Growth of Carbon Nanotubes on Electrospun Cellulose Fibers for High Performance Supercapacitors

Abstract

We report the production of cellulose-derived hybrid carbon nanofiber (CNF)/ carbon nanotubes (CNTs) electrodes for the fabrication of high-performance supercapacitors. The CNTs were grown via a floating catalyst chemical vapor deposition (CVD) method on the top surface of electrospun cellulose-derived CNFs. The morphology of these hybrid CNF/CNTs fibrous structures was investigated using scanning electron and transmission electron microscopy. The development of these carbon structures was characterized using Raman spectroscopy. The electrochemical performance of the devices including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), electrochemical impedance spectroscopy measurements (EIS), and electrochemically stability was carried out. These hybrid CNF/CNTs electrodes had a high value of specific capacitance of 149 F g −1 at a current density 0.5 A g −1 , an increase of 15% compared with pristine CNFs. The BET specific surface area increases from 712 m 2 g −1 to 1211 m 2 g −1 from pristine CNFs to hybrid CNF/CNTs, leading to a specific capacitance (per unit area) of ∼170 mF cm −2 . These supercapacitors also retain 90% of the original capacitance over 1000 cycles, showing an excellent stability. This method of supercapacitor electrode production is suggested as a basis to convert a sustainable cellulosic material into a useful energy storage material.

Structural supercapacitors using a solid resin electrolyte with carbonized electrospun cellulose/carbon nanotube electrodes

“…No other carbon impurities were observed after CVD, in agreement with a previous study [18]. The absorptiondesorption isotherms for these materials and their respective surface areas have been previously reported; surface area was found to grow from 712 to 1211 m 2 g -1 after growth of CNTs on CNF [8].…”

“…From previous work by Kong et al [23], graphitization cannot be achieved at temperatures below * 1600°C, therefore the crystallite size is not expected to be as large as for a fully graphitized structure (L a [ 2 nm) for the CF900 and CF1500 samples. The relationship between I D /I G and L a , therefore, obtained for L a \ 2 nm is [8,24,25]…”

“…Electrodes were prepared by carbonization of electrospun de-acetylated cellulose acetate fibres at a temperature of 900°C, followed by CVD to generate CNTs, and finally a KOH activation of their surface. A full description of the production of these fibres from cellulose acetate precursor is contained within a previous publication [8]. Plain carbon fibres and CNTs decorated filaments are subsequently denoted as CF900 and CF900/CNTs, respectively.…”

“…These electrodes can be used for supercapacitors, due to their high surface area to volume ratios, desirable porosity, and excellent mechanical properties [7]. We have recently shown that carbon nanotubes (CNTs) can be grown on the surface of carbon fibres, produced by an electrospinning method, improving the electrocapacitive performance [8]. Growing CNTs on the surface of the carbon fibres could also be an effective approach to enhance the interfacial strength of a structural supercapacitor, as has been shown to be the case with traditional composite materials [9,10].…”

Grown Carbon Nanotubes on Electrospun Carbon Nanofibers as a 3D Carbon Nanomaterial for High Energy Storage Performance

“…The specific surface area of the activated CNTs/CNFs reached 1840 m 2 g −1 with a pore volume of 1.21 m 3 g −1 , while the surface area of deactivated hybrid CNTs/CNFs just 371 m 2 g −1 that due to the open side of CNTs, as reported Chen et al . Li et al . reported about the huge surface area of hybrid CNTs grown/CNFs 1211 m 2 g −1 of the sample treated at 900 °C with high pores volume 0.3 m 3 g −1 .…”