Hierarchical\nCoS₂/N-Doped Carbon@MoS₂ Nanosheets with Enhanced\nSodium Storage Performance

Abstract

We\nintroduce a hierarchical nanostructure of CoS₂/N-doped\ncarbon@MoS₂ comprising two transition-metal sulfides CoS₂ and MoS₂, with enhanced sodium storage performance\nin sodium-ion batteries. A micron-sized Co metal–organic framework\n(MOF) is transformed into a CoS₂/N-doped carbon composite,\nfollowed by a solvothermal growth of MoS₂ nanosheets on\nthe surface. The resulting composite material offers several specific\nadvantages for sodium storage: (i) accelerated sodium-ion diffusion\nkinetics due to its heterogeneous interface; (ii) shortened ion diffusion\npath and exposed active sites for sodium storage due to its hierarchical\nnanosheet architecture; and (iii) homogeneous nitrogen doping of the\nMOF-derived carbon, which is beneficial for electronic conductivity.\nDue to these merits, this composite exhibits excellent electrochemical\nperformance with a specific capacity of 596 mAh g^–1 after 100 cycles at 0.1 A g^–1 and 395 mAh g^–1 at 5.0 A g^–1.