Highly oriented MIL-101(Cr) continuous films grown on carbon cloth as efficient polysulfide barrier for lithium-sulfur batteries

Abstract

The development of lithium-sulfur (Li-S) batteries is obstructed by polysulfide-shuttling and sluggish conversion kinetics during the process of charge and discharge. Herein, a highly oriented MIL-101(Cr) continuous film is developed on carbon cloth and utilized as trustworthy interlayer for lithium-sulfur batteries. This interlayer possesses a unique hierarchical porous structure and abundant active sites, providing efficient confinement of polysulfides through strong physical/chemical adsorption. Specially, the Lewis acidic Cr(III) centers of MIL-101(Cr) films are able to coordinate with polysulfides through Lewis acid-base interactions. Moreover, MIL-101(Cr) films also have the electrocatalytic effect of promoting the conversion of polysulfides. Benefiting from these features, this composite interlayer establishes an efficient barrier to inhibit the shuttling of polysulfides. Consequently, the as-prepared multifunctional interlayer exhibits a remarkable rate performance of 635 mAh g−1 at 3 C, a superior cycle stability with a low-capacity decay of 0.039% per cycle over 500 cycles at 1 C and high areal specific capacity of 4.3 mAh cm−2 under raised sulfur loading (5.1 mg cm−2).