Binder-Free\nHierarchical Urchin-like Manganese–Cobalt\nSelenide with High Electrochemical Energy Storage Performance

Abstract

Transition\nmetal selenides are widely considered as good electron\nconductor materials, showing bright prospect in energy storage and\nconversion. However, binary metal selenides as supercapacitor electrode\nmaterials are rarely reported. Herein, a simple and binder-free hydrothermal\nmethod is employed to grow hierarchical urchin-like MnCo-selenide\non nickel foam. The unique hierarchical microstructure, synergetic\neffect, and excellent conductivity enable the electrode exhibit outstanding\nsupercapacitor performance compared with counterpart oxide and sulfide,\nincluding high specific capacitance (1656 F g^–1 at\n1 A g^–1) and extraordinary cycle performance (8.2%\ncapacity decline after 8000 cycles). Additionally, the asymmetric\nsupercapacitor (ASC), employing MnCo-selenide and AC as anode and\ncathode, exhibits remarkable energy density of 55.1 Wh kg^–1 at 880 W kg^–1, confirming the as-prepared urchin-like\nMnCo-selenide is a satisfactory material for the energy storage system.