Hierarchical construction of Co3S4 nanosheet coated by 2D multi-layer MoS2 as an electrode for high performance supercapacitor

Two-dimensional materials with multi-layer hierarchical structures are generally accepted to be able to provide more active sites and shorter electrolyte diffusion channels, which are highly desired for application in supercapacitors. Nonetheless, their uncontrollability and inaccurate phase composition of elaborate nanostructures remain a major technological hurdle. To address the issue, an exquisite layered structure of Co3S4 nanosheet coated by 2D multi-layer MoS2 (Co3S4@MoS2) is constructed through one-step sulfidation, using carbonized leaf-like Co-ZIF (Co-ZIF-L) nanosheet arrays as a precursor. The carbon skeleton formed by carbonization of Co-ZIF-L effectively prevents structural collapse, especially to ensures the cycle stability. Meanwhile, the nanosheet arrays reduces the agglomeration and promotes the multi-layer 2D MoS2 simultaneously. The as-prepared Co3S4@MoS2 exhibits an appreciable specific capacity (576 C g−1 at 1 A g−1). The Co3S4@MoS2// reduced graphene oxide (RGO) asymmetric supercapacitor shows an energy density of 53.96 Wh kg−1 at a power density of 887.01 W kg−1, and outstanding cycle life with the 94.5% of capacity retention after 10,000 cycles. Such excellent performance is attributed to the rational structure, and the multi-layer 2D MoS2 improves the reaction kinetics of the electrode. The strategy presented here offers promising opportunities in improving electrode performance of energy storage devices.