Regulated lithium deposition behavior by chlorinated hybrid solid-electrolyte-interphase for stable lithium metal anode

Abstract

Lithium (Li) metal is the ultimate anode material for use in next-generation batteries in the pursuit of higher energy densities. However, the traditional solid electrolyte interphase (SEI) owns the disadvantages of large interfacial impedance, low Li ions migration rate and easy fragility. Herein, this is the first report that reveals in detail the rationality of Li deposition beneath the chlorinated hybrid layer and fast ion transport kinetics at LiCl/Li interface through density functional theory (DFT) estimation. Based on this, an artificial SEI layer enriched with LiCl, LiZn alloy and in-situ ring-opening polymerization of poly(tetrahydrofuran) (PTMG) is constructed on lithium metal surface. The glow-discharge optical emission spectroscopy (GD-OES) results revealed that LiCl is mainly enriched on the surface of the artificial SEI, its excellent electron-blocking ability could inhibit the electron flow tunneling from the Li metal to SEI, which prevents the generation of Li0. As expected, the Li metal anode with an artificial chlorinated hybrid SEI layer exhibits excellent cycle performance over 2000 h with lower overpotential of 11 mV at 1 mA cm−2. Moreover, full-cell delivers higher capacity retention and coulombic efficiency after long cycles under high LiFePO4 loading (at 17.4 mg cm−2, 3.0 mAh cm−2).