Facile Synthesis of Ag‐Decorated Ni₃S₂ Nanosheets with 3D Bush Structure Grown on rGO and Its Application as Positive Electrode Material in Asymmetric Supercapacitor

Abstract

Abstract A facile and cost‐effective route is developed for synthesizing 3D bush structure of Ag nanoparticles‐decorated Ni 3 S 2 grown on reduced graphene oxide (rGO) for the first time. In this composite, Ni 3 S 2 exhibits nanosheet networks with porous feature. The electrochemical measurements display that the as‐prepared rGO/Ag/Ni 3 S 2 composite possesses a superior areal capacitance of 5920 mF cm −2 at current density of 5 mA cm −2 . 77.5% of the initial areal capacitance is retained as current density increased from 5 to 20 mA cm −2 . Encouragingly, this electrode exhibits excellent cycle performance with 94% capacitance retention after 3000 cycles at a current density of 30 mA cm −2 , whereas for rGO/Ni 3 S 2 composite electrode, only 84.7% of the initial value is maintained. The enhanced conductivity and unique structure of rGO/Ag/Ni 3 S 2 composite attribute to its superior electrochemical performance. In addition, an aqueous asymmetric supercapacitor is fabricated using rGO/Ag/Ni 3 S 2 composite as positive electrode and the nitrogen‐doped graphene as negative electrode. The assembled device delivers high energy density of 28.7 Wh kg −1 at a power density of 425 W kg −1 . This work may prompt the development and application of active materials decorated with highly conductive nanoparticles in supercapacitors.