Defects Engineering of Lightweight Metal–Organic Frameworks-Based Electrocatalytic Membrane for High-Loading Lithium–Sulfur Batteries

Abstract

The sluggish kinetics and shuttle effect of lithium polysulfide intermediates are the major issues that retard the practical applications of lithium–sulfur (Li–S) batteries. Herein, we introduce a defect engineering strategy to construct a defected-UiO-66-NH2-4/graphene electrocatalytic membrane (D-UiO-66-NH2-4/G EM) which could accelerate the conversion of lithium polysulfides in high sulfur loadings and low electrolyte/sulfur (E/S) ratio Li–S batteries. Metal–organic frameworks (UiO-66-NH2) can be directionally chemical engraved to form concave octahedra with abundant defects. According to electrocatalytic kinetics and DFT calculations studies, the D-UiO-66-NH2-4 architecture effectively provides ample sites to capture polysulfides via strong chemical affinity and effectively delivers electrocatalytic activity of polysulfide conversion. As a result, a Li–S battery with such an electrocatalytic membrane delivers a high capacity of 12.3 mAh cm–2 (1013 mAh g–1) at a sulfur loading up to 12.2 mg·S cm–2 under a lean electrolyte condition (E/S = 5 μL mg–1-sulfur) at 2.1 mA cm–2 (0.1 C). Moreover, a prototype soft package battery also exhibits excellent cycling stability with a maintained capacity of 996 mAh g–1 upon 100 cycles.

Enhanced Polysulfide Conversion with Highly Conductive and Electrocatalytic Iodine‐Doped Bismuth Selenide Nanosheets in Lithium–Sulfur Batteries

“…[ 31–36 ] However, cathodes based on metal sulfides are generally characterized by moderate electrical conductivities, limited sulfur utilization, insufficient cycling stability, and low rate capabilities. [ 37–41 ]…”

Function-directed design of battery separators based on microporous polyolefin membranes

“…[91][92][93] For example, Zhang et al prepared a MOF/graphene-coated PP separator for high-loading Li-S batteries using an automatic doctor blade. 94 The thickness of the MOF/graphene coating (6-30 mm) determined the capacity, cycling stability and rate performance of the Li-S battery and could be tuned by the automatic doctor blade.…”

Versatile Asymmetric Separator with Dendrite‐Free Alloy Anode Enables High‐Performance Li–S Batteries

“…[8,9] Therefore, for tackling the "shuttle effect" of soluble polysulfides, numerous works have contributed to immobilizing the polysulfides via interlayer on separators in LSBs. The interlayer can be composed by carbonaceous materials, [10][11][12] metalbased materials, [13][14][15] metal organic frameworks, [16,17] covalent organic frameworks, [18,19] and so on. However, unlike molecular LiPSs, the polysulfides (PSs) anions are a kind of Lewis base that cannot be entirely trapped by the above materials.…”