Future scope and directions of nanotechnology in creating next-generation supercapacitors

The primary global research scheme of the 21st century is nanotechnology. Looking forward to the future, nanotechnologies’ generalized diffusion will seem to turn them into supplies, generating more space for privileged and superior values of applications such as information technology, nanoenergy, nanobiotechnologies, and nanomaterials.1-5 In general, nanotechnology is the understanding and controlling of the matters of dimensions of approximately 1-100 nm, in which a unique phenomenon facilitates novel applications.2 The application domains covered by nanotechnology are discussed in detail in this chapter

Nanoporous layered graphene hydrogel for controlled drug delivery

Graphene-related materials with tuneable pore sizes in the nanoscale range offer the potential to address significant challenges in biomolecule separation, controlled delivery of drugs, selective biosensor, rechargeable batteries, supercapacitors and solar cells. Layered assemblies of graphene-related sheets with physical and chemical cross-linkers between the sheets have been recognized as one possible strategy for making such nanoporous materials. However, current approaches give very limited control over the pore size distribution, particularly with regards control of the mean pore size and the degree of spread around it. This work particularly outlined the design, synthesis and characterization of a nanoporous layered graphene hydrogel produced via peptide-mediated self-assembly of reduced graphene oxide (rGO). The peptides have been designed using molecular dynamics (MD) simulation to self-assemble the rGO sheets with a desired inter-sheet spacing (pore size). The hydrogel material was synthesized and characterized using a range of methods to demonstrate the desired pore size is achieved. In the second body of this work, the rGO binding peptide hydrogel, denoted rGOPH, showed to be a promising candidate for the controlled delivery of an anti-cancer drug. In particular, it was shown that the rGOPH has a high doxorubicin (DOX) loading capacity achieved through physical adsorption within its nanoporous structure. Design of experiments (DoE) and statistical analysis on different preparation parameters revealed that pore size and drug loading capacity are tuneable. In the final part of the work, a desirable pH-dependant drug release properties was shown by rGOPH nominating such hydrogels as promising candidates for cancer therapy. In addition, the hydrogel materials exhibited a high biocompatibility to the healthy cells for their attachments and proliferation. The cytotoxicity of the hydrogel materials demonstrated to be low. The work reported in this thesis has provided new computational and experimental understanding for fabrication of graphene based nano-constructs with tuneable pore size as well as new methodologies and approaches. Although the focus was only on one designed peptide, the design and methodologies developed here are quite potent and, therefore, lay the foundations for fabrication of nanoporous graphene based materials of virtually any pore size to suit the needs of users in broader applications (such as nanomedicines, nanobiotechnology, nanoelectronics, biosensors and biomolecular and nanoparticle separations).Thesis (Ph.D.) -- University of Adelaide, School of Chemical Engineering, 2015

Remarkable stability of supercapacitor material synthesized by manganese oxide filled in multiwalled carbon nanotubes

Improving the electrochemical stability of manganese oxide/multiwalled carbon nanotubes (MnO 2 /MWCNTs) nanocomposites is of great importance to many electrochemical supercapacitor applications. In this study, the electrochemical properties of MnO 2 filled inside the cavity of MWCNTs were investigated for the first time. The prepared nanocomposite was characterized by means of X-ray photoelectron spectroscopy (XPS), X-ray diffraction patterns (XRD), transmission electron microscopy (TEM) images, scanning electron microscopy (SEM) together with energy dispersive X-ray spectroscopy (EDX) and thermogravimetric analyses (TGA). Electrochemical characterization has been performed using cyclic voltammetry (CV), galvanostatic charging/discharging (CD) test. The TEM image, XRD analysis confirmed the high structural stability and CD test complied the high electrochemical stability of the prepared nanocompo-site. Besides, MnO 2 /MWCNTs nanocomposite supercapacitor showed superior cycling stability in the potential range of 0-1.0V due to the filling of the electroactive material inside the tubes and retained 96% of initial capacitance even over 200 cycles. © 2010 Bentham Science Publishers Ltd

Multiwalled carbon nanotubes based nanocomposites for supercapacitors: A review of electrode materials

Electrode materials are the most important factors to verify the properties of the electrochemical supercapacitor. In this paper, the storage principles and characteristics of electrode materials, including carbon-based materials, transition metal oxides and conducting polymers for supercapacitors are depicted in detail. Other factors such as electrode separator and electrolyte are briefly investigated. Recently, several works are conducted on application of multiwalled carbon nanotubes (MWCNTs) and MWCNTs-based electrode materials for supercapacitors. MWCNTs serve in experimental supercapacitor electrode materials result in specific capacitance (SC) value as high as 135 Fg -1 . Addition of pseudocapacitive materials such as transition metal oxides and conducting polymers in the MWCNTs results in electrochemical performance improvement (higher capacitance and conductivity). The nanocomposites of MWCNTs and pseudocapacitive materials are the most promising electrode materials for supercapacitors because of their good electrical conductivity, low cost and high mass density. © 2012 World Scientific Publishing Company

Highly efficient hybrid supercapacitor material from nickel-manganese oxides/MWCNT/PEDOT nanocomposite

A novel ternary nanocomposite of nickel-manganese oxides/multi-walled carbon nanotubes (NMO/MWCNTs) coated with poly (3,4-ethylenedioxythiophene) (PEDOT) was prepared by chemical oxidation method. The filling of NMO particles inside MWCNTs and the uniform coating of NMO/MWCNTs with PEDOT intensified the capacitive behavior of MWCNTs. The lowest IR drop (0.1 V) and highest specific capacitance (SC) values of 526.55 F/g of NMO/MWCNTs/PEDOT imply it as highly efficient hybrid supercapacitor materials in 6 M KOH electrolyte. © 2010 World Scientific Publishing Company