The construction of molybdenum disulfide/cobalt selenide heterostructures @ N-doped carbon for stable and high-rate sodium storage

Constructing heterostructures is an important approach to develop high-performance anode materials for sodium ion batteries (SIBs). The abundant phase interfaces provide numerous defects and active sites for rapid electron/ion transport. Herein, CoSe₂ ⊂ NC@NC/MoS₂ heterostructures are prepared through a multi-step reaction strategy, CoSe₂ nanoparticles served as the coating shells for MoS₂ cores are anchored in carbon frameworks. The core–shell structure effectively buffers the double volume expansion and inhibits the dissolution of MoS₂ and CoSe₂ in the electrolyte. As SIBs anodes, the heterostructure delivers a high reversible capacity of 481.6 mAh g⁻¹ at 0.5 A g⁻¹ after 100 cycles, superior rate capability (174.5 mAh g⁻¹ at 20.0 A g⁻¹), excellent long-term cycle performance (333.4 mAh g⁻¹ after 2000 cycles at 5.0 A g⁻¹). The DFT calculation proves that the electronic distribution of heterostructures is reconstructed with enhanced conductivity. The kinetic analysis, mechanism characterizations and full-cells tests exhibit the synergistic reaction mechanism among different components and practical application prospects. The heterostructure also shows more rapid ions diffusion kinetics than single components.