Abstract
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.