Reduced holey graphene oxide film and carbon nanotubes sandwich structure as a binder-free electrode material for supercapcitor

Abstract

A novel carbon nanotubes (CNTs) and reduced holey graphene oxide film (RHGOF) sandwich structure has been fabricated to enhance its electrochemical properties. CNTs are grown by a catalyst assisted chemical vapor deposition technique, interpenetrated between the RHGOF layers. A RHGOF/CNTs hybrid film is used as a binder-free supercapacitor electrode. The grown CNTs in the graphene layers structure act as spacers and bridges to increase the counductivity of RHGOF, while the grown CNTs on the surfaces of the graphene contribute to increase the specific surface area of RHGOF. The results demonstrate that the synthesized porous, flexible and binder free hybrid electrode has advantages of higher ion diffusion rate, longer diffusion length and larger ion accessible surface area as compared to the pristine graphene which results in an extra ordinary galvanostatic charge-discharge specific capacitance of 557 F/g at a current density of 0.5 A/g, with excellent rate capabilities and superior cyclic stabilities.In recent era, environment adaptability, portability and compatibility of electronics, hybrid electric vehicles are becoming challenging issues. Energy storage devices having high performance are the part and parcel of these aforementioned devices 1 . Because of its promising adventages, supercapacitor is one of the fascinating energy storage device, such as fast dynamic response, high power density, longer life span and good capability rate 2,3 . Therefore, explicit studies of the characteristics of supercapcitor electrode materials are very essential components that ultimately affect its electrochemical properties 1,4-7 . Most recently, researchers are trying their best to prepare flexible type of electrode materials possessing good cyclic stability, high performance output in terms of charge-discharge rates and specific capacitance.Graphene (GR), being a 2D nano-structured material, has already been acknowledged as an attractive material for supercapacitor electrode. As a single thick sheet of carbon atoms, due to the numerous profound physic-chemical properties,it has been presaged for transfiguring a wide range of technological area [8][9][10][11] . Moreover, it has high unique mechanical flexibility intrinsic electrical conductivity, theoretical gravimetric capacitance of about 550 F/g and remarkably large theoretical surface area of 2630 m 2 /g [11][12][13] . On the contrary, due to the extended π-conjugation in the basal plane, pristine GR has van der Waals forces and π-π interaction. Thus, GR sheets are stacked with each other under these effects. Their irreversible agglomeration not only hinders the ion diffusion rate, but also decreases accessible surface area and consequent reduction in the gravimetric capacitance 14-17 . To improve its capacitive performance, numerous methodologies have already been proposed. For instance, to prevent the restacking, conducting carbon materials as an active channel (such as carbon black, carbon nanotubes (CNTs)) and conducting polymers (such as polyaniline), have been use...

Flexible doctor blade-coated abiotic cathodes for implantable glucose/oxygen biofuel cells

“…This result is highly expected since graphene has sparked a lot of interest in supercapacitor research due to its two-dimensional structure, which gives it unique qualities like greater electrical conductivity and mechanical properties, as well as a larger surface area compared to carbon nanotubes (CNTs). 47,48 To summarize, the results obtained by the CVs and the chronoamperometry tests demonstrate the D. Gr ability to electro-catalyze the ORR at a physiological pH, which is, from our point of view, an important result demonstrating the potential of the iron-nitrogen doped graphene (D. Gr) as a catalyst in the development of implantable abiotic cathodes. For in vivo applications, the electrochemical performances are generally presented per volume either per surface since for implantable devices, and from a medical point of view, the volume expression is more suitable.…”

“…This result is highly expected since graphene has sparked a lot of interest in supercapacitor research due to its two-dimensional structure, which gives it unique qualities like greater electrical conductivity and mechanical properties, as well as a larger surface area compared to carbon nanotubes (CNTs). 47,48…”

Metal–Organic Framework Materials for Electrochemical Supercapacitors

“…As the core of a supercapacitor, electrode materials play a key role in its performance [30,[33][34][35][36]. To realize the highly efficient energy storage and conversion of supercapacitors, developing novel electrode materials is essential.…”

Synthesis of holey graphene for advanced nanotechnological applications

“…Similar to HG, HGO/HrGO have also shown potential applications in the areas of energy storage, gas sensing, etc. [37][38][39][40][41] HG, along with HGO/HrGO, has shown various interesting properties and various methods have been developed and implemented to synthesize or modify the materials for numerous applications. Due to the similar properties and applications of HG and HGO or HrGO by the term, HG we in general refer to HGO or HrGO along with holy/porous graphene.…”

“…Similar to HG, HGO/HrGO have also shown potential applications in the areas of energy storage, gas sensing, etc. 37–41 …”