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

This work reports the rational design of MnO(x) nanorods on 3D crushed reduced graphene oxide (MnO(x)/C-rGO) by chemical reduction of Ni-incorporated graphene oxide (GO) followed by chemical etching to remove Ni. The resulting MnO(x)/C-rGO composite synergistically integrates the electronic properties and geometry structure of MnO(x) and 3D C-rGO. As a result, MnO(x)/C-rGO shows a significantly higher specific capacitance (C(sp)) of 863 F g(−1) than MnO(x)/2D graphene sheets (MnO(x)/S-rGO) (373 F g(−1)) and MnO(x) (200 F g(−1)) at a current density of 0.2 A g(−1). Furthermore, when assembled into symmetric supercapacitors, the MnO(x)/C-rGO-based device delivers a higher C(sp) (288 F g(−1)) than MnO(x)/S-rGO-based device (75 F g(−1)) at a current density of 0.3 A g(−1). The superior capacitive performance of the MnO(x)/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(x)/C-rGO. In addition, the MnO(x)/C-rGO-based device exhibits an energy density of 23 Wh kg(−1) at a power density of 113 Wkg(−1), and long-term cycling stability, demonstrating its promising potential for practical application. GRAPHICAL ABSTRACT: [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40580-022-00300-2.