Rational design of heterostructured bimetallic sulfides (CoS2/NC@VS4) with VS4 nanodots decorated on CoS2 dodecahedron for high-performance sodium and potassium ion batteries

Developing electrode materials with desirable electrochemical properties for sodium and potassium ion batteries remains a tremendous challenge. Herein, hetero-structured hybrids with VS4 nanodots decorated on CoS2/NC dodecahedron (CoS2/NC@VS4) have been successfully synthesized through employing a cobalt-based imidazolate framework (ZIF-67) as a template to prepare CoS2/NC inner core. Then VS4 nanodots was then grown on the surface of CoS2/NC by hydrothermal method to construct a heterostructure. This heterogeneous structure facilitates full contact with the electrolytes and shortens electrons and ions diffusion distance. Besides, the nitrogen-doped carbon framework derived from ZIF-67 promotes electron transport and gives a reliable shield to buffer the volume swelling during discharge and charge processes. Driving by the synergistic effect of bimetallic sulfides and the multiple valence states vanadium sulfide, CoS2/NC@VS4 exhibits outstanding rate capability and stable cycle performance as the anode for SIBs and PIBs, including a specific capacity of 307 mAh g(-1) at the current density of 1.0 A g(-1) after 700 cycles for SIBs and a capacity of 291.54 mAh g(-1) at the current density of 1.0 A g(-1) after 430 cycles in PIBs. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, hetero-structured hybrids CoS2/NC@VS4 were synthesized, which exhibited outstanding rate capability and stable cycle performance for sodium and potassium ion batteries due to the full contact with electrolytes and shortened diffusion distance of electrons and ions.