An ultralight electroconductive metal-organic framework membrane for multistep catalytic conversion and molecular sieving in lithium-sulfur batteries

Abstract

Developing optimal catalysts, with the ability for trapping lithium polysulfides (LiPSs), catalyzing the multistep redox reaction concerning multifarious LiPSs and transferring electrons simultaneously, is vital for overcoming the shuttle effect in lithium-sulfur batteries (LSBs), which however remains a great challenge. Herein, the concept of effectively catalyzing multistep LiPSs conversion with one catalyst was demonstrated by integrating dual catalytic centers (Ni-N4 and quinone) within one metal-organic framework (MOF, Ni-TABQ). Moreover, an ultrathin and ultralight multifunctional electroconductive Ni-TABQ membrane (1.8 μm, 0.075 mg cm−2) were designed and in situ synthesized for tackling shuttle effect. Systematic in/ex situ electrochemical experiments and simulated calculations demonstrate that such MOF membrane enables ions sieving, LiPSs adsorption and multistep catalytic conversion at the same time. The LSB assembled with Ni-TABQ interlayer delivers a high capacity and ultra-low decay rate of 0.198‰ after 1000 cycles at 1 C, a capacity up to 5.59 mAh cm−2 after 100 cycles under high sulfur loading and lean electrolyte, as well as remarkably improved punch cell performances.