Conductive metal-organic framework flowers facilitate the anchoring and conversion kinetics of polysulfides for lithium‑sulfur batteries

Abstract

Enhancing the trapping and catalytic conversion of polysulfides is the main path to restrain their shuttling for durable lithium‑sulfur batteries (LSBs). Herein, we report a flower-like metal-organic framework (MOF) MIL-47 layer as an interlayer material to achieve this purpose. The proposed MOF material possesses a unique flower-like structure that is composed of two-dimensional nanosheets, which is conducive to the mass transfer and the exposure of active sites, enabling an efficient adsorption towards polysulfides. Moreover, the high conductivity combined with sufficient catalytic active centers are instrumental in accelerating the redox processes of polysulfides conversion. Consequently, this flowery MOF-based interlayer endows LSBs an amazing capacity of 1003.6 mAh g−1 and an ultralong cycling stability with a low attenuation rate of 0.029 % over 1000 cycles under 1C, together with an exceptional rate performance (a capacity high as 696.9 mAh g−1 under 5C). In addition to this, an elevated sulfur loading and reduced electrolyte content do not affect its excellent cycling and rate performance. This work provides a new mentality to exploit multi-role nanostructured materials for LSBs.