Gizmorama - April 13, 2015

Good Morning,

A new aluminum battery could revolutionize the future of energy storage and replace alkaline batteries. I think we could all get a charge out of that.

Learn about this and more interesting stories from the scientific community in today's issue.

Until Next Time,
Erin

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*-- Stanford scientists offer promising new aluminum battery --*
PALO ALTO, Calif. (UPI) - A newly developed aluminum battery could serve as a safer, high-performance alternative to today's alkaline battery. The developers of the new energy storage device say it is the first aluminum-based battery capable of quickly storing and releasing energy.

"We have developed a rechargeable aluminum battery that may replace existing storage devices, such as alkaline batteries, which are bad for the environment, and lithium-ion batteries, which occasionally burst into flames," Hongjie Dai, a chemistry professor at Stanford University, said in a press release. "Our new battery won't catch fire, even if you drill through it."

Aluminum has long been targeted as an ideal element for energy storage. Its high-energy capacity, inflammability and low price make it ideal. The trouble for engineers has been finding the right material to pair with aluminum, a material capable of producing high voltage -- especially after multiple cycles of rapid charging and discharging.

Researchers at Stanford happened upon graphite as the ideal accompaniment. The new aluminum-ion battery's anode is made of aluminum and the cathode of graphite.

"People have tried different kinds of materials for the cathode," Dai explained. "We accidentally discovered that a simple solution is to use graphite, which is basically carbon. In our study, we identified a few types of graphite material that give us very good performance."

The two components are situated in a flexible polymer-coated pouch filled with an ionic liquid electrolyte.

In addition to being inflammable and fast-charging -- scientists suggest the new battery could charge a smartphone in less than 60 seconds -- it is also durable and flexible.

Whereas other aluminum batteries lose their storage capabilities after a few hundred charge-and-release cycles, Dai and his colleagues say their new battery can charge and release its energy some 7,500 times before it loses any capacity.

"Our battery produces about half the voltage of a typical lithium battery," Dai said. "But improving the cathode material could eventually increase the voltage and energy density."

"Otherwise, our battery has everything else you'd dream that a battery should have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life," Dai added. "I see this as a new battery in its early days. It's quite exciting."

In addition to making small electronics more efficient and safe, the battery could also help electrical grids store large amounts of renewable energy.

The new battery is set to be detailed this week in the early online edition of the science journal Nature.


*-- New magnetic field detector could improve medical imaging --*
BOSTON (UPI) - Researchers at MIT say they've designed a hyper-sensitive magnetic field detector that could be used to improve medical imaging technologies and more effectively identify contraband at security checkpoints.

Magnetic field detectors, or magnetometers, are used for metal detection, medical imaging and geological observation, but the devices as currently designed have limitations. Many require "buffer gas" chambers filled with caesium vapor, which are hefty and expensive. Some work within only a narrow frequency range.

The new device, detailed in the latest issue of Nature Physics, attempts to improve upon a magnetometer technique using synthetic diamonds.

A tiny synthetic diamond -- smaller than one-twelfth of a thumbnail -- contains trillions of minuscule defects called nitrogen vacancies (NVs). When NVs are hit with lasers, the light is absorbed and re-emitted by the nano-sized deficiencies. The light, bounced back by NVs, carried information about magnetic fields nearby.

Despite the promise of synthetic diamond chips, organizing this complex process in a compact and efficient device has proven difficult. In previous models, the process of tagging the diamonds with laser photons had proven largely inefficient. Much of the light is launched straight through the diamond, failing to become captured by one of the NVs.

Researchers at MIT found that they if they could shape and angle both the laser and diamond chip just right, they could force the laser photons to bounce around the prism until all of the light was absorbed by NVs. Their technique sees a angled laser beam shot into a sawed-off corner to square-like diamond chip.

"We gain an enormous advantage by adding this prism facet to the corner of the diamond and coupling the laser into the side," Hannah Clevenson, a graduate student in electrical engineering, explained in a recent press release. "All of the light that we put into the diamond can be absorbed and is useful."

The researchers say their newly designed synthetic diamond chip is 1,000 times more efficient than older models.

"What's cool about this is that they're using the sample itself kind of like a waveguide, to bounce the light around," Frank Narducci, a physicist at the U.S. Naval Air Systems Command, told MIT. "Their sample is quite small. Because the laser doesn't have to be anything particularly special, that could be small, too. So you could envision very small magnetometers. And correspondingly, you could make them very cheap."

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