Hierarchical CoS@MoS2 core-shell nanowire arrays as free-standing electrodes for high-performance asymmetric supercapacitors

Abstract

The freestanding hierarchical core-shell nanoarchitectures exemplify the substantial interest in the development of next-generation electrode materials for energy storage systems . Herein, the hierarchical 3D CoS@MoS2 nanowire arrays (NWAs) are synthesized through a cost-effective hydrothermal process and followed by an effective sulfurization. The structural and morphological investigations of hierarchical 3D CoS@MoS2 NWAs are carried out for each stage. The 3D CoS@MoS2 NWAs yields a high specific capacity of 374.75 mA h g−1 and an areal capacity of 1.39 mA h cm−2 at a current density of 4 mA cm−2, exceptional rate capability (∼70.1% retention of the capacity at 20 mA cm−2), and remarkable cycling performance (∼96.2% retention of the capacity after 10,000 consecutive charge-discharge cycles), which are superior to the corresponding CoS nanowires and MoS2 nanosheets counterparts. The assembled CoS@MoS2//Fe2O3@rGO asymmetric supercapacitor (ASC) exhibits a broader working potential window of 1.7 V, ultrahigh energy density of 95.7 W h Kg−1 at the power density of 711.2 W kg−1, and super-long cycling stability (∼95.5% retention of capacity after 10,000 cycles), demonstrating that the hierarchical 3D CoS@MoS2 NWAs are promising as potential candidates for hig-performance SCs.