The additive-free electrode based on the layered MnO2 nanoflowers/reduced, graphene oxide film for high performance supercapacitor

Abstract

The MnO2 nanoflowers/reduced graphene oxide composite is coated on a nickel foam substrate (denoted as MnO2 NF/RGO @ Ni foam) via the layer by layer (LBL) self-assembly technology without any polymer additive, following the soft chemical reduction. The layered MnO2 NF/RGO composite is uniformly anchored on the Ni foam skeleton to form the 3D porous framework, and the interlayers have access to lots of ions channels to improve the electron transfer and diffusion. This special construction of 3D porous structure is beneficial to the enhancement of electrochemical property. The specific capacitance is up to 246Fg−1 under the current density of 0.5Ag−1. After 1000 cycles, it can retain about 93%, exhibiting excellent cycle stability. The electrochemical impedance spectroscopy measurements confirm that MnO2 NF/RGO @ Ni foam electrode has lower RESR and RCT values when compared to MnO2 @ Ni foam and RGO @ Ni foam. This study opens a new door to the preparation of composite electrodes for high performance supercapacitor.