Simultaneously in-situ fabrication of lithium fluoride and sulfide enriched artificial solid electrolyte interface facilitates high stable lithium metal anode

Abstract

Lithium (Li) metal has to overcome key performance flaws before it can be used as the anode material for the next generation Li+ batteries. One of its major issues is Li dendrite growth and detachment, which causes safety issues and low Coulombic efficiency for Li metal batteries. Constructing a stable solid electrolyte interface (SEI) is considered to be the most straightforward solution to the Li anode interface defects. Here, we develop a facile stratagem of 2-(Fluorosulphonyl)difluoroacetic acid-treated Li foil to obtain a Li metal anode coated by the lithium fluoride and sulfide enriched composite layer (LiF/sulfide enriched Li). The experimental and theoretical simulations demonstrate that the ideal artificial SEI can induce uniform Li+ distribution at the interface and effectively inhibit dendrite growth. As results, the LiF/sulfide enriched Li symmetrical cells exhibit excellent cycling stability and low Li deposition overpotential, which maintain a low overpotential of ∼ 10 mV for over 1000 h at 1 mA cm−2 in an ether electrolyte of DME/DOL + LiTFSI and steadily cycles for 350 h in a carbonate electrolyte of EC/EMC + LiPF6. Furthermore, full cells assembled with NCM811 and sulfur cathode exhibit enhanced cyclability. This facile and controllable stratagem provides a more practical possibility for modifying the Li metal anode.