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Sweet nanotech batteries
April 11, 2008Nanotechnology could solve lithium battery charging problems
Nanotechnology could improve the life of the lithium batteries used in portable devices, including laptop computers, mp3 players, and mobile phones. Research to be published in the Inderscience publication - International Journal of Nanomanufacturing - demonstrates that carbon nanotubes can prevent such batteries from losing their charge capacity over time.
Researchers at the Shenyang National Laboratory for Materials Science, in China, have been investigating how to improve the kind of rechargeable batteries that are almost ubiquitous in today's portable devices. Mobile phones, mp3 players, personal digital assistants (PDAs), and laptop computers usually use lithium-ion batteries to give them portability. However, Li-ion batteries suffer from degradation especially when they get too hot or too cold and eventually lose the capacity to be fully recharged. This means a loss of talk time for mobile phone users and often no chance to use a laptop for the whole of a long haul flight.
The problem of the slow degradation of Li-ion batteries is usually due to the formation of a solid electrolyte interphase film that increase the batteries internal resistance and prevents a full recharge. Researchers have suggested using silicon in the composition of the negative electrode material in Li-ion batteries to improve charge capacity. However, this material leads to even faster capacity loss as it repeatedly alloys and then de-alloys during charge-discharge cycles.
Shengyang's Hui-Ming Cheng and colleagues have turned to carbon nanotubes (CNTs) to help them use silicon (Si) as the battery anode but avoid the problem of large volume change during alloying and de-alloying. Carbon nanotubes resemble rolled-up sheets of hexagonal chicken wire with a carbon atom at the crossover points of the wires and the wires themselves being the bonds between carbon atoms, and they can be up to a millimeter long but mere nanometers in diameter.
The researchers grew carbon nanotubes on the surface of tiny particles of silicon using a technique known as chemical vapor deposition in which a carbon-containing vapor decomposes and then condenses on the surface of the silicon particles forming the nanoscopic tubes. They then coated these particles with carbon released from sugar at a high temperature in a vacuum. A separate batch of silicon particles produced using sugar but without the CNTs was also prepared.
With the new Si-CNT anode material to hand, the team then investigated how well it functioned in a prototype Li-ion battery and compared the results with the material formed from sugar-coated silicon particles.
They found that after twenty cycles of the semi-cell experiments, the sugar-coated Si-CNT composite material achieved a discharge capacity of 727 milliamp hours per gram. In contrast the charge capacity of the simple sugar-coated particles had dropped to just 363 mAh per gram.
Inderscience Publishers
The problem of the slow degradation of Li-ion batteries is usually due to the formation of a solid electrolyte interphase film that increase the batteries internal resistance and prevents a full recharge. Researchers have suggested using silicon in the composition of the negative electrode material in Li-ion batteries to improve charge capacity. However, this material leads to even faster capacity loss as it repeatedly alloys and then de-alloys during charge-discharge cycles.
Shengyang's Hui-Ming Cheng and colleagues have turned to carbon nanotubes (CNTs) to help them use silicon (Si) as the battery anode but avoid the problem of large volume change during alloying and de-alloying. Carbon nanotubes resemble rolled-up sheets of hexagonal chicken wire with a carbon atom at the crossover points of the wires and the wires themselves being the bonds between carbon atoms, and they can be up to a millimeter long but mere nanometers in diameter.
The researchers grew carbon nanotubes on the surface of tiny particles of silicon using a technique known as chemical vapor deposition in which a carbon-containing vapor decomposes and then condenses on the surface of the silicon particles forming the nanoscopic tubes. They then coated these particles with carbon released from sugar at a high temperature in a vacuum. A separate batch of silicon particles produced using sugar but without the CNTs was also prepared.
With the new Si-CNT anode material to hand, the team then investigated how well it functioned in a prototype Li-ion battery and compared the results with the material formed from sugar-coated silicon particles.
They found that after twenty cycles of the semi-cell experiments, the sugar-coated Si-CNT composite material achieved a discharge capacity of 727 milliamp hours per gram. In contrast the charge capacity of the simple sugar-coated particles had dropped to just 363 mAh per gram.
Inderscience Publishers
Carbon Nanotubes Current Events and Carbon Nanotubes News RSSCaltech scientists develop DNA origami nanoscale breadboards for carbon nanotube circuits
In work that someday may lead to the development of novel types of nanoscale electronic devices, an interdisciplinary team of researchers at the California Institute of Technology (Caltech) has combined DNA's talent for self-assembly with the remarkable electronic properties of carbon nanotubes, thereby suggesting a solution to the long-standing problem of organizing carbon nanotubes into nanoscale electronic circuits.
Breakthrough in industrial-scale nanotube processing
Rice University scientists today unveiled a method for the industrial-scale processing of pure carbon-nanotube fibers that could lead to revolutionary advances in materials science, power distribution and nanoelectronics.
Next-generation microcapsules deliver 'chemicals on demand'
Scientists in California are reporting development of a new generation of the microcapsules used in carbon-free copy paper, in which capsules burst and release ink with pressure from a pen.
Study shows how carbon nanotubes can affect lining of the lungs
Carbon nanotubes are being considered for use in everything from sports equipment to medical applications, but a great deal remains unknown about whether these materials cause respiratory or other health problems.
Advance in 'nano-agriculture': Tiny stuff has huge effect on plant growth
With potential adverse health and environmental effects often in the news about nanotechnology, scientists in Arkansas are reporting that carbon nanotubes (CNTs) could have beneficial effects in agriculture.
A recipe for controlling carbon nanotubes
Nanoscopic tubes made of a lattice of carbon just a single atom deep hold promise for delivering medicines directly to a tumor, sensors so keen they detect the arrival or departure of a single electron, a replacement for costly platinum in fuel cells or as energy‐saving transistors and wires.
Friction force differences could offer a new means for sorting and assembling nanotubes
Nanotubes and nanowires are promising building blocks for future integrated nanoelectronic and photonic circuits, nanosensors, interconnects and electro-mechanical nanodevices. But some fundamental issues remain to be resolved - among them, how to position and manipulate the tiny tubes.
New biosensor can detect bacteria instantaneously
A research group from the Rovira i Virgili University (URV) in Tarragona has developed a biosensor that can immediately detect very low levels of Salmonella typhi, the bacteria that causes typhoid fever.
Researchers design new graphene-based, nano-material with magnetic properties
An international team of researchers has designed a new graphite-based, magnetic nano-material that acts as a semiconductor and could help material scientists create the next generation of electronic devices like microchips.
Researchers Pinpoint Neural Nanoblockers in Carbon Nanotubes
A team of Brown University scientists has pinpointed why carbon nanotubes tend to block a critical signaling pathway in neurons.
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Carbon Nanotubes: Basic Concepts and Physical Properties by Stephanie Reich (Author), Christian Thomsen (Author), Janina Maultzsch (Author) Carbon nanotubes are exceptionally interesting from a fundamental research point of view. Many concepts of one-dimensional physics have been verified experimentally such as electron and phonon confinement or the one-dimensional singularities in the density of states; other 1D signatures are still under debate, such as Luttinger-liquid behavior. Carbon nanotubes are chemically stable, mechanically very strong, and conduct electricity. For this reason, they open up new perspectives for various applications, such as nano-transistors in circuits, field-emission displays, artificial muscles, or added reinforcements in alloys. This text is an introduction to the physical concepts needed for investigating carbon nanotubes and other one-dimensional solid-state systems. Written for... |
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Carbon Nanotubes: Synthesis, Structure, Properties and Applications by et al R.E. Smalley (Foreword) (Author) This book gives a comprehensive review of the present status of research in this fast moving field by researchers actively contributing to the advances. After a short introduction and a brief review of the relation between carbon nanotubes, graphite and other forms of carbon, the synthesis techniques and growth mechanisms for carbon nanotubes are described. This is followed by reviews on nanotube electronic structure, electrical, optical, and mechanical properties, nanotube imaging and spectroscopy, and nanotube applications. |
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Carbon Nanotubes: Properties and Applications by Michael J. O'Connell (Editor) Since their discovery more than a decade ago, carbon nanotubes (CNTs) have held scientists and engineers in captive fascination, seated on the verge of enormous breakthroughs in areas such as medicine, electronics, and materials science, to name but a few. Taking a broad look at CNTs and the tools used to study them, Carbon Nanotubes: Properties and Applications comprises the efforts of leading nanotube researchers led by Michael O’Connell, protégé of the late father of nanotechnology, Richard Smalley. Each chapter is a self-contained treatise on various aspects of CNT synthesis, characterization, modification, and applications. The book opens with a general introduction to the basic characteristics and the history of CNTs, followed by discussions on synthesis methods and the... |
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Understanding Carbon Nanotubes: From Basics to Applications (Lecture Notes in Physics) by A. Loiseau (Editor), P. Launois (Editor), P. Petit (Editor), S. Roche (Editor), J.-P. Salvetat (Editor) This volume presents the foundations of carbon nanotube science including the most recent developments and the prospects for technological applications. Each chapter begins with a tutorial introduction to the relevant interdisciplinary topics from physics, chemistry or materials science. These summaries of the essential background knowledge are followed by detailed presentations of specific issues. The latter include: polymorphism of carbon and the microstructure of its phases; synthesis methods and growth mechanisms; structural analysis by electron microscopy; spectroscopic methods; electronic structure; transport; mechanical and surface properties of nanotubes and composites. All readers, be they students or experienced researchers, will come to appreciate how progress in nanotube... |
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