Revisiting TEGDME/DIOX Binary Electrolytes for Lithium/Sulfur Batteries: Importance of Solvation Ability and Additives

The lithium/sulfur (Li/S) battery is a promising electrochemical system having a high theoretical capacity of 1675 mA h(-1) However; this system suffers from several drawbacks: poor active material conductivity, active material dissolution, and use of the highly reactive lithium metal electrode. In this study, TEGDME/DIOX binary electrolyte compositions and their effect on both discharge capacity and cycle life of Li/S cells have been revisited. Electrochemical response has been studied taking into account various solvent ratios, lithium salt concentration and use of additives. The solvation ability of the electrolyte was found to be a key factor for high electrochemical performances. The poor performances obtained with high DIOX contents were associated to insufficient solvation ability and DIOX polymerization. It could also be assumed that efficient lithium metal passivation was achieved, as no resistive layer associated to lithium sulfide deposition on the negative electrode could be observed by impedance measurements. (C) 2013 The Electrochemical Society. [DOI: 10.1149/2.022303jes] All rights reserved.