Hierarchical nMOF-867/MXene Nanocomposite for Chemical Adsorption of Polysulfides in Lithium-Sulfur Batteries

Lithium-sulfur battery, a promising candidate for rechargeable battery, has aroused wide attention since the traits of high theoretical energy density and low cost. Nevertheless, issues of poor conductivity, severe volume change during cycling, and particular deleterious shuttle effects impede the commercialization of lithium-sulfur batteries. Herein, a convenient and scalable method via electrostatic self-assembly and in situ solvothermal strategies is employed to prepare three-dimensional hierarchical nMOF-867/Ti3C2Tx. In this advantageous heterostructure, nMOF-867 with rich porosity not only provides the accommodation of sulfur but also enables chemical binding of polysulfides through stable double bonds (Li-N and Zr-S bond), while the distribution of nMOF-867 on the highly conductive Ti3C2Tx would promote redox conversion kinetics of adsorbed polysulfides. Furthermore, structurally stable nMOF-867/Ti3C2Tx can serve as a buffer to reduce the volume expansion during the charge/discharge process. Hence, nMOF-867/Ti3C2Tx, the sulfur host of lithium-sulfur batteries, exhibits a high reversible capacity of 1302 mAh g(-1) at 0.2 C and a remarkable rate capability of 581 mAh g(-1) at 4 C. Impressively, a high initial capacity of 801 mAh g(-1) can be retained at 1 C, with the slight capacity fading rate of 0.054% per cycle over 1000 charge/discharge cycles. This work provides the inspiration to generally fabricate the well-designed MXene-based nanocomposites for lithium-sulfur batteries with good performance.

Automated summary

In this study, a convenient and scalable method was employed to prepare three-dimensional hierarchical nMOF-867/Ti3C2Tx, which addresses the issues of poor conductivity, severe volume change, and shuttle effects in lithium-sulfur batteries, thus enhancing the performance and cycling life of the batteries.