All MOF-derived-carbon material-based integrated electrode constructed by carbon nanosheet sulfur host and Fe microparticles with carbon nanofiber network interlayer for lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries are promising future-generation portable electronic devices due to the outstanding energy density of S. However, the serve problems of Li–S batteries originating from the intrinsic poor conductivity of S and the dissolution and diffusion of dissoluble polysulfides in electrolytes are a major limitation. Herein, we demonstrated an all metal–organic framework (MOF)-derived carbon material-based integrated sulfur cathode, which was constructed with 3D carbon nanofiber network with Fe microparticles (MIL1000) as interlayer on a polypropylene (PP) separator and 2D nanosheets (MIL900-H) as S host. Notably, the MIL900-H carbon nanosheets with many mesopores and doping oxygen possessed lithium-ion pathways and chemical adsorption of soluble polysulfides, and the MIL1000 interlayer could chemically adsorb, physically block polysulfide, and facilitate the kinetics of the cathode reaction. As a result, the integrated electrode that avoided the use of a metal current collector exhibited a high initial capacity of 1244.6 mAh/g at 0.1 C, fast Li2S nucleation, and excellent cycle stability with the capacity retention of 69.3% after 500 cycles at 1 C. Therefore, this rationale strategy of constructing an all MOF-derived-carbon material-based integrated electrode can be extended to other abundant MOF-derived materials for high energy density Li–S batteries.