Disodium citrate-assisted hydrothermal synthesis of V2O5 nanowires for high performance supercapacitors.

Shanshan Pan,Shuolin Han,Lin Wang,Guangjie Shao,Ling Chen,Yahao Li

doi:10.1039/c7ra12607g

Abstract

Orthorhombic vanadium pentoxide (V2O5) nanowires with uniform morphology were successfully fabricated via a facile hydrothermal process. The effect of disodium citrate dosage on the crystallinity, morphology and electrochemical properties of the products was analyzed. Experimental results indicate that orthorhombic V2O5 nanowires with high crystallinity and diameter of about 20 nm can be obtained at 180 °C for 24 h when the dosage of disodium citrate is 0.236 g. Furthermore, the prepared V2O5 nanowires demonstrate a high specific capacitance of 528.2 F g−1 at 0.5 A g−1 and capacitance retention of 85% after 1000 galvanostatic charge/discharge cycles at 1 A g−1 when used as supercapacitors electrode in 0.5 M K2SO4.

Highlights

IntroductionSupercapacitors are considered to be one of the most promising energy storage devices due to their higher energy density compared to conventional capacitors, higher power density than batteries, long cycle life, and environmental friendliness.[1,2,3,4,5,6,7,8] As electrode materials for supercapacitors, vanadium pentoxide (V2O5) has attracted much attention because of its extensive properties such as layered structure, low cost, high theoretical capacity, as well as stable working voltage.[9,10,11,12,13,14] the collapse of the layered structure due to insertion/ extraction of ions greatly limits its application in supercapacitors.[14]
The marked diffraction peaks indicate that the X-ray diffraction (XRD) spectrum of V2 agrees well with orthorhombic V2O5 (JCPDS 41-1426; space group: pmmn (59))
These results suggest that the amount of disodium citrate plays an important role in controlling the crystal phase of the products

Summary

Introduction

Supercapacitors are considered to be one of the most promising energy storage devices due to their higher energy density compared to conventional capacitors, higher power density than batteries, long cycle life, and environmental friendliness.[1,2,3,4,5,6,7,8] As electrode materials for supercapacitors, vanadium pentoxide (V2O5) has attracted much attention because of its extensive properties such as layered structure, low cost, high theoretical capacity, as well as stable working voltage.[9,10,11,12,13,14] the collapse of the layered structure due to insertion/ extraction of ions greatly limits its application in supercapacitors.[14]. The preparation of uniform V2O5 nanoballs displaying a speci c capacitance of 479 F gÀ1 by a solvothermal treatment of ammonium metavanadate at 180 C for 48 h has been reported by Yang et al.[9] Orthorhombic single-crystalline V2O5 nanobelts with 30–80 nm in width and 30–40 nm in thickness were synthesized through a hydrothermal process at 180 C for 24 h but the electrochemical properties weren't explored.[10] there are some problems such as low solubility of raw material, easy agglomeration of nal products and long reaction time for hydrothermal and solvothermal methods. The way to overcome these limitations by additive agent has drawn great interest of researchers.[22,23,24] there are few reports on preparation of V2O5 nanomaterials using disodium citrate as additive agent. Providing V2O5 nanowires about 20 nm in diameter within short reaction time, this synthesis method used in this article shows great application prospects

Preparations of V2O5 nanowires

Characterization

Electrochemical measurements

Results and discussion

Conclusions