Self-standing manganese dioxide/graphene carbon nanotubes film electrode for symmetric supercapacitor with high energy density and superior long cycling stability

Abstract

The low capacitance utilization and capacitance fading of manganese dioxide (MnO2) is mainly due to poor electro-conductivity and irreversible phase transform. This work proposes a new method of designing hierarchical and binder-free electrode based on MnO2 material for stable supercapacitor with high specific capacitance. Herein, we fabricated the self-standing electrode of MnO2 on nitrogen-doped graphene and single wall carbon nanotubes (SWCNTs) self-standing film (NGCF) by electrochemical deposition. As a result, as-prepared MnO2/NGCF cathode showed excellent electrochemical performance of 489.7 F g-1 at 1 A g-1. Assembled symmetric aqueous supercapacitor (SC) manifests high voltage of 2.4 V and presents excellent high energy density of 106.7 Wh kg-1 at 1200 W kg-1 and outstanding long-life stability without no decay after 10 000 charge-discharge circuits. This work proposes a new view of designing hierarchical and binder-free electrode with high energy density and long cycling stability based on MnO2 material for stable symmetric supercapacitor.