Si/Li2S Battery with Solvate Ionic Liquid Electrolyte

A lithium-sulfur cell was developed, consisting of a Si nanoflake negative electrode, a Li2S/graphene positive electrode, and a non-flammable solvate ionic liquid electrolyte. This cell configuration allows us to avoid the use of Li metal electrode and the concomitant dendritic deposition of Li metal at the negative electrode during charging, thereby rendering the cell operation highly safe and stable. The solvate ionic liquid electrolyte solution was composed of tetraglyme, lithium bis(trifluoromethanesulfonyl)amide, and a hydrofluoroether. The solubility of lithium polysulfide (reaction intermediate of the positive electrode) is very low, resulting in high Coulombic efficiency of discharge/charge and long cycle life of the Si/Li2S cell. (C) The Electrochemical Society of Japan, All rights reserved.