1,723,218 research outputs found
Silver Nanowires for Supercapacitor Electrodes
No full textWe present a new hybrid material composed of molybdenum (IV) oxide (MoO2) shell on highly conducting silver nanowire (Ag NW) core in the network form for the realization of coaxial Ag NW/MoO2 nanocomposite supercapacitor electrodes. Ag NWs were simply spray coated onto glass substrates to form conductive networks and conformal MoO2 layer was electrodeposited onto the Ag NW network to create binder-free coaxial supercapacitor electrodes. Combination of Ag NWs and pseudocapacitive MoO2 generated an enhanced electrochemical energy storage capacity and a specific capacitance of 500.7 F/g was obtained at a current density of 0.25 A/g. Fabricated supercapacitor electrodes showed excellent capacity retention after 5000 cycles. The methods and the design investigated herein open a wide range of opportunities for nanowire based coaxial supercapacitors
Ion Dynamics of Water‐in‐Salt Electrolyte with Organic Solvents in Nanoporous Supercapacitor Electrodes
No full textWater-in-salt electrolytes blended with organics solvents, that is, organic solvent/water mixed electrolytes, are promising for applications in next-generation energy storage devices vitally needed for industrial electrification and decarbonization. However, the electrolyte ion diffusion behaviors within nanoporous supercapacitor electrodes are poorly understood. Here a systematic investigation into supercapacitor resistances and ion kinetics is carried out experimentally and with numerical simulations. The electrochemical results on the nanoporous electrodes reveal a nonmonotonic (decreasing, increasing, and then decreasing) trend of supercapacitor resistances with increasing solvent mobility, challenging the long-held views that supercapacitor resistances decrease with elevated mobility of organic solvent. The abnormal trend is examined by numerical molecular dynamics simulations of electrolyte ion diffusion within 0.95 nm nanochannels. The electrolyte conductivity is related to cation–anion interactions within nanochannels. We further confirm the crucial interplay of the van der Waals sizes of solvent molecules and channel width in determining electrolyte conductivity in nanoporous electrodes.No Full Tex
Flexible supercapacitor electrodes with silver nanowire networks
No full textSilver nanowires (Ag NWs) are appealing candidates for supercapacitor electrodes due to their high conductivity in addition to their allowance for all active materials to be in close contact to facilitate charge transport. All are very important to attain maximum charge accumulation provided that Ag NWs are electrochemically stable within the utilized potential window. In this work, high aspect ratio Ag NWs are used within a coaxial and/or network-like flexible nanocomposite structure in supercapacitor electrodes. Utilization of Ag NWs as conductive templates also results in rapid deposition of electrode active materials. We have fabricated supercapacitors using Ag NWs and their nanocomposites with molybdenum oxide (MoO2) (500.7 F g-1) [1], nickel hydroxide (Ni(OH)2) (1165.2 F g-1) [2], polypyrrole (PPy) (509 F g-1) and some PEDOT derivatives (61.5 F g-1). Highly conductive Ag NWs were utilized as the only current collectors and templates for these electrode active materials. Electrochemical properties of the fabricated Ag NW based flexible nanocomposite supercapacitor electrodes were investigated through galvanostatic charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy. We will present a detailed analysis of utilization of Ag NWs in the fabricated supercapacitors to underline their charge transport behavior. Our results showed the potential of the use of Ag NWs in energy storage devices and the structures presented in this work is highly plausible and can be easily extended to other metal nanowire, metal oxide and conducting polymer systems
Graphene Nanocomposite Materials for Supercapacitor Electrodes
No full textGraphene and related materials (graphene oxide, reduced graphene oxide) as a subclass of carbon materials and their composites have been examined in various functions as materials in supercapacitor electrodes. They have been suggested as active masses for electrodes in electrochemical double-layer capacitors, tested as conducting additives for redox-active materials showing only poor electronic conductivity, and their use as a coating of active materials for corrosion and dissolution protection has been suggested. They have also been examined as a corrosion-protection coating of metallic current collectors; paper-like materials prepared from them have been proposed as mechanical support and as a current collector of supercapacitor electrodes. This entry provides an overview with representative examples. It outlines advantages, challenges, and future directions
Revitalizing carbon supercapacitor electrodes with hierarchical porous structures
No full textThe review offers a comprehensive overview on the synthesis strategies and fundamental understandings of hierarchical porous carbons as supercapacitor electrodes.</p
Polyaniline-coated carbon papers for supercapacitor electrodes
Full text linkGraphene and carbon nanotubes are promising materials for supercapacitor electrodes because of their high specific surface area and excellent electrical, thermal, and mechanical properties. However, these materials suffer from a high manufacturing cost and some aggregation of graphene layers or the presence of toxic residual metallic impurities of carbon nanotubes
Gold nanoparticle embedded paper with mechanically exfoliated graphite as flexible supercapacitor electrodes
No full textWe report a new method for the fabrication of flexible supercapacitor electrodes wherein mechanically exfoliated graphite on paper containing gold nanoparticles is used as supercapacitor electrodes. It has been found that the supercapacitor electrode made of paper containing gold nanoparticle with graphite exfoliation yields a capacitance, which is about 4.3 times higher than that of the electrodes without gold nanoparticles
Template Free-Synthesis of Polypyrrole Microtubes for Supercapacitor Electrodes
No full textThe purpose of this work is to develop a simple, scalable and template-free method to synthesize conducting polymer nano/micro-structures for supercapacitor electrodes. The microstructure and electrochemical properties of structure polypyrrole on various mesh substrates is investigated
Flexible supercapacitor electrodes based on real metal-like cellulose papers
No full textAbstractThe effective implantation of conductive and charge storage materials into flexible frames has been strongly demanded for the development of flexible supercapacitors. Here, we introduce metallic cellulose paper-based supercapacitor electrodes with excellent energy storage performance by minimizing the contact resistance between neighboring metal and/or metal oxide nanoparticles using an assembly approach, called ligand-mediated layer-by-layer assembly. This approach can convert the insulating paper to the highly porous metallic paper with large surface areas that can function as current collectors and nanoparticle reservoirs for supercapacitor electrodes. Moreover, we demonstrate that the alternating structure design of the metal and pseudocapacitive nanoparticles on the metallic papers can remarkably increase the areal capacitance and rate capability with a notable decrease in the internal resistance. The maximum power and energy density of the metallic paper-based supercapacitors are estimated to be 15.1 mW cm−2 and 267.3 μWh cm−2, respectively, substantially outperforming the performance of conventional paper or textile-type supercapacitors.</jats:p
Hierarchical metal-oxide nanostructures for high-performance supercapacitor electrodes
No full textRational construction of metal oxides materials with different functions into a proper integrated system represents a promising way to create next generation electrodes materials. In this thesis, we employed technologies for the rational design and facile construction of several metal oxide based hierarchical nanostructures for their application in electrochemical energy storage devices.
Firstly, systematic studies are conducted to CoO and Ni(OH)2–based nanoheterostructures to understand the role of the hierarchical structure design and synergistic effect in their good electrochemical properties. Second, we explore the application of atomic layer deposition (ALD) in the fabrication of novel nanostructures for enhanced electrochemical performance as supercapacitor electrodes.
In all, the thesis project provides several demonstrations of novel and high-performance metal oxide based supercapacitor electrodes. The controlled fabrication and functional integration of dissimilar materials on the nanoscale represents an important step towards application of these materials for supercapacitor application in the future.DOCTOR OF PHILOSOPHY (SPMS
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