Synthesis and Characterization of Electrochemical Double Layer Capacitors Using Aligned Architectures of Carbon Nanotubes - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Synthesis and Characterization of Electrochemical Double Layer Capacitors Using Aligned Architectures of Carbon Nanotubes write by Rakesh Kumar Shah. This book was released on 2008. Synthesis and Characterization of Electrochemical Double Layer Capacitors Using Aligned Architectures of Carbon Nanotubes available in PDF, EPUB and Kindle. Electrochemical double layer capacitors, (EDLC's or supercapacitors) have received a lot of attention as viable electrical energy storage devices due to their ability for delivering high powers. Supercapacitor devices were fabricated using freestanding aligned multiwall carbon nanotubes (AMWNTs) as well as AMWNTs grown on metallic alloy (inconel 600) substrates. A novel technique of air assisted chemical vapor deposition (CVD) method was employed for the synthesis of the AMWNTs. The carbon nanotubes (CNTs) were characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The performances of the supercapacitor devices were tested using a variety of standard techniques such as cyclic voltammetry, galvanostatic constant current charge/discharge, and impedance spectroscopy. The maximum value of specific capacitance, measured at 5 mA constant discharge current, for various devices were in the range of 14.6-21.57 F/g for the supercapacitors fabricated from CNT grown on an inconel substrate. The maximum value of energy density and power density of the whole capacitor devices were 1.48 Wh/Kg and 2695.87 W/Kg, respectively. These results show that the electrodes fabricated from Inconel sheets with AMWNT grown directly on them have the potential to be superb electrode material for the fabrication of high performance EDLC's.
Three-Dimensional Nanoarchitectures
Three-Dimensional Nanoarchitectures - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Three-Dimensional Nanoarchitectures write by Weilie Zhou. This book was released on 2011-08-04. Three-Dimensional Nanoarchitectures available in PDF, EPUB and Kindle. Devices built from three-dimensional nanoarchitectures offer a number of advantages over those based on thin-film technology, such as larger surface area to enhance the sensitivity of sensors, to collect more sunlight to improve the efficiency of solar cells, and to supply higher density emitters for increased resolution in flat panel displays. Three-dimensional nanoscale assembly has already been used to generate many prototypes of devices and sensors, including piezoelectric nanogenerators based on ZnO nanowire arrays, photovoltaic devices based on silicon nanowire array p-n junctions, and highly sensitive gas sensors based on metal oxide nanowire arrays among others. Three-Dimensional Nanoarchitectures: Designing Next-Generation Devices describes state-of-the-art synthesis, integration, and design strategies used to create three-dimensional nanoarchitectures for functional nanodevice applications. With a focus on synthesis and fabrication methods for three-dimensional nanostructure assembly and construction, coverage includes resonators, nanophotonics, sensors, supercapacitors, solar cells, and more. This book is an essential reference for a broad audience of researchers in materials science, chemistry, physics, and electrical engineering who want the latest information on synthesis routes and assembly methods. Schematics of device integration and mechanisms as well as plots of measurement data are included.
Fabrication and Characterization of Nano Carbon-based Electrochemical Double-layer Capacitors
Fabrication and Characterization of Nano Carbon-based Electrochemical Double-layer Capacitors - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Fabrication and Characterization of Nano Carbon-based Electrochemical Double-layer Capacitors write by Jin Hee Kang. This book was released on 2015. Fabrication and Characterization of Nano Carbon-based Electrochemical Double-layer Capacitors available in PDF, EPUB and Kindle. Porous electrode is a key component in electrochemical double layer capacitors (EDLCs), also called supercapacitors, which provides effective charge storage sites and ion transport channels along the electric double-layer interface between a solid electrode surface and liquid electrolyte. In particular, the micro-structure of an electrode is extremely important to optimize the ion's transport channel and subsequently increasing the ion storage capacity on porous electrodes. This research focuses on three types of porous carbon materials, activated carbon (AC), graphene and single-walled carbon nanotube (SWCNT), with varying surface area and internal porosity as electrode materials. Depending on the type of carbon materials, three different fabrication methods, cast-coating, electrophotretic deposition (EPD) and vacuum filtration deposition, were developed to exploit the unique properties of electrodes. Their structural, electrochemical, thermodynamic properties were characterized, and the temperature/frequency-dependent capacitive and resistive behaviors were correlated to the microstructures, BET surface area, pore size and pore size distribution (PSD) of the electrodes. Under various operating temperatures between -30 °C and 60 °C and frequency operations, these electrochemical parameters were quantified using cyclic voltammetry (CV), constant current charging/discharging (CCD) measurements and electrochemical impedance spectroscopy (EIS). The differences in their temperature/frequency-dependent characteristics, including their current response to high scan rates, capacitance retention, resistance variation, and degradation of energy and power densities, were addressed by investigating ion kinetics and transport into the micro-, or meso-pores of the electrodes. An equivalent circuit model for an EDLC device was proposed through analyzing the EIS measurements. This model was developed based on the Grahame theory, while the effects of charge diffusion and the ion adsorption at the double-layer interface and bulk media were investigated. This circuit model, upon its validation against the EIS data, was successfully applied to characterize practical EDLC devices. Experimental results were obtained from different EDLC cells consisting of activated carbon-based electrodes and two distinct electrolytes, aqueous (H2SO4) and organic (Et4NBF4/PC). The model predicted the useful parameters (such as charge transfer, diffusion, adsorption and bulk media impedance) which help interpret electrochemical processes at the electrode/electrolyte interface. The quantitative dependence of impedance on the applied electrode potential was analyzed for the two electrolytes during charging/discharging, and its correlation with the internal resistance (referred ESR) was derived. Their temperature-dependent electrochemical properties were also investigated using a specified characterization procedure, and the capacitance, internal resistance and energy/power densities of the two capacitors were quantified. The temperature dependency of their impedances was analyzed through simulations of the EIS data by the proposed equivalent circuit model. The simulated impedances were then utilized to address the performance discrepancies between the two electrolytes.
Carbon Nanotubes
Carbon Nanotubes - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Carbon Nanotubes write by Stephan Parker Turano. This book was released on 2005. Carbon Nanotubes available in PDF, EPUB and Kindle. Carbon nanotubes (CNTs) have become a popular area of materials science research due to their outstanding material properties coupled with their small size. CNTs are expected to be included in a wide variety of applications and devices in the near future. Among these devices which are nearing mass production are electrochemical double layer (ECDL) supercapacitors. The current methods to produce CNTs are numerous, with each synthesis variable resulting in changes in the physical properties of the CNT. A wide array of studies have focused on the effects of specific synthesis conditions. This research expands on earlier work done using bulk nickel catalyst, alumina supported iron catalyst, and standard chemical vapor deposition (CVD) synthesis methods. This work also investigates the effect of an applied voltage to the CVD chamber during synthesis on the physical nature of the CNTs produced. In addition, the work analyzes a novel nickel catalyst system, and the CNTs produced using this catalyst. The results of the effects of synthesis conditions on resultant CNTs are included. Additionally, CNT based ECDL supercapacitors were manufactured and tested. Scanning electron microscope (SEM) analysis reveals that catalyst choice, catalyst thickness, synthesis temperature, and applied voltage have different results on CNT dimensions. Nanotube diameter distribution and average diameter data demonstrate the effect of each synthesis condition. Additionally, the concept of an alignment parameter is introduced in order to quantify the effect of an electric field on CNT alignment. CNT based ECDL supercapacitors testing reveals that CNTs work well as an active material when a higher purity is achieved. The molarity of the electrolyte also has an effect on the performance of CNT based ECDL supercapacitors. On the basis of this research, we conclude that CNT physical dimensions can be moderately controlled based on the choice of synthesis conditions. Also, the novel nickel catalyst system investigated in this research has potential to produce bulk quantities of CNT under specific conditions. Finally, purified CNTs are recommended as a suitable active material for ECDL supercapacitors.
Nanomaterials for Supercapacitors
Nanomaterials for Supercapacitors - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Nanomaterials for Supercapacitors write by Ling Bing Kong. This book was released on 2017-11-22. Nanomaterials for Supercapacitors available in PDF, EPUB and Kindle. New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. Supercapacitors have been widely acknowledged to be promising devices for energy storage. This book describes the latest progress in the discovery and development of nanoelectrolytes and nanoelectrodes for supercapacitor applications.
