Flexible 3D graphene supercapacitors may power portables and wearables

Kurzweil AI - Mon, 09/02/2015 - 6:06pm

Laser-induced graphene supercapacitor (credit: Jhiwei Peng et al./Applied Materials and Interfaces)

Rice University scientists have advanced their recent development of laser-induced graphene (LIG) by producing and testing stacked, three-dimensional supercapacitors — energy-storage devices that are important for portable, flexible electronics.

The Rice lab of chemist James Tour discovered last year that firing a laser at an inexpensive polymer burned off other elements and left a film of porous graphene, the much-studied atom-thick lattice of carbon.

The researchers viewed the porous, conductive material as a perfect electrode for supercapacitors or electronic circuits.

To prove it, members of the Tour group have since extended their work to make vertically aligned supercapacitors with laser-induced graphene on both sides of a polymer sheet. The sections are then stacked with solid electrolytes in between for a multilayer sandwich with multiple microsupercapacitors.

Combining energy and power density

The flexible stacks show excellent energy-storage capacity and power potential and can be scaled up for commercial applications. LIG can be made in air at ambient temperature, perhaps in industrial quantities through roll-to-roll processes, Tour said.

The research was reported in Applied Materials and Interfaces.

A schematic shows the process developed by Rice University scientists to make vertical microsupercapacitors with laser-induced graphene. The flexible devices show potential for use in wearable and next-generation electronics. (Credit: Tour Group/Rice University)

Capacitors use an electrostatic charge to store energy they can release quickly, to a camera’s flash, for example. Unlike chemical-based rechargeable batteries, capacitors charge fast and release all their energy at once when triggered.

But chemical batteries hold far more energy. Supercapacitors combine useful qualities of both — the fast charge/discharge of capacitors (power density) and high-energy capacity of batteries (energy density) — into one package.

Tour said that while thin-film lithium ion batteries are able to store more energy, LIG supercapacitors of the same size offer three times the performance in power (the speed at which energy flows). And the LIG devices can easily scale up for increased capacity.

“We’ve demonstrated that these are going to be excellent components of the flexible electronics that will soon be embedded in clothing and consumer goods,” he said.


LIG supercapacitors appear able to do all that with the added benefits of flexibility and scalability. The flexibility ensures they can easily conform to varied packages (they can be rolled within a cylinder, for instance) without giving up any of the device’s performance.

“What we’ve made are comparable to microsupercapacitors being commercialized now, but our ability to put devices into a 3D configuration allows us to pack a lot of them into a very small area,” Tour said.

An electron microscope image shows the cross section of laser-induced graphene burned into both sides of a polyimide substrate. The flexible material created at Rice University has the potential for use in electronics or for energy storage. (Credit: Tour Group/Rice University)

“The other key is that we’re doing this very simply. Nothing about the process requires a clean room. It’s done on a commercial laser system, as found in routine machine shops, in the open air.”

Ripples, wrinkles and sub-10-nanometer pores in the surface and atomic-level imperfections give LIG its ability to store a lot of energy. But the graphene retains its ability to move electrons quickly and gives it the quick charge-and-release characteristics of a supercapacitor.

In testing, the researchers charged and discharged the devices for thousands of cycles with almost no loss of capacitance. The vertical supercapacitors also showed almost no change in electrical performance when flexed, even after 8,000 bending cycles.

The Air Force Office of Scientific Research and its Multidisciplinary University Research Initiative (MURI) and the Office of Naval Research MURI supported the research.

Abstract of Flexible and stackable laser induced graphene supercapacitors

In this paper, we demonstrate that by simple laser induction, commercial polyimide films can be readily transformed into porous graphene for the fabrication of flexible, solid-state supercapacitors. Two different solid-state electrolyte supercapacitors are described, namely vertically stacked graphene supercapacitors and in-plane graphene microsupercapacitors, each with enhanced electrochemical performance, cyclability, and flexibility. Devices with a solid-state polymeric electrolyte exhibit areal capacitance of >9 mF/cm2 at a current density of 0.02 mA/cm2, over twice that of conventional aqueous electrolytes. Moreover, laser induction on both sides of polyimide sheets enables the fabrication of vertically stacked supercapacitors to multiply its electrochemical performance while preserving device flexibility.

Categories: Science

Restoring This WWII B-29 Bomber Has Taken 300K Hours So Far

Wired News - Mon, 09/02/2015 - 6:06pm

Restoring a WW2-era B-29 bomber to flying condition is no easy task.

The post Restoring This WWII B-29 Bomber Has Taken 300K Hours So Far appeared first on WIRED.

Categories: Science

How Millennials Are Changing Product Development for Good

Wired News - Mon, 09/02/2015 - 5:36pm

Like most of you, I’ve read dozens of articles over the past few years about all the ways millennials are different from previous generations: as employees, as consumers, and as innovators. But it wasn’t until last summer, while meeting with a tech startup founded by a team of entrepreneurs in their early 30s, that I […]

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Categories: Science

The Prickly Partnership Between Uber and Google

Slashdot - Mon, 09/02/2015 - 5:35pm
HughPickens.com writes Google, with billions of dollars in the bank and house-by-house maps of most of the planet, seemed like the perfect partner for Uber, the hugely popular ride-hailing service. But Mike Isaac writes in the NYT that just two years after Google's venture capital arm poured more than $250 million into Uber there are signs that the companies are more likely to be ferocious competitors than allies. Uber recently announced plans to develop self-driving cars, a longtime pet project at Google. Travis Kalanick, Uber's CEO, has publicly discussed what he sees as the inevitability of autonomous taxis, saying they could offer cheaper rides and a true alternative to vehicle ownership. "The Uber experience is expensive because it's not just the car but the other dude in the car," Kalanick said at a technology conference in 2014, referring to the expense of paying human drivers. "When there's no other dude in the car, the cost [of taking an Uber] gets cheaper than owning a vehicle." Uber is also adding engineers who are experts on mapping technology. And the company, based in San Francisco, has been in talks with Google's advertising archrival, Facebook, to find ways to work together. Not to be outdone, Google has been experimenting with a ride-sharing app similar to Uber's and both companies have long toyed with the idea of offering same-day delivery of items like groceries and other staples. Last month Google announced it would start presenting data from third party applications inside Google Now, a service that displays useful information prominently on the screen of Android smartphones. Google said it had struck deals to draw data from such apps as Pandora, AirBnb, Zillow, and the ride-sharing service Lyft. The company most obviously missing from that list? Google's old and possibly former friend, Uber. According to Isaac, for young companies, even one as well funded as Uber, dancing with giants is a part of doing business — even if there is always a risk of getting squashed. "There are some hard lessons about the dangers of cooperation that are strongly in the memories of these companies," says John Morgan. "Something that makes partnering harder, even when it might make economic sense to do so."

Read more of this story at Slashdot.

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Origins of colorectal cancer tumor cells traced

Science Daily - Mon, 09/02/2015 - 5:28pm
For the first time, cancer researchers have traced the origins of colorectal cancer cells, finding important clues to why tumor cells become 'good' or 'bad,' with the potential of stopping them before they start.
Categories: Science

Sunlight and vitamin D levels higher for coastal populations

Science Daily - Mon, 09/02/2015 - 5:28pm
People living close to the coast in England have higher vitamin D levels than inland dwellers. Exposure to sunlight is a crucial factor in vitamin D production and the research has also found that English coasts tend to see a greater amount of sunlight across the year when compared with inland areas. The study is the first time that data on sunlight and vitamin D levels have been linked to detailed geographical information.
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Doctor Who LEGO Set to Send Time Lord to LEGO Land

Space.com - Mon, 09/02/2015 - 5:23pm
Doctor Who wins fan-voting contest for LEGO set.
Categories: Science

Sling TV Launches Today, Streaming Tons of Shows at Basic-Cable Prices

Wired News - Mon, 09/02/2015 - 5:15pm

The new Sling TV service offers a $20-per-month package of live and on-demand programming, as well as extra packages for sports, news, and kids' shows.

The post Sling TV Launches Today, Streaming Tons of Shows at Basic-Cable Prices appeared first on WIRED.

Categories: Science

A caring robot with ‘emotion’ and memory

Kurzweil AI - Mon, 09/02/2015 - 5:06pm

(Credit: University of Hertfordshire)

Researchers at the University of Hertfordshire have developed a prototype of a social robot that supports independent living for the elderly, working in partnership with their relatives or carers.

Farshid Amirabdollahian, a senior lecturer in Adaptive Systems at the university, led a team of nine partner institutions from five European countries as part of the €4,825,492 project called ACCOMPANY (Acceptable Robotics Companions for Ageing Years).

“This project proved the feasibility of having companion technology, while also highlighting different important aspects such as empathy, emotion, social intelligence as well as ethics and its norm surrounding technology for independent living,” Amirabdollahian said.

Fraunhofer IPA | ACCOMPANY — Integrated robot technologies for supporting elderly people in their homes

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Report: Automakers Fail To Fully Protect Against Hacking

Slashdot - Mon, 09/02/2015 - 4:51pm
An anonymous reader writes with news about a report by Senator Edward Markey on the security of new vehicles. "Automakers are cramming cars with wireless technology, but they have failed to adequately protect those features against the real possibility that hackers could take control of vehicles or steal personal data, a member of the U.S. Senate is asserting. Basing his argument on information provided by manufacturer, Sen. Edward Markey has concluded that "many in the automotive industry really don't understand what the implications are of moving to this new computer-based era" of the automobile. The Massachusetts Democrat has asked automakers a series of questions about the technologies — and any safeguards against hackers — that may or may not have been built into the latest models of their vehicles. He also asked what protections have been provided to ensure that information computers gather and often transmit wirelessly isn't used in a harmful or invasive manner."

Read more of this story at Slashdot.

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Will Oculus Rift Help or Hinder Traditional Tourism?

Wired News - Mon, 09/02/2015 - 4:48pm

Virtual reality technology is changing, and fast. Soon to hit the market, Oculus Rift is a virtual reality headset which is worn like a pair of oversized goggles and, while still being refined, is already available to the public. Made to connect to computers and mobile devices, it gives users a 3D experience and allows […]

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Categories: Science

World thunderstorm 'map' key to assessing climate change

Science Daily - Mon, 09/02/2015 - 4:32pm
New research will likely be crucial to measuring the impact of climate change on thunderstorms -- one of the weather occurrences most problematic for human life on the planet. The varying frequency and intensity of thunderstorms have direct repercussions for the public, agriculture, and industry.
Categories: Science

Controlling genes with light: Light-activated genes might be precisely controlled and targeted

Science Daily - Mon, 09/02/2015 - 4:32pm
Researchers have demonstrated a new way to activate genes with light, allowing precisely controlled and targeted genetic studies and applications. The method might be used to activate genes in a specific location or pattern, allowing more precise study of gene function, or to create complex systems for growing tissue or new therapies.
Categories: Science

Earth's surprise inside: Geologists unlock mysteries of the planet's inner core

Science Daily - Mon, 09/02/2015 - 4:32pm
Seismic waves are helping scientists to plumb the world's deepest mystery: the planet's inner core. Thanks to a novel application of earthquake-reading technology, researchers have found that the Earth's inner core has an inner core of its own, which has surprising properties that could reveal information about our planet.
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Evidence for dark matter in the inner Milky Way

Science Daily - Mon, 09/02/2015 - 4:30pm
A new study is providing evidence for the presence of dark matter in the innermost part of the Milky Way, including in our own cosmic neighborhood and the Earth's location. The study demonstrates that large amounts of dark matter exist around us, and also between us and the Galactic center. The result constitutes a fundamental step forward in the quest for the nature of dark matter.
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A centimeter of time: Cool clocks pave the way to new measurements of Earth

Science Daily - Mon, 09/02/2015 - 4:30pm
Two cryogenically cooled optical lattice clocks that can be synchronized to a tremendous one part in 2.0 x 10-18--meaning that they would only go out of synch by a second in 16 billion years. This is nearly 1,000 times more precise than the current international timekeeping standard cesium atomic clock.
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Stellar partnership doomed to end in catastrophe

Science Daily - Mon, 09/02/2015 - 4:30pm
Astronomers have identified two surprisingly massive stars at the heart of the planetary nebula Henize 2-428. As they orbit each other the two stars are expected to slowly get closer and closer, and when they merge, about 700 million years from now, they will contain enough material to ignite a vast supernova explosion.
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Pick a card, any card: How magicians sway decision-making

Science Daily - Mon, 09/02/2015 - 4:30pm
A team of Canadian researchers has combined the art of magic and the science of psychology to demonstrate how certain contextual factors can sway the decisions people make, even though they may feel that they are choosing freely.
Categories: Science

Both Liberals, Conservatives Can Have Science Bias

Science Daily - Mon, 09/02/2015 - 4:30pm
New research suggests that liberals, as well as conservatives, can be biased against science that doesn’t align with their political views.
Categories: Science

Senate Report Slams Automakers for Leaving Cars Vulnerable to Hackers

Wired News - Mon, 09/02/2015 - 4:11pm

A new senate report reveals that most modern cars are vulnerable to hacking and that the industry is not even close to having a grasp on what to do about it.

The post Senate Report Slams Automakers for Leaving Cars Vulnerable to Hackers appeared first on WIRED.

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