One-step hydrothermal synthesis of sandwich-type NiCo 2 S 4 @reduced graphene oxide composite as active electrode material for supercapacitors

• DOI: 10.1016/j.apsusc.2017.07.016
• Publication Date: 2017-07-05T01:46:21Z
• Authors: Fangping Wang; Guifang Li; Qianqian Zhou; Jinfeng Zheng; Caixia Yang; Qizhao Wang
• Keywords: Power density; Hydrothermal Synthesis

Abstract A facile one step hydrothermal process is developed for the synthesis of NiCo 2 S 4 @reduced graphene oxide (NiCo 2 S 4 @RGO) composite as electrode for electrochemical supercapacitors. This NiCo 2 S 4 @RGO electrode exhibits an ultrahigh specific capacitance of 2003 F g −1 at 1 A g −1 and 1726 F g −1 at 20 A g −1 (86.0% capacitance retention from 1 A g −1 to 20 A g −1 ), excellent cycling stabilities (86.0% retention after 3500 cycles). Moreover, an asymmetric supercapacitor is successfully assembled by using NiCo 2 S 4 @RGO nanoparticle as the positive electrode and active carbon(AC) as the negative electrode in 2 M KOH electrolyte. The fabricated NiCo 2 S 4 @RGO//AC asymmetric supercapacitor exhibits a high energy density of 21.9 Wh kg −1 at a power density of 417.1 W kg −1 and still remains an impressive energy density of 13.5 Wh kg −1 at a large power density of 2700 W kg −1 . The results demonstrate that the NiCo 2 S 4 @RGO composite is a promising electrode material as supercapacitors in energy storage.