VO2(B) nanobelts/reduced graphene oxide composites for high-performance flexible all-solid-state supercapacitors

Weifeng Lv,Ruifeng Zhao,Rong Wang,Ge Meng,Can Yang,Junfeng Liu,Aijuan Han

doi:10.1038/s41598-019-47266-6

Weifeng Lv, Ruifeng Zhao + Show 5 more

Open Access

https://doi.org/10.1038/s41598-019-47266-6

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Abstract

Vanadium oxide has attracted extensive attention for electrochemical capacitors due to its wide range of versatility. However, due to the relative poor conductivity and chemical stability of vanadium oxide, severe losses of capacitance often occur during charge and discharge processes. Herein, a free-standing vanadium dioxide (VO2(B)) nanobelts/reduced graphene oxide (VO2/rGO) composite film was fabricated by assembly of VO2(B) nanobelts and rGO for supercapacitors. The flexible rGO sheets and VO2(B) nanobelts intertwined together to form a porous framework, which delivered a 353 F g−1 specific capacitance at 1 A g−1, and after 500 cycles, the specific capacitance retention rate was 80% due to the enhanced conductivity of the VO2(B) nanobelts by rGO and increased transport of ions and electrons by the porous structures. An all-solid-state symmetrical supercapacitor was assembled from the VO2/rGO composites, which exhibited good energy storage performance with a maximum voltage of 1.6 V. The maximum power density is 7152 W kg−1 at the energy density of 3.13 W h kg−1, ranking as one of the highest power densities for reported materials. In addition, after 10000 cycles, it still has a specific capacitance retention rate of 78% at 10 A g−1.

Highlights

In recent years, the energy crisis caused by the rapid consumption of fossil energy has stimulated people to continuously explore renewable energy and new types of energy storage devices[1]
The morphologies of VO2(B) nanobelts, graphene oxide (GO), and VO2(B) nanobelts/reduced graphene oxide (VO2/rGO) composites were characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM) and shown in Fig. 1 and S1
The synthesized GO were ultrathin and nearly transparent, with some wrinkles seen from its TEM image (Fig. 1b)

Summary

Introduction

The energy crisis caused by the rapid consumption of fossil energy has stimulated people to continuously explore renewable energy and new types of energy storage devices[1]. 1D VO2(B) nanostructures are semimetal material with great flexibility and large surface area, which make them intertwine to paper-like film with little amount of binders in the fabrication of flexible electrodes and promising in ultra-thin flexible devices[21,22,23]. It adds an additional advantage in preventing breakage of the electrode frame due to mechanical bending/twisting of the flexible device. We fabricated a free-standing VO2(B) nanobelts/reduced graphene oxide (VO2/rGO) composite film by assembly of rGO and thin vanadium dioxide (VO2(B)) nanobelts As expected, it exhibited superior capacitance of 353 F g−1 at 1 A g−1. The device has the advantages of large energy density and high power density, and has broad application prospects in flexible energy storage devices

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