Design of electrode materials of nickel-cobalt compounds for aqueous symmetrical supercapacitor with large power and high energy density

Abstract

A porous cobalt-nickel material was designed based on using metal element to build framework and achieving porosity by room temperature sulfuration. Therefore, a variety of hydrothermal reaction experiments were carried out, and it is very interesting to obtain a series of products of Nickel-cobalt compounds with different shapes, including hexagonal, nanowire arrays, irregular block and urchin-like structure etc. It was observed that the phase state of cobalt-nickel compounds could change from the conventional continuous solid phase to porous phase of micro/nanostructure via sulfuration. Especially, as an electrode, the obtained porous material, honeycomb-inspired nickel cobalt sulfides, delivered a specific capacity of 1020 F/g at a high current density of 30 A/g, and an aqueous symmetrical supercapacitor with the electrode delivered a maximum energy density of 68 Wh/kg, a high power density of 7999 W/kg at 28 Wh/kg, and lighted a red LED for more than 60 s, showing excellent electrochemical property.