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The Aqueous Storage Device That Needs Just 20 Seconds to Charge

The Aqueous Storage Device

The Aqueous Storage Device That Needs Just 20 Seconds to Charge


A KAIST research team developed a new hybrid energy aqueous storage device that can be charged in less than half a minute. It employs aqueous electrolytes instead of flammable organic solvents, so it is both environmentally friendly and safe. It also facilitates a boosting charge with high energy density, which makes it suitable for portable electronic devices.

Professor Jeung Ku Kang and his team from the Graduate School of Energy, Environment, Water, and Sustainability developed this hybrid energy storage with high energy and power densities over a long cycle life by assembling fiber-like polymer chain anodes and sub-nanoscale metal oxide cathodes on graphene.

Conventional aqueous electrolyte-based energy storage devices have a limitation for boosting charges and high energy density due to low driving voltages and a shortage of anode materials.

Energy storage device capacity is determined by the two electrodes, and the balance between cathode and anode leads to high stability. In general, two electrodes show differences in electrical properties and differ in ion storage mechanism processes, resulting in poor storage and instability from the imbalance.

The research team came up with new structures and materials to facilitate rapid speed in energy exchange on the surfaces of the electrodes and minimize the energy loss between the two electrodes.

The team made anodes with graphene-based polymer chain materials. The web-like structure of graphene leads to a high surface area, thereby allowing higher capacitance.

For cathode materials, the team used metal oxide in sub-nanoscale structures to elevate atom-by-ion redox reactions. This method realized higher energy density and faster energy exchange while minimizing energy loss.

New aqueous storage device can be quickly charged

The developed device can be charged within 20 to 30 seconds using a low-power charging system, such as a USB switching charger or a flexible photovoltaic cell. The developed aqueous hybrid energy device shows more than 100-fold higher power density compared to conventional aqueous batteries and can be rapidly recharged.

Further, the device showed high stability with its capacity maintained at 100 percent at a high charge/discharge current. Professor Kang said:

This research, led by Ph.D. candidate Il Woo Ock, was published in Advanced Energy Materials on January 15.

Provided by: Korea Advanced Institute of Science and Technology [Note: Materials may be edited for content and length.]

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Project Acoustic Kitty: The CIA and Their Cat Spy

The CIA's 'Acoustic Kitty' cat spy. (Image: Screenshot via YouTube)


During the height of the Cold War, officials in the CIA devised a covert plan to keep tabs on Russians in Washington, D.C. As part of a clandestine experiment, “Project Acoustic Kitty” was launched by the Central Intelligence Agency Directorate of Science & Technology, which cost more than $20 million over five years in the 1960s.

In unclassified documents, it has been revealed that unlucky felines were cut open and stuffed with electronic hardware. That’s right, cats were actually surgically implanted with microphones, radio transmitters, and batteries.

Cats are infamously disobedient; however, scientists at the CIA believed that with the right training, “Acoustic Kitty” could become a spy. It wasn’t an easy task in an era of reel-to-reel audio recording and room-sized computers, and for this to work, the cat had to still look like a cat. Five years on and they were finally ready.

The CIA built a 3/4-inch (0.72mm) long transmitter to embed at the base of the cat’s skull. A microphone was placed in the ear canal; the antenna was made from fine wire and woven all the way to the tail through the cat’s long fur to conceal it. The batteries had to be small; this restricted the amount of time the cat would be able to record.

The aim in using a cat was to exploit one of the animal’s main traits — curiosity. It was thought that a cat wired to record sound would be able to come and go unnoticed, and with the use of audio cues, could be controlled to go where it would record interesting sounds — like eavesdropping on activity at the Soviet Embassy.

However, in the test, there was just no controlling the “Acoustic Kitty.” It would simply wander off when it got bored, distracted, or hungry. The cat’s hunger issues were quickly addressed with yet another operation. The additional surgical and training expenses brought the total cost up to $20 million, but “Acoustic Kitty” was finally ready for is first mission.

Acoustic Kitty’s first mission

In 1966, “Acoustic Kitty” was given its first mission in Washington, D.C. Its target was two men sitting on a bench in the park just outside the Soviet Embassy on Wisconsin Avenue. CIA agents released their rookie agent from a nondescript van filled with electronic surveillance equipment and scientists who were watching on eagerly, excited to be a part of history.

“Acoustic Kitty” dashed off toward the embassy, however in just 10 feet, it was unceremoniously struck by a passing taxi and killed while crossing the road. Victor Marchetti, who was an executive assistant to the director of the CIA in the 1960s, recalled in a statement:

In the aftermath of the disastrous experiment, Operation Acoustic Kitty was scrapped in 1967, along with the remains of “Acoustic Kitty.” The CIA concluded in a heavily-redacted memo titled “Views on Trained Cats” held in the National Security Administration archive at George Washington University that the project wasn’t a total failure:

It also states that despite the “energy and imagination” of those involved, it “would not be practical” to continue to try to train cats as spies. So next time your cat walks up to you for an afternoon nap, it may actually be trying to steal your secrets.

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