Wrapping ZIF-67 with vine-like carbon nanotubes to enhance the capture of polysulfide and consolidation of active site

Abstract

The shuttle effect of polysulfide and slow reaction kinetics has hindered the commercialization of lithium–sulfur batteries. Here, metal organic framework (MOF)-derived nitrogen-doped carbon was used as templates, and the continuous interspersed filamentary network structure of multi-walled carbon nanotubes (MWCNT) was used as a modifier to synthesize Co-NC@MWCNT. The exposure of Co-MOF with a high density of catalytic sites in the pores effectively improves the sulfur stability capacity of the composite and inhibits the shuttle effect. The outermost layer of coated MWCNTs and the intermediate layer of N-doped porous carbon effectively protected the Co2+ active site of the dodecahedral configuration from easy deactivation and agglomeration. The prepared Co-NC@MWCNT composite had an initial discharge capacity of 1240 mA h g−1 (0.1C), it maintained a low decay rate of 0.054 % after 1000 cycles (0.5C). The graphite-like layer gap and multilayer tube structure of the networked MWCNT can effectively mitigate volume expansion during charging and discharging and provide Li+ transport channels to improve electrical conductivity. Moreover, the energy storage devices developed as part of this work have excellent electrochemical properties and have a noteworthy industrial potential.