Construction of Free-Standing N-doped carbonaceous interlayers encapsulated with Co nanoparticles for Lithium–Sulfur batteries

Lithium sulfur (Li–S) batteries are suffered from the polysulfide shuttling and the sluggish redox kinetics of sulfur, impacting on their commercialization. In this work, free-standing carbonaceous materials anchored with N-doped carbon nanotubes embedded with Co nanoparticles (NCN-Co) were synthesized through the carbonization of non-woven fabrics and used as interlayers for Li-S batteries. The NCN-Co interlayers could provide plenty of active chemisorption sites and storage space for the adsorption and catalytic transformation of polysulfides. The free-standing hierarchical structure could act as a physical barrier of polysulfides. N-doping together with the encapsulated Co nanoparticles could improve the catalytic activities, enhancing the redox kinetics of polysulfides. Benefiting from the synergistic effect of the NCN-Co interlayers, the electrochemical performance of Li-S batteries was significantly improved. An initial discharge specific capacity of 1092 mAh g−1 was achieved at 2C and high-capacity retention rate was demonstrated even after discharged/charged for over 600 cycles. This work provides a promising route for the preparation of interlayer materials for Li-S batteries.