Heterostructure Coupling Yolk-Shelled Nanosphere for CoSe/C@NC@MoSe₂/N,P-C Toward Efficient Sodium/Potassium Storage

In this study, based on the component regulation, dual engineering of heterostructure and architecture is developed to construct a yolk-shelled structure with a core of CoSe anchoring in carbon matrix and double shells of N-doped carbon and MoSe₂ in N,P-doped carbon (CoSe/C@NC@MoSe₂/N,P-C, CMSC). The yolk-shell structure with a void in the nanosphere can tolerate mechanical stress during the Na⁺/K⁺ storage and shorten their diffusion path. Besides, the heterostructure between the CoSe and MoSe₂ induces the built-in electric field and reduces the adsorption energy of the Na⁺/K⁺. This can boost the reaction kinetics and enhance the cycling stability for sodium/potassium ion batteries (SIBs/PIBs). As an anode material, a capacity of 262.3 mAh g^-1 is retained after 5000 cycles at 20.0 A g^-1 for the SIBs, while it is also demonstrated to have stable capacities of 171.3 mAh g^-1 under current of 5.0 A g^-1 for 500 cycles for the PIBs. Moreover, in the full cells of CMSC//Na₃V₂(PO₄)₃ and CMSC//FePBA, high energy densities of 263.9 Wh kg^-1 at 215.5 W kg^-1 and 147.7 Wh kg^-1 at 194.4 W kg^-1 are produced, respectively. The superior electrochemical performance illustrates its promising application in practice for the CMSC anode in SIBs/PIBs.