Stories tagged Rice University

Jul
18
2012

Sprayable Battery: Move over spray-tan, there's a new aerosol in town.
Sprayable Battery: Move over spray-tan, there's a new aerosol in town.Courtesy Alex Walker
Researchers from Rice University have rethought the battery. Typically, batteries are made up of 5 layers: a positive and negative electrode, each with a metal current collector, and a polymer separator. These layers are manufactured in sheets and then rolled into cylinders. Rice researchers realized that each of these layers were available, or could be created, in sprayable form. They used lithium titanium oxide and lithium cobalt oxide for the anode and cathode, existing metallic paints and carbon nanotube mixtures for the current collectors, and a chemical hodge-podge with a very lengthy name for the separator layer. The result is an ultra thin (a fraction of a millimeter thick) lithium ion battery.
In their first experiment, researchers sprayed each consecutive layer onto nine bathroom tiles, topped with a solar cell. The resulting batteries were able to power 40 LEDs for six hours.
In its current state, this method is too toxic to be used outside a controlled environment, but with a little tweaking, a safe alternative will be found. At that point, any surface could be a battery!

Jun
28
2012

Sensing Strain: This new system will allow you to detect strain anywhere, in any direction, and at any time.
Sensing Strain: This new system will allow you to detect strain anywhere, in any direction, and at any time.Courtesy Bruce Weisman
Scientists at Rice University developed a new type of paint, infused with carbon nanotubes, that can detect strain in bridges, buildings, and airplanes before the signs of deformation become visible to the naked eye.

This is how it works: The paint is applied to the desired structure and allowed to dry. A laser beam is then focused on the structure, which excites the carbon nanotubes, and in turn, causes them to fluoresce in a way that indicates strain. Finally, a handheld infrared spectrometer is used to measure this fluorescence.

The advantage of strain paint over conventional strain gauges is that the gauge (the paint, in this case) and the read-out device don't have to be physically connected. Also, strain paint allows you to measure strain anywhere on the structure, and along any direction. This product is not yet on the market, but it will benefit all of us, as I'm sure we all find the structural integrity of our planes, bridges, and buildings to be pretty important.

Nano car is molecular in size: 1/20,000th the size of a hair
Nano car is molecular in size: 1/20,000th the size of a hairCourtesy James Tour group

Nanocar is too small to see

James Tour, a professor of chemistry at Rice University, won the Foresight Institute Feynman Prize for experimental nanotechnology for his nanocar, which is four nanometers across and includes a chassis with an engine, a pivoting suspension and rotating axles attached to rolling buckyball wheels, each made of 60 carbon atoms. (click link in red to learn more about smallest car in the world)

Dec
28
2008

Graphene memory is smaller

Graphene transistors: Graphene is an atomic-scale chicken wire made of carbon atoms.
Graphene transistors: Graphene is an atomic-scale chicken wire made of carbon atoms.Courtesy Carbophiliac
Computer memory devices become cheaper, faster, and smaller every year. A team of researchers at Rice University led by James Tour has found a method of creating a new type of memory from a strip of graphite only 10 atoms thick. Individual memory bits smaller than 10 nanometers that have only two terminals will allow super thin sheets of memory to be stacked in layers, multiplying the storage capacity.

Graphene memory is resistant to heat and cold

The graphene memory is able to operate in a very wide temperature range. The researchers have tested the system to minus 75 to over 200 degrees Celsius.

Graphene memory is faster and lasts longer

Researchers say that the new switches are faster than the lab's testing equipment can measure and they promise long life as well.

"We’ve tested it in the lab 20,000 times with no degradation,” said Tour. “Its lifetime is going to be huge, much better than flash memory."

Graphene memory is cheap and easy to produce

"The processes uses graphene deposited on silicon via chemical vapor deposition making for easy construction that can be done in commercial volumes with methods already available," says Tour.

Abstract of Rice University article in Nature

Here, we report that two-terminal devices consisting of discontinuous 5–10 nm thin films of graphitic sheets grown by chemical vapour deposition on either nanowires or atop planar silicon oxide exhibit enormous and sharp room-temperature bistable current–voltage behaviour possessing stable, rewritable, non-volatile and non-destructive read memories with on/off ratios of up to 107 and switching times of up to 1 mus (tested limit). Nature Materials

Source: Rice University News