Materials Research Bulletin, Vol.95, 61-70, 2017
A stable graphite electrode in superconcentrated LiTFSI-DME/DOL electrolyte and its application in lithium-sulfur full battery
Herein, prelithiated graphite anodes are coupled with sulfur composite cathodes to form a Li-S full cell in superconcentrated ether electrolyte. This novel system is effective in avoiding sever corrosion of Li-metal anode and significantly improving the safety of present Li-S cell, owing to the replacement of Li-metal anode with graphite. The introduced superconcentrated ether electrolyte has a unique networking structure of Li cations and TFSI anions with Li+-solvating DME/DOL solvents, which is conducive to form a stable TFSI-derived surface film on the graphite electrode. The stable and dense TFSI-derived film inhibits further electrolyte decomposition and graphite exfoliation caused by co-intercalation of solvents, allowing reversible lithium intercalation and de-intercalation at a graphite electrode. Besides, the severe polysulfides shuttle is also suppressed by the concentrated ether-based solutions. Consequently, the assembled graphite-sulfur full battery retains outstanding capacity of 686 mAh g(sulfur)(-1) at 0.1C rate after 105 cycles, along with high Coulombic efficiency. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords:Lithium-sulfur full batteries;Graphite electrode;Superconcentrated ether electrolyte;Sulfur cathode;Cycle stability