Mixed-Metal–Organic\nFramework with Effective\nLewis Acidic Sites for Sulfur Confinement in High-Performance Lithium–Sulfur\nBatteries

Abstract

The mixed-metal–organic framework\napproach and a representative\nzirconium–metalloporphyrin framework (MOF-525) have been developed\nto create novel sulfur hosts and Li–S batteries. The different\nlocal environments at the centers of the porphyrin moieties in a series\nof MMOFsMOF-525­(2H), MOF-525­(FeCl), and MOF-525­(Cu)have\nled to their different behaviors for the confinement of sulfur and\nthus Li–S batteries. The unique structure of MOF-525­(Cu) has\nenabled each Cu²⁺ site to offer two Lewis acidic sites,\nfeaturing it as a very powerful MOF host for the inclusion of sulfur\nand polysulfides. The S@MOF-525­(Cu) cathode has demonstrated the best\nperformance among all reported sulfur/MOFs composite cathode materials,\nwith a reversible capacity of about 700 mAh/g at 0.5 C after 200 cycles.