Deposition Mode Design of Li₂S: Transmitted Orbital Overlap Strategy in Highly Stable Lithium‐Sulfur Battery

Abstract

Serious lithium polysulfides (LiPSs) shuttle effect and slow kinetic process lead to poor cycle performance and low working efficiency of lithium‐sulfur battery (Li‐S battery), which limits its commercialization. In this paper, a composite frame with transmitted orbital overlap is proposed as the functionalized separator of Li‐S battery (MX@WSSe/PP). It consists of WSSe nanosheets and MXenes nanosheets (MX). The experiments and theoretical calculations both show that MX@WSSe/PP can not only inhibit the LiPSs shuttle effect to realize the effective utilization of cathode materials, but also enhance the overall reversibility and reaction kinetics of the device by transforming the 2D deposition mode of Li2S into 3D mode. The transformation of Li2S deposition mode comes from the changed local charge density on MX@WSSe composite surface, which regulates the filling state of electron orbits and affects the orbital overlap between different atoms. This effect can even be transmitted to Li2S molecules far from the surface of MX@WSSe. The capacity decay per cycle of Li‐S battery with MX@WSSe/PP is only 0.016% in 1000 cycles at 2 C. Also, a high area capacity of 9.39 mAh cm−2 is achieved at high sulfur loading (10.2 mg cm−2) and low electrolyte/sulfur ratio (7.5 µL mg−1).

Formation of 2D Amorphous Lithium Sulfide Enabled by Mo2C Clusters Loaded Carbon Scaffold for High‐Performance Lithium Sulfur Batteries

“…The promising alternative, lithium-sulfur (Li-S) battery, utilizes sulfur as the active material and offers a high theoretical capacity of 1675 mAh g −1 and attractive energy density of 2600 Wh kg −1 , [1][2][3] enabled by the reversible conversion reaction between sulfur and lithium sulfide through a sequence of lithium polysulfide intermediates (LiPSs). However, the commercialization of Li-S batteries has encountered significant hurdles, including the insulating nature of sulfur and lithium sulfide, significant volumetric expansion (≈80%), and the notorious shuttling effect of LiPSs.…”