A metal-organic framework-based electrocatalytic membrane boosts redox kinetics of lithium-sulfur batteries

The shuttle behavior and sluggish conversion kinetics of polysulfides significantly impede the commercialization of lithium-sulfur (Li-S) batteries. Herein, we report a membrane-based electrocatalytic interlayer that consists of metal-organic framework (MOF) Co-ZIF-9 sheets and carbon nanotubes (CNT) for these issues, which is facilely weaved by vacuum filtration. The fully exposed active sites of ZIF-9 sheets endow this interlayer an efficient anchoring ability towards polysulfides, therefore efficaciously suppressing the polysulfides shuttle, and, more importantly, a strong electrocatalytic effect to accelerate the redox kinetics. Meanwhile, the threedimensional cross-linked network structured by the conductive CNT and MOF material favours a rapid ion and electron transport, and the full utilization of adsorption and catalytic sites. As a consequence, this interlayer exhibits an excellent rate performance (a capacity up to 817 mAh g-1 under 5 C), an exceptional cyclic stability (a tiny decay of 0.019% for 1000 cycles at 1 C) and a distinctive high-sulfur loading performance (7.2 mg cm-2) under a reduced electrolyte content. This study provides inspirations for the rational design of MOF-based nanostructures that can validly anchor polysulfides and catalyze their conversion for high-powered Li-S batteries.