Posted by louise on Mar 15, 2010
A tiny scaffold-like titanium structure of Nanonets coated with silicon particles could pave the way for faster, lighter and longer-lasting Lithium-ion batteries(thinkpad x40 battery,thinkpad x41 battery), according to a team of Boston College chemists who developed the new anode material using nanotechnology.
The web-like Nanonets developed in the lab of Boston College Assistant Professor of Chemistry Dunwei Wang offer a unique structural strength, more surface area and greater conductivity, which produced a charge/re-charge rate five to 10 times greater than typical Lithium-ion anode material, a common component in batteries,thinkpad x40 battery,thinkpad x41 battery, for a range of consumer electronics, according to findings published in the current online edition of the American Chemical Society journal Nano Letters.
In addition, the Nanonets proved exceptionally durable, showing a negligible drop-off in capacity during charge and re-charge cycles. The researchers observed an average of 0.1% capacity fade per cycle between the 20th and the 100th cycles.
“As researchers pursue the next generation of re-chargeable Lithium-ion battery technology,thinkpad x40 battery, a premium has been placed on increased power and a greater battery life span,” said Wang. “In that context, the Nanonet device makes a giant leap toward those two goals and gives us a superior anode material.”
Lithium-ion batteries are commonly used in consumer electronics devices. This type of rechargeable battery allows Lithium ions to move from the anode electrode to the cathode when in use,lenovo thinkpad adapter. When charged, the ions move from cathode back to the anode.
The structure and conductivity of the Nanonets improved the ability to insert and extract Lithium ions from the particulate Silicon coating, the team reported. Running at a charge/discharge rate of 8,400 milliamps per gram (mA/g) — which is approximately five to 10 times greater than similar devices — the specific capacity of the material was greater than 1,000 milliamps-hour per gram (mA-h/g). Typically, laptop Lithium-ion batteries are rated anywhere between 4,000 and 12,000 mA/h, meaning it would only take between four and 12 grams of the Nanonet anode material to achieve similar capacity.
Wang said the capability to preserve the crystalline Titanium Silicon core during the charge/discharge process was the key to achieving the high performance of the Nanonet anode material. Additional research in his lab will examine the performance of the Nanonet as a cathode material.
Posted by louise on Feb 22, 2010
Simply coating a sheet of paper with ink made of carbon nanotubes and silver nanowires makes a highly conductive storage device, said Yi Cui, assistant professor of materials science and engineering.
“Society really needs a low-cost, high-performance energy storage device, such as batteries (thinkpad x40 battery,thinkpad x41 battery)and simple supercapacitors,” he said.
Like batteries, capacitors hold an electric charge, but for a shorter period of time. However, capacitors can store and discharge electricity much more rapidly than a battery.
Cui’s work is reported in the paper “Highly Conductive Paper for Energy Storage Devices,” published online in the Proceedings of the National Academy of Sciences.
“These nanomaterials are special,” Cui said. “They’re a one-dimensional structure with very small diameters.” The small diameter helps the nanomaterial ink stick strongly to the fibrous paper, making the thinkpad x40 battery and supercapacitor very durable. The paper supercapacitor may last through 40,000 charge-discharge cycles — at least an order of magnitude more than lithium batteries. The nanomaterials also make ideal conductors because they move electricity along much more efficiently than ordinary conductors, Cui said.
Bing Hu, a post-doctoral fellow, prepares a small square of ordinary paper to with an ink that will deposit nanotubes on the surface that can then be charged with energy to create a battery,40Y6799,92p1089,92p1137.
Cui had previously created nanomaterial energy storage devices using plastics. His new research shows that a paper battery is more durable because the ink adheres more strongly to paper (answering the question, “Paper or plastic?”). What’s more, you can crumple or fold the paper battery, or even soak it in acidic or basic solutions, and the performance does not degrade. “We just haven’t tested what happens when you burn it,” he said.
The flexibility of paper allows for many clever applications. “If I want to paint my wall with a conducting energy storage device,” Cui said, “I can use a brush.” In his lab, he demonstrated the thinkpad x41 battery to a visitor by connecting it to an LED (light-emitting diode), which glowed brightly.
A paper supercapacitor may be especially useful for applications like electric or hybrid cars, which depend on the quick transfer of electricity. The paper supercapacitor’s high surface-to-volume ratio gives it an advantage.
“This technology has potential to be commercialized within a short time,” said Peidong Yang, professor of chemistry at the University of California-Berkeley. “I don’t think it will be limited to just energy storage devices,” he said. “This is potentially a very nice, low-cost, flexible electrode for any electrical device.”
Cui predicts the biggest impact may be in large-scale storage of electricity on the distribution grid. Excess electricity generated at night, for example, could be saved for peak-use periods during the day. Wind farms and solar energy systems also may require storage.
“The most important part of this paper is how a simple thing in daily life — paper — can be used as a substrate to make functional conductive electrodes by a simple process,” Yang said. “It’s nanotechnology related to daily life, essentially.”
Cui’s research team includes postdoctoral scholars Liangbing Hu and JangWook Choi, and graduate student Yuan Yang.
