear magnetic resonance and electrochemical impedance spectroscopy. Interface stability, lithium stripping/deposition ability, and the electrochemical stability window of the electrolyte are determined by voltammetry and impedance spectroscopy. The tests suggest conductivity higher than 10â2S cmâ1, lithium transport number of about 0.5, electrochemical stability extending from 0 V to 4.6 V, and excellent compatibility with lithium metal. A composite cathode using sulfur and multi walled carbon nanotubes (MWCNTs) is characterized in terms of structure and morphology by X-ray diffraction and scanning electron microscopy. The study shows spherical flakes in which the carbon nanotubes protect the crystalline sulfur from excessive dissolution, and create the optimal host for allowing the proper cell operation. The Li/S cell reveals highly reversible process during charge/discharge cycles, fast kinetic, and lithium diffusion coefficient in the sulfur electrode ranging from 10â12to 10â10cm2sâ1. The cell evidences a coulombic efficiency approaching 100%, capacity from 1300 mAh gâ1to 900 mAh gâ1and practical energy density higher than 400 Wh kgâ1.
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|Titolo:||A simple approach for making a viable, safe, and high-performances lithium-sulfur battery|
|Data di pubblicazione:||2018|
|Appare nelle tipologie:||03.1 Articolo su rivista|