Designed Construction of Hierarchical CuCo 2 S 4 @Co(OH) 2 Core‐Shell Nanoarrays as Electrode Materials for High‐Performance Supercapacitors

Abstract In this paper, a novel three‐dimensional (3D) hierarchical structure of CuCo 2 S 4 @Co(OH) 2 core‐shell hybrid electrode was reported. It uses self‐supporting nanoneedles CuCo 2 S 4 without organic binders synthesized by hydrothermal method as ideal conductive supports for Co(OH) 2 nanosheets. The prepared CuCo 2 S 4 @Co(OH) 2 composite electrode has good electrochemical performance with a specific capacitance of 2066 F⋅g −1 at 1 A⋅g −1 (highest specific capacity of 258 mAh⋅g −1 ) and a high capacitance retention rate (over 82.76% at 10 A⋅g −1 after 1000 cycles). The asymmetric supercapacitor device (CuCo 2 S 4 @Co(OH) 2 //AC) has an energy density of 37.58 Wh⋅kg −1 at 795.8 W⋅kg −1 , and a high capacitance retention rate over 84.10% after 5000 cycles at 10 A⋅g −1 , which exhibits the enormous potential of this hybrid nanostructure as high performance supercapacitor electrode material.