β‐Cyclodextrin Anchor NiCo2S4 on Graphene to Enhance Electrochemical Performance of Supercapacitor

To construct high–energy‐density supercapacitors, an electrode material with high conductivity needs to be compounded with an electrode material with high capacitive properties. Herein, NiCo 2 S 4 ‐β‐cyclodextrin graphene (CDG) composite material formed by growing NiCo 2 S 4 nanoparticles on graphene oxide (GO) modified with β‐Cyclodextrin (β‐CD) is reported. The modification of β‐CD can tackle the problem of agglomeration of GO and acts as a bridge to increase the binding force between NiCo 2 S 4 nanoparticles and substrates. Combining the benefits of the modified GO and NiCo 2 S 4 , the synthesized composite electrode exhibits excellent electrochemical properties of 1325.9 F g −1 at 1 A g −1 and rate capability of 55.5% as current density increases from 1 to 7 A g −1 . Moreover, the asymmetric device, fabricated with NiCo 2 S 4 ‐β‐CDG as the positive electrode and active carbon as the negative electrode, exhibits a maximum energy of 30.72 Wh kg −1 at 1.28 kW kg −1 power density.