Two-dimensional hierarchical MoS2 lamella inserted in CoS2 flake as an advanced supercapacitor electrode

The two-dimensional hierarchical structure has a positive effect on improving the stability of the electrode materials for supercapacitors. In this work, an exquisite hierarchical structure of CoS2 flake with the twodimensional MoS2 lamella (MoS2@CoS2) was constructed using flake-like ZIF-67 as a precursor through multiple calcination and one-step sulfuration. The CoS2 nanosheets composed of CoS2 nanoparticles anchored on the carbon skeleton could provide a stable structure for subsequent reactions. Moreover, the inserted 2D cross-linked MoS2 multilayers could effectively prevent the interlayer expansion and structural collapse, and especially ensure the electrochemical performance and morphological stability of the transition metal sulfides. As a result, MoS2@CoS2 exhibits an extraordinary specific capacitance (950 F g(-1) at 1 A g(-1)) and an appreciable cycle life with a capacitance retention of 94.6% (10, 000 cycles at 10 A g(-1)). Meanwhile, the MoS2@CoS2//reduced graphene oxide (RGO) asymmetric supercapacitor shows an energy density of 33.94 Wh kg(-1) at a power density of 1040 W kg(-1). Such excellent performance benefits from more electrochemically active sites and the rapid kinetics reaction which was ascribed to the rational design of two-dimensional hierarchical structure.

Automated summary

A two-dimensional hierarchical structure was constructed with CoS2 flakes and MoS2 lamellas, improving the stability of electrode materials for supercapacitors and exhibiting excellent electrochemical performance and cycle life. The structure benefits from more electrochemically active sites and rapid kinetics reaction, attributed to the rational design of the two-dimensional hierarchical structure.