Boosting capacitive performance of manganese oxide nanorods by decorating with three-dimensional crushed graphene.

This work reports the rational design of MnO nanorods on 3D crushed reduced graphene oxide (MnO/C-rGO) by chemical reduction of Ni-incorporated graphene oxide (GO) followed by chemical etching to remove Ni. The resulting MnO/C-rGO composite synergistically integrates the electronic properties and geometry structure of MnO and 3D C-rGO. As a result, MnO/C-rGO shows a significantly higher specific capacitance (C) of 863 F g than MnO/2D graphene sheets (MnO/S-rGO) (373 F g) and MnO (200 F g) at a current density of 0.2 A g. Furthermore, when assembled into symmetric supercapacitors, the MnO/C-rGO-based device delivers a higher C (288 F g) than MnO/S-rGO-based device (75 F g) at a current density of 0.3 A g. The superior capacitive performance of the MnO/C-rGO-based symmetric device is attributed to the enlarged accessible surface, reduced lamellar stacking of graphene, and improved ionic transport provided by the 3D architecture of MnO/C-rGO. In addition, the MnO/C-rGO-based device exhibits an energy density of 23 Wh kg at a power density of 113 Wkg, and long-term cycling stability, demonstrating its promising potential for practical application.