Nanotube batteries on paper

dustindriver | Categroies: Engineering, Environment, Gadgets, Green Tech, Transportation | Tags: , , | Wednesday, March 3rd, 2010

In case you missed it, the geniuses at Stanford have created super batteries using carbon nanotube ink and silver nanowires. They basically spread the carbon nanotube/silver goop on paper and it’s ready to store energy. The paper batteries are capable of storing 10 times as much energy by weight as lithium-ion batteries and are conceivably good for 40,000 charge-discharge cycles. From the Stanford article:

“These nanomaterials are special,” [assistant professor Yi] 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 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.

Cui says that the thin, lightweight, flexible batteries could be used in everything from consumer electronics to cars. He also says the technology is basically ready for action. Just a few refinements and the batteries could go into production.

Link to Stanford article

Bio-cell batteries for nanobots

dustindriver | Categroies: Biology, Engineering, Green Tech, Nanotech | Tags: , , , , | Tuesday, October 27th, 2009

If you’re going to build a swarm of nanobots to take over the world, you’ll need a lot of very tiny batteries. You could build microscopic AAs with exceedingly diminutive tools, or turn to the best nano-scale builder known: Nature. Scientists at Yale were studying how some cells turn chemical energy into electrical energy (brain cells, the cells that give electric eels their zap) when they inadvertently created synthetic cell batteries.

The simple cells are essentially lipid sacks filled with salt water and a modified protein. When two of the synthetic cells touch, they stick together. The proteins create pores between the two cells. If the two cells have different salt concentrations, positive or negative ions will pass through the pores shared wall until salt concentrations in both cells reach an equilibrium. Stick the cells with electrodes to siphon off the ions and you’ve got a microscopic battery.

Two 200-nanoliter drops of the cells in solution can deliver electricity for about 10 minutes. An 11-microleter volume can put out a charge for more than four hours.

Researchers say the cells turn chemical energy into electrical energy at about 10 percent efficiency, which is frankly pretty terrible for a battery. But it’s pretty good when compared to tiny solar cells or piezoelectric devices that generate electricity from mechanical stress.

Link to Gizmag article

Lithium-sulphur batteries: Triple the charge

dustindriver | Categroies: Engineering, Gadgets, Green Tech, Nanotech | Tags: , , , , , | Wednesday, September 30th, 2009

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Batteries seem to be stuck in the days of Edison—heavy, toxic bricks that hold measly amounts of energy and wear out far too quickly. Even hallowed lithium-ion batteries are expensive and unstable. Thankfully the next generation of batteries are on the horizon, and they’re hellishly awesome.

Engineers at the University of Waterloo in Canada have revived lithium-sulphur batteries. They promise to pack three times as much power as lithium-ion batteries, and weigh much less than current power cells.

Lithium-sulphur batteries aren’t anything new. They were developed ages ago, but abandoned due to high cost, poor efficiency, and short lifespan. Charging and discharging a lithium-sulphur battery involves moving lithium ions between two electrodes within the battery. Theoretically, sulphur should be able to hold twice as many lithium ions. But sulphur is an insulator, making it difficult for electrons and ions to move freely into and out of the sulphur electrode.

The scientists at Waterloo have overcome the technical issues using a nanostructure of carbon rods. Sulphur is melted into the carbon nanostructure, giving ions much better access to the sulphur. Essentially, ions and electrons can travel down the carbon rods to reach the sulphur melted between them.

The battery is in testing phases right now, which means we’ll likely not see lithium-sulphur batteries in laptops, iPods, or electric cars for a few years.

Link to Gizmodo article

Link to Technology Review article

Electrifying new battery tech

dustindriver | Categroies: Computing, Engineering, Gadgets, Green Tech, Nanotech, Renewable Energy | Tags: , , , | Thursday, April 30th, 2009

The automotive future is electric. But if we want to chuck fossil-fuel-chugging cars into the recycling bin, we’ll need better batteries. Two new developments in battery tech could make electric transportation feasible.

A team at the University of Maryland has developed a new breed of supercapacitor that could replace conventional batteries in electric cars. The new supercapacitors can store as much juice as the best batteries, but deliver that juice as quickly as a capacitor.

It’s a big deal, especially for electric cars. To get an electric car to burn rubber (accelerate briskly), you need a lot of current, quickly. Batteries can’t do it without the help of capacitors—the superchargers of the electrical world. Capacitors store energy on the surface of two plates separated by an insulator. They store and release electricity much faster than batteries.

The team at the University of Maryland joined forces with engineers at the Korea Advanced Institute of Science and Technology to create a grid of nano capacitors. Their prototype contains more than 10 billion nano capacitors linked together with electrodes. And they did it on aluminum foil.

Gary Rubloff, a physicist at the University of Maryland, anodized (added a layer of oxide) a sheet of foil to create a uniform grid of nanopores. Using atomic layer deposition, the team filled the pores with three layers of material that mimic the conductor-insulator-conductor layout of a normal capacitor.

A kilogram of the new supercapacitor could deliver a megawatt of power—enough to power 10,000 100-watt light bulbs.

Whiz kids at MIT have also found a way to make lithium batteries speedier. Gerbrand Ceder, the Richard P. Simmons Professor of Materials Science and Engineering at MIT, has drastically improved the charge and discharge rate of lithium batteries by redesigning their structure.

Everyday lithium batteries store tons of energy, but they can’t absorb or discharge it very quickly. Turns out that the slow charge/discharge rate is due to a kind of atomic traffic jam. Charged ions get gummed up traveling in and out of the battery.

Ceder and grad student Byoungwoo Kang found that they could fee up the traffic jam by engineering a beltway of material around the battery. The result is a small battery that can be charged and discharged between 10 and 20 seconds. The discovery should lead to faster-charging gadgets and quick recharges for electric vehicles.

Link to NewScientist article

Link to MIT article

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