LAUSR

Lithium sulfur (Li-S) batteries have been considered as one of the most promising next-generation rechargeable batteries owing to its high energy density and cost-effectiveness. However, the sluggish kinetics of the sulfur reduction reaction process, which is so far insufficiently explored, still impedes its practical application. Metal organic frameworks (MOF) are widely investigated as sulfur immobilizer, but the interactions and catalytic activity of lithium polysulfides (LiPs) on metal nodes are weak due to the presence of organic ligands. Herein, we present a strategy to design Quasi-MOF nanospheres, which has a transition-state structure between MOF and metal oxide, via controlled ligand exchange strategy to serve as sulfur electrocatalyst. The Quasi-MOF not only inherits the porous structure of MOF, but also exposes abundant metal nodes to act as active sites, rendering strong LiPs absorbability. The reversible deligandation/ligandation of Quasi-MOF and its impact on the durability of catalyst over the course of electrochemical process has been acknowledged, which confers a remarkable catalytic activity. Attributed to these structural advantages, Quasi-MOF delivers a decent discharge capacity and low capacity fading rate over long-term cycling. This work not only offers insight into the rational design of Quasi-MOF based composite, but also provides guidance for the application in Li-S batteries. This article is protected by copyright. All rights reserved.