3D hierarchical NiCo2S4/Ni–Co LDH architecture for high-performance supercapacitor

Supercapacitor is one kind of alternative energy storage devices. Constructing three-dimensional (3D) porous heterogeneous composite electrode materials is an important method to improve the performance of supercapacitor. Herein, we have used a simple solvothermal strategy to prepare NiCo2S4/Ni–Co LDH with a porous heterostructure grown on carbon fiber paper. The composite material is assembled from nanosheets into a 3D structure intertwined with each other. It possesses rich micro-pore size and exhibits excellent electrochemical properties. The unique structure favors for accelerating the electron transfer and electrolyte transport during the electrochemical process. At a current density of 10 mA cm−2, the specific capacitance is 1403 F g−1 (2.67 F cm2). When the current density is increased by 5 times, the specific capacitance is still as high as 1111 F g−1 (2.11 F cm2), showing good rate performance. Under a large current density of 30 mA cm−2, a long-term cycling performance of 5000 cycles has been evaluated. The capacitance retention reaches 111.1%, exhibiting outstanding cycle stability. Furthermore, the assembled symmetric supercapacitor device of also displays good electrochemical activities with an area capacitance of 0.19 F cm−2 at a current density of 3 mA cm−2, and superior cycling ability of high capacitance retention rate (115.4%) after 5000 cycles of charge and discharge process. The above results show that NiCo2S4/Ni–Co LDH is a promising candidate for high-performance supercapacitor.