3D porous graphene/NiCo2O4 hybrid film as an advanced electrode for supercapacitors

Graphene, as a family of 2D materials , can be used as film electrodes in energy storage devices because of its high surface area, electrical conductivity , and environmental stability. However, the pure graphene electrode attains aggregating nature, which significantly limits its practical application. To solve the overstacking problems, we construct a 3D porous reduced graphene (rGN) film by a novel and green Cu 2 O template-assisted route based on “coordinating etching and precipitating” process. Noticeably, a brand new material-NiCo 2 O 4 is generated when the template is removed by optimizing the coordinating etchant and the reaction conditions. It is observed that NiCo 2 O 4 perfectly imitates the shape of Cu 2 O template and has a hollow hydrangea-like structure. Furthermore, these emerging hollow NiCo 2 O 4 hydrangeas not only prevent the re-accumulation of sheet layers, but also afford 3D porous structure for film, and greatly enhance the energy storage properties on account of the pseudocapacitance of NiCo 2 O 4 . The 3D graphene/NiCo 2 O 4 film (3D rGN/NiCo 2 O 4 ) exhibits high specific capacity of 708.36 F g −1 at 1 A g −1 , remarkable rate performance of 582.11 F g −1 even at 16 A g −1 , and superior circulation ability with 94.3% capacitance retention after 6000 cycles at 10 A g −1 , indicating the potential applications in energy storage.