Enhancing the cycling stability of Li-S batteries with flexible freestanding sulfur cathodes through a spider-hunting strategy

Abstract

Flexible, high-capacity, and long-lasting freestanding sulfur cathodes are essential for developing advanced lithium-sulfur (Li-S) batteries in next-generation flexible electronic devices. However, the severe shuttle effect of lithium polysulfides (LiPSs) hinders their potential applications. This work introduces a flexible freestanding MX-CPNTs-CNTs@NS cathode for Li-S batteries by utilizing a spider-hunting strategy. In this strategy, carbonized polypyrrole nanotubes (CPNTs) and carbon nanotubes (CNTs) intertwine to form a 3D flexible and conductive spiderweb-like skeleton. The incorporation of MXene nanosheets as a function of spiders enables the regulation of a rich hierarchical porous structure. Additionally, the polar terminal functional groups of MXene nanosheets and the pyridinic N of CPNTs contribute to the chemical adsorption and electrocatalysis of LiPSs. The synergistic effect of physical and chemical inhibition strategies results in stable electrochemical performance, including a high specific capacity of 1203.2 mAh/g at 0.1C, and extended cycling stability of 739.6 mAh/g at 1C after 500 cycles (low decay rate of 0.036%). The excellent flexibility, specific capacity, and cycling stability make the freestanding MX-CPNTs-CNTs@NS cathode promising for high-performance flexible electronic devices.