A MOF-mediated strategy for constructing human backbone-like CoMoS₃@N-doped carbon nanostructures with multiple voids as a superior anode for sodium-ion batteries

Nanostructured, multicomponent metal sulfides have recently attracted much attention as anode materials for high-performance sodium ion batteries (SIBs). Therefore, a simple strategy for constructing rationally designed multicomponent metal sulfide-based nanostructures is needed. Herein, we propose a metal-organic framework-based (MOF) strategy to construct human backbone-like CoMoS₃ nanostructures with multiple voids as high-performance SIB anodes. This strategy involves conformal coating of a Co-based MOF onto the surface of MoO₃ nanobelts, followed by sulfidation of the hybrids. We explore not only the optimized conditions for uniform ZIF-67 coating on the MoO₃ nanobelts, but also the transformation mechanism of the MoO₃@ZIF-67 hybrids into CoMoS₃ nanobackbones with multiple voids. To further improve the structural stability, the nanobackbones were coated with polydopamine and then thermally treated under inert conditions, resulting in the formation of CoMoS₃@N-doped carbon (NC) nanobackbones. Benefiting from their unique structural design, conductive carbon shells, and synergistic effects between multiple components, the CoMoS₃@NC nanobackbones exhibit enhanced electrochemical performance when tested as anode materials for SIBs. They deliver a reversible capacity of 411 mA h g^-1 for 300 cycles at a current density of 2 A g^-1, and an excellent rate performance of 349 mA h g^-1 at a current density of 10 A g^-1. This simple strategy can be used to fabricate other multicomponent metal sulfide/carbon composites with multiple voids, which can be used for various applications.