Saturday, October 19, 2013

AT&T intros more flexible day pass and three-month tablet data plans

AT&T pushes cellular data on tablets, introduces more flexible day pass and three-month plans

AT&T has introduced two new data plans for tablets, a lower-cost day pass and a three-month plan. The day pass costs $5 and gives you 250MB of data for 24 hours, while the three-month plan, aimed at infrequent users of cellular data, will cost $25 and give you 1GB for three months. AT&T says that it's all about getting customers interested in buying cellular-equipped tablets, according to Ina Fried at All Things D:

“We really think that a Wi-Fi only tablet is good, but it is not good enough,” said AT&T senior VP Chris Penrose, speaking at the event. The cost of adding a cellular module to tablets is also going down, Penrose said.

Customers have so far preferred Wi-Fi-only tablets to the cellular models, likely due to cost. The cellular versions of all of Apple's iPads cost an extra $130 over their Wi-Fi-only counterparts. AT&T hopes that cellular radios will just be standard in all tablets soon, instead of having separate Wi-Fi and cellular versions.

It's not hard to see why AT&T is pushing for cellular tablets. AT&T is undoubtedly hoping that many people will eventually add tablets to their mobile share plans, which include a monthly device fee. But even if customers buy a Wi-Fi-only iPad, they may want to tether it to their phone when on the go, which in turn could get them to buy more data for their plan, a win-win for AT&T.

Will you try out one of these plans? Let us know in the comments below.

Source: All Things D

AT&T coverage map


    






Source: http://feedproxy.google.com/~r/TheIphoneBlog/~3/CuabLjJsmBM/story01.htm
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Overnight dialysis boosts kidney health -- while reducing risk of heart disease

Overnight dialysis boosts kidney health -- while reducing risk of heart disease


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PUBLIC RELEASE DATE:

18-Oct-2013



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Contact: Jane Diane Fraser
jfraser@hsf.ca
613-569-4361 x273
Heart and Stroke Foundation of Canada



Treatment shows promise for improving artery function




Montreal Receiving dialysis at home while sleeping not only improves kidney health and quality of life for people with kidney disease, it could also decrease their risk of heart disease, says new study presented at the Canadian Cardiovascular Congress.


"Patients with end-stage renal disease have at least a five-fold increase in cardiovascular complications," says Dr. Christopher Overgaard, one of the study's authors and a cardiologist at the Toronto General Hospital. "Longer dialysis, done while patients are sleeping, may improve the health of arteries and could lower the risk of developing heart disease."


The study found that after patients transitioned to overnight dialysis, there were improvements in coronary artery function.


Because of the frequency and duration of overnight dialysis, toxins are more evenly and gently removed from the blood. "Increasing the number of hours patients receive their treatment results in less toxin buildup in their blood for shorter durations," says Dr. Overgaard.


Impaired endothelial function a condition that reduces blood vessel's ability to dilate puts kidney patients at a significantly higher risk for the development of atherosclerosis (the buildup of fat in the walls of arteries). Atherosclerosis, in turn, can eventually lead to serious problems including heart attacks, stroke or even death.


Conventional hemodialysis in a clinic typically involves dialysis three times a week, for three to four hours at a time upwards of 12 hours a week.


Contrast that with what's called overnight "home" hemodialysis, done while patients sleep at home. This method allows dialysis six times a week, for up to 12 hours at a time, for up to 72 hours.


Beyond the clinical benefits, patients on overnight dialysis no longer have to revolve much of their schedule around clinic trips.


"This method also improves quality of life by having the dialysis in the comfort of your home, while sleeping, instead of being stuck in a dialysis unit for hours," says Dr. Overgaard. "Old-fashioned dialysis is stressful."


A dialysis machine functions as a kidney for people whose kidneys aren't functioning properly; in essence, cleaning their blood.


"This could be revolutionary for kidney patients," says Dr. Beth Abramson, Heart and Stroke Foundation spokesperson. "A simple change in the way we deliver care can make a significant difference. In addition to benefits to kidney function and quality of life, it could lower their risk of heart disease."


She adds that high blood pressure and diabetes are two common causes of kidney disease and all Canadians should be mindful of reducing these risks.


The Canadian Cardiovascular Congress is co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.


###

Statements and conclusions of study authors are solely those of the study authors and do not necessarily reflect Vascular 2013 host organizations' policy or position. They make no representation or warranty as to their accuracy or reliability.


The Heart and Stroke Foundation's mission is to prevent disease, save lives and promote recovery. A volunteer-based health charity, we strive to tangibly improve the health of every Canadian family, every day. 'Healthy lives free of heart disease and stroke. Together we will make it happen.' Heartandstroke.ca


HSF spokesperson Beth Abramson is the author of the newly released book Heart Health for Canadians.


Vascular 2013 is a unique, one-time Canadian event bringing four separate scientific meetings together under one roof: the Canadian Cardiovascular Congress, the Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism Professional Conference, the Canadian Stroke Congress and the Canadian Hypertension Congress. vascular2013.ca


It is a joint initiative of the Canadian Cardiovascular Society, Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism, the Canadian Stroke Network, the Heart and Stroke Foundation, and Hypertension Canada.


For more information and/or interviews, contact the
VASCULAR 2013 MEDIA OFFICE AT 514-789-3402 (Oct 17-20)


OR


Massy Forget Langlois Public Relations

Christian Ahuet, Consultant

514-842-2455, ext. 29 / Cell. 514-994-7496


Congress information and media registration is at http://www.vascular2013.ca


After October 20, 2013 contact:

Jane-Diane Fraser

Heart and Stroke Foundation

jfraser@hsf.ca

613-569-4361x273




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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.




Overnight dialysis boosts kidney health -- while reducing risk of heart disease


[ Back to EurekAlert! ]

PUBLIC RELEASE DATE:

18-Oct-2013



[


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| Share Share

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Contact: Jane Diane Fraser
jfraser@hsf.ca
613-569-4361 x273
Heart and Stroke Foundation of Canada



Treatment shows promise for improving artery function




Montreal Receiving dialysis at home while sleeping not only improves kidney health and quality of life for people with kidney disease, it could also decrease their risk of heart disease, says new study presented at the Canadian Cardiovascular Congress.


"Patients with end-stage renal disease have at least a five-fold increase in cardiovascular complications," says Dr. Christopher Overgaard, one of the study's authors and a cardiologist at the Toronto General Hospital. "Longer dialysis, done while patients are sleeping, may improve the health of arteries and could lower the risk of developing heart disease."


The study found that after patients transitioned to overnight dialysis, there were improvements in coronary artery function.


Because of the frequency and duration of overnight dialysis, toxins are more evenly and gently removed from the blood. "Increasing the number of hours patients receive their treatment results in less toxin buildup in their blood for shorter durations," says Dr. Overgaard.


Impaired endothelial function a condition that reduces blood vessel's ability to dilate puts kidney patients at a significantly higher risk for the development of atherosclerosis (the buildup of fat in the walls of arteries). Atherosclerosis, in turn, can eventually lead to serious problems including heart attacks, stroke or even death.


Conventional hemodialysis in a clinic typically involves dialysis three times a week, for three to four hours at a time upwards of 12 hours a week.


Contrast that with what's called overnight "home" hemodialysis, done while patients sleep at home. This method allows dialysis six times a week, for up to 12 hours at a time, for up to 72 hours.


Beyond the clinical benefits, patients on overnight dialysis no longer have to revolve much of their schedule around clinic trips.


"This method also improves quality of life by having the dialysis in the comfort of your home, while sleeping, instead of being stuck in a dialysis unit for hours," says Dr. Overgaard. "Old-fashioned dialysis is stressful."


A dialysis machine functions as a kidney for people whose kidneys aren't functioning properly; in essence, cleaning their blood.


"This could be revolutionary for kidney patients," says Dr. Beth Abramson, Heart and Stroke Foundation spokesperson. "A simple change in the way we deliver care can make a significant difference. In addition to benefits to kidney function and quality of life, it could lower their risk of heart disease."


She adds that high blood pressure and diabetes are two common causes of kidney disease and all Canadians should be mindful of reducing these risks.


The Canadian Cardiovascular Congress is co-hosted by the Heart and Stroke Foundation and the Canadian Cardiovascular Society.


###

Statements and conclusions of study authors are solely those of the study authors and do not necessarily reflect Vascular 2013 host organizations' policy or position. They make no representation or warranty as to their accuracy or reliability.


The Heart and Stroke Foundation's mission is to prevent disease, save lives and promote recovery. A volunteer-based health charity, we strive to tangibly improve the health of every Canadian family, every day. 'Healthy lives free of heart disease and stroke. Together we will make it happen.' Heartandstroke.ca


HSF spokesperson Beth Abramson is the author of the newly released book Heart Health for Canadians.


Vascular 2013 is a unique, one-time Canadian event bringing four separate scientific meetings together under one roof: the Canadian Cardiovascular Congress, the Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism Professional Conference, the Canadian Stroke Congress and the Canadian Hypertension Congress. vascular2013.ca


It is a joint initiative of the Canadian Cardiovascular Society, Canadian Diabetes Association/Canadian Society of Endocrinology and Metabolism, the Canadian Stroke Network, the Heart and Stroke Foundation, and Hypertension Canada.


For more information and/or interviews, contact the
VASCULAR 2013 MEDIA OFFICE AT 514-789-3402 (Oct 17-20)


OR


Massy Forget Langlois Public Relations

Christian Ahuet, Consultant

514-842-2455, ext. 29 / Cell. 514-994-7496


Congress information and media registration is at http://www.vascular2013.ca


After October 20, 2013 contact:

Jane-Diane Fraser

Heart and Stroke Foundation

jfraser@hsf.ca

613-569-4361x273




[ Back to EurekAlert! ]

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| Share Share

]

 


AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.




Source: http://www.eurekalert.org/pub_releases/2013-10/hasf-odb101613.php
Tags: What Does Government Shutdown Mean   emily blunt   ellie goulding   Jason Dufner   Ross Lynch  

Japanese kids sing 'Sunny in Philadelphia' tune

TV











8 hours ago

The Internet does not always supply context. But when it offers up a video of adorable Japanese kids singing "The Dayman Song" from "It's Always Sunny in Philadelphia" while standing in front of a whiteboard image of "Family Guy's" Peter Griffin, how much explanation does anyone really need?

The video was first published on YouTube in August, but started taking off virally after being posted as a Reddit link on Monday. Thus far, the video has over 370,000 hits on YouTube. In it, the children stand in a straight line and not only sing the lyrics (a conversation between "The Princess" and "The Dayman") but offer up a little choreography and hand gestures, too. (And if you like that, be sure to check out children rocking out to the Ramones' "Judy Is a Punk," from 2011.)

"Dayman" appeared on "Philadelphia" as part of a musical written by one of the show's characters; on the show, the musical did not go over well. Who knew it could have such a lively second life on the other side of the world from Philly?








Source: http://www.today.com/entertainment/japanese-kids-sing-its-always-sunny-philadelphia-tune-8C11393572
Tags: 911   amc   raven symone   Eddie Lacy   Alfonso Soriano  

Engadget Mobile Podcast 193 - 10.17.13

Want to go beyond the review for even more details about HTC's One Max? You've come to the right place, as Brad Molen and Richard Lai dive into all the details, from fingerprint scanning to battery life and more. Also on the topic of HTC, you'll find out if Richard got cooties by licking the ...


Source: http://feeds.engadget.com/~r/weblogsinc/engadget/~3/RLoEAhbqspE/
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Friday, October 18, 2013

This Animated Globe Lets You See the Earth Like You Were in Space

When Google Maps can deliver detailed views of the world with imagery that zooms right down to our backyards, they're can't be much demand for desk globes anymore. So a Japanese company called Gakken has taken its Worldeye globe to another level by turning it into a display that can show everything from weather patterns to stars.

Read more...


    






Source: http://feeds.gawker.com/~r/gizmodo/full/~3/YUGV2LDh-Eg/this-animated-globe-lets-you-see-the-earth-like-you-wer-1447859124
Category: hocus pocus   Aaron Alexis   emily blunt   Wrecking Ball   the bachelorette  

Lebanese Shiite pilgrims kidnapped in Syria freed


BEIRUT (AP) — Nine Shiite pilgrims from Lebanon kidnapped in Syria were freed late Friday night as part of a negotiated hostage deal that could see two Turkish pilots held by Lebanese militants released, officials said.

The complicated three-way deal also potentially includes the release of female prisoners now held by the embattled government of Syrian President Bashar Assad. While details about the deal remained murky, it appeared to represent one of the more ambitious negotiated settlements to come out of Syria's civil war, now entering its third year and being fought by forces tearing apart the region and largely opposed to any bartered peace.

The pilgrims were part of a group of 11 hostages taken by a rebel faction in northern Syria in May 2012. Two were later released, but the nine had been held since, causing friction in the region and sparking the August kidnapping in Beirut that saw two Turkish Airlines pilots abducted.

Lebanese Interior Minister Marwan Charbel told The Associated Press that the nine Lebanese hostages "are now in Turkish territories." Charbel said he expects two Turkish pilots to be released in Lebanon soon and the Syrian government will release a number of female detainees.

"We insist that those who kidnapped the Turks release them," Charbel said, referring to the pilots. The two pilots appeared in a video on Wednesday, the first since they were kidnapped.

"This is all part of one deal," Charbel said by telephone.

Asked when he expects the freed Lebanese to come home, he said "in the coming 24 to 48 hours."

In Turkey, the state-run Anadolu Agency quoted Foreign Minister Ahmet Davutoglu as saying "there are positive developments" concerning the hostages and that the issue had "mostly been resolved." The agency did not immediately provide any further details, though a previous story said Turkish Prime Minister Recep Tayyip Erdogan called the wife of one of the kidnapped pilots to say the two would be released soon.

"We are very close to reaching a happy ending, this could happen any time," the agency quoted Erdogan as saying.

The pilgrims were kidnapped in May 2012 while on their way from Iran to Lebanon through Turkey and Syria. Militants kidnapped them shortly after they crossed the Turkish border into Syria. Two of the pilgrims were later released with Turkey's assistance.

In Beirut's southern suburbs, the families of the nine Lebanese gathered Friday night at a travel agency that they went to Iran with, some of them weeping.

The two Turkish Airlines pilots, previously identified as Murat Akpinar and Murat Agca, were kidnapped after flying into Beirut from Istanbul on Aug. 9. Lebanon's state news agency reported that a group called Zuwaar al-Imam Rida claimed responsibility for the kidnapping. The group said the pilots "will only be released when the Lebanese hostages in Syria return," referring to the Shiite pilgrims.

The commander of the rebel brigade that kidnapped the pilgrims, Ammar al-Dadikhi, told the AP last September that he was holding them captive to try to force Lebanon's Shiite militant group Hezbollah to stop supporting Assad's government.

Syria's rebels are predominantly Sunnis, and are widely supported by Lebanon's own Sunni community. Hezbollah fighters have played a critical role in recent battlefield victories for forces loyal to Assad.

Details about the negotiated deal remained vague Friday night, including who was responsible for coordinating across different factions in the Syrian civil war. Satellite news channel Al-Jazeera quoted Qatar's Foreign Minister Khalid bin Mohamed al-Attiyah as saying the tiny Gulf nation negotiated the release of the nine pilgrims.

It also remained unclear what female prisoners the Syrian government would release under any potential deal. Syrian officials could not be immediately reached for comment Friday night.

At least 100,000 Syrians have been killed in the country's civil war, now in its third year. While world powers recently helped negotiate a deal for Syria's stockpile of chemical weapons to be itemized and destroyed, bringing the government and rebel factions to peace talks remains difficult. Syria's government this week floated Nov. 23-24 as possible dates for talks on a political solution to the conflict, though there was no agreement on the ground rules for negotiations and the main Western-backed opposition hasn't decided whether to attend.

Meanwhile, the war continues. Regime forces and Syrian rebels fighting for control of the small but strategic town of Tal Aran in the country's embattled northern province of Aleppo have killed at least 20 people, most of them civilians, activists said Friday. Meanwhile, rebels killed at least 30 Syrian soldiers, including ten who were executed after they were captured, said the British-based Syrian Observatory for Human Rights.

___

Associated Press writers Suzan Fraser in Ankara, Turkey, Jon Gambrell in Cairo and Diaa Hadid in Beirut contributed to this report.

Source: http://news.yahoo.com/lebanese-shiite-pilgrims-kidnapped-syria-freed-203247827.html
Category: Ed Sheeran   dancing with the stars   Lleyton Hewitt   alex rodriguez   Jared Remy  

Why lithium-ion-batteries fail

Why lithium-ion-batteries fail


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PUBLIC RELEASE DATE:

17-Oct-2013



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Contact: Vanessa Wood
wood@iis.ee.ethz.ch
41-446-326-654
ETH Zurich






Lithium-ion batteries are in our cellphones, laptops, and digital cameras. Few portable electronic devices exist that do not rely on these energy sources. Currently battery electrodes contain active materials known as intercalation compounds. These materials store charge in their chemical structure without undergoing substantial structural change. That makes these batteries comparatively long-lived and safe. However, intercalation materials have one drawback: their limited energy density, the amount of energy they can store per volume and mass.


In the search for higher energy density batteries, scientists have experimented for more than 20 years with materials capable of repetitively alloying and de-alloying with lithium. Laboratory-scale experiments have shown that batteries with such materials have energy densities multiple times that of intercalation materials; however, these alloying materials are not yet exploited in industry because their lifetime is limited. Martin Ebner, Ph.D. student at the Laboratory for Nanoelectronics in the Department of Information Technology and Electrical Engineering (D-ITET) explains: "their capacity typically fades after a couple of charging and discharging cycles." This is attributed to a massive up to threefold expansion of the electrode material during charging. During discharge, the materials contract again, but do not reach their original state. Electrode particles break apart, the electrode structure disintegrates, and the fragments loose contact to the rest of the cell.


Batteries x-rayed during operation


To better understand this complex electrochemical and mechanical degradation of the electrode and to gain insight into how to develop better batteries, Martin Ebner and ETH-Professor Vanessa Wood, head of the Laboratory for Nanoelectronics at D-ITET, recognized the need to study a battery electrode non-invasively during operation. To do so, they turned to an imaging tool developed by ETH-Professor Marco Stampanoni. Professsor Stampanoni, holds a faculty position at the Institute for Biomedical Engineering at D-ITET and runs the tomographic x-ray microscopy beamline at the Swiss Light Source, the synchrotron facility at the Paul Scherrer Institute. The spectrally pure and intense synchrotron x-ray radiation enables the fast acquisition of high-resolution x-ray images that can be computationally assembled into three-dimensional movies.


The researchers observed the inside of the battery as it charged and discharged over 15 hours. They gathered unique, three-dimensional movies that capture the degradation mechanisms occurring in the battery and quantified the processes occurring within every particle for the thousands of particles in the electrode. The results of this study will be published in the journal Science; a pre-print version is available online at Science Express.


Irreversible structural changes


The data illustrate that tin oxide (SnO) particles expand during charging due to the influx of lithium ions causing an increase in particle volume. The scientists demonstrate that material lithiation happens as a core-shell process, progressing uniformly from the particle surface to the core. The material undergoing this reaction expands linearly with the stored charge. The x-ray images show that charging destroys the particle structure irreversibly with cracks forming within the particles. "This crack-formation is not random," emphasizes Ebner. Cracks grow at locations where the crystal lattice contains preexisting defects. During discharge, the particle volume decreases; however, the material does not reach its original state again; the process is therefore not completely reversible.


The volume change of the individual particles drives expansion of the entire electrode from 50 micrometers to 120 micrometers. However, during discharge, the electrode contracts only to 80 micrometers. This permanent deformation of the electrode demonstrates that the polymer binder that holds the electrode together is not yet optimized for high volume expansion materials. This is critical for battery performance because deformation of the binder causes individual particles to become disconnected from the electrode and the battery looses capacity.


In addition to demonstrating that x-ray tomographic microscopy provides insight into morphological changes in the particles and electrodes, the researchers show that this technique can also be used to obtain quantitative and spatially resolved chemical information. For example, the researchers analyze chemical composition throughout the battery electrode to look at differences in lithiation dynamics at the single particle level and compare this to the average particle behavior. This approach is essential to understanding the influence of particle size, shape, and electrode homogeneity on battery performance.


Such insights into the operation of a battery would not be possible without the highly advanced x-ray tomography setup at the Swiss Light Source. "Visualizing batteries in operation was essentially impossible until recent advances in x-ray tomography. Thanks to the world class facilities developed by Professor Stampanoni and his team, we can watch the battery at work," adds Wood enthusiastically.


Alternatives to crystalline materials


The researchers chose crystalline tin oxide as a model material because it undergoes a series of complex transformations also present in other materials, enabling deeper understanding into the behavior of a variety of battery materials. The insights provide the basis for developing new electrode materials and electrode structures that are tolerant to volume expansion. For Prof. Wood the results of this work indicate the benefit of using amorphous or nanostructured materials instead of crystalline ones. "On the quest for new materials, one must also bear in mind that they are only of industrial interest if they can be produced in large quantities at a low cost. However, amorphous and nanostructured materials offer a sufficient playground for innovation." emphasizes Wood.


###


Reference


Ebner M, Marone F, Stampanoni M, Wood V. Visualization and quantification of electrochemical and mechanical degradation in Lithium ion batteries. Science Express, published online 17th October 2013.


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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.




Why lithium-ion-batteries fail


[ Back to EurekAlert! ]

PUBLIC RELEASE DATE:

17-Oct-2013



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Contact: Vanessa Wood
wood@iis.ee.ethz.ch
41-446-326-654
ETH Zurich






Lithium-ion batteries are in our cellphones, laptops, and digital cameras. Few portable electronic devices exist that do not rely on these energy sources. Currently battery electrodes contain active materials known as intercalation compounds. These materials store charge in their chemical structure without undergoing substantial structural change. That makes these batteries comparatively long-lived and safe. However, intercalation materials have one drawback: their limited energy density, the amount of energy they can store per volume and mass.


In the search for higher energy density batteries, scientists have experimented for more than 20 years with materials capable of repetitively alloying and de-alloying with lithium. Laboratory-scale experiments have shown that batteries with such materials have energy densities multiple times that of intercalation materials; however, these alloying materials are not yet exploited in industry because their lifetime is limited. Martin Ebner, Ph.D. student at the Laboratory for Nanoelectronics in the Department of Information Technology and Electrical Engineering (D-ITET) explains: "their capacity typically fades after a couple of charging and discharging cycles." This is attributed to a massive up to threefold expansion of the electrode material during charging. During discharge, the materials contract again, but do not reach their original state. Electrode particles break apart, the electrode structure disintegrates, and the fragments loose contact to the rest of the cell.


Batteries x-rayed during operation


To better understand this complex electrochemical and mechanical degradation of the electrode and to gain insight into how to develop better batteries, Martin Ebner and ETH-Professor Vanessa Wood, head of the Laboratory for Nanoelectronics at D-ITET, recognized the need to study a battery electrode non-invasively during operation. To do so, they turned to an imaging tool developed by ETH-Professor Marco Stampanoni. Professsor Stampanoni, holds a faculty position at the Institute for Biomedical Engineering at D-ITET and runs the tomographic x-ray microscopy beamline at the Swiss Light Source, the synchrotron facility at the Paul Scherrer Institute. The spectrally pure and intense synchrotron x-ray radiation enables the fast acquisition of high-resolution x-ray images that can be computationally assembled into three-dimensional movies.


The researchers observed the inside of the battery as it charged and discharged over 15 hours. They gathered unique, three-dimensional movies that capture the degradation mechanisms occurring in the battery and quantified the processes occurring within every particle for the thousands of particles in the electrode. The results of this study will be published in the journal Science; a pre-print version is available online at Science Express.


Irreversible structural changes


The data illustrate that tin oxide (SnO) particles expand during charging due to the influx of lithium ions causing an increase in particle volume. The scientists demonstrate that material lithiation happens as a core-shell process, progressing uniformly from the particle surface to the core. The material undergoing this reaction expands linearly with the stored charge. The x-ray images show that charging destroys the particle structure irreversibly with cracks forming within the particles. "This crack-formation is not random," emphasizes Ebner. Cracks grow at locations where the crystal lattice contains preexisting defects. During discharge, the particle volume decreases; however, the material does not reach its original state again; the process is therefore not completely reversible.


The volume change of the individual particles drives expansion of the entire electrode from 50 micrometers to 120 micrometers. However, during discharge, the electrode contracts only to 80 micrometers. This permanent deformation of the electrode demonstrates that the polymer binder that holds the electrode together is not yet optimized for high volume expansion materials. This is critical for battery performance because deformation of the binder causes individual particles to become disconnected from the electrode and the battery looses capacity.


In addition to demonstrating that x-ray tomographic microscopy provides insight into morphological changes in the particles and electrodes, the researchers show that this technique can also be used to obtain quantitative and spatially resolved chemical information. For example, the researchers analyze chemical composition throughout the battery electrode to look at differences in lithiation dynamics at the single particle level and compare this to the average particle behavior. This approach is essential to understanding the influence of particle size, shape, and electrode homogeneity on battery performance.


Such insights into the operation of a battery would not be possible without the highly advanced x-ray tomography setup at the Swiss Light Source. "Visualizing batteries in operation was essentially impossible until recent advances in x-ray tomography. Thanks to the world class facilities developed by Professor Stampanoni and his team, we can watch the battery at work," adds Wood enthusiastically.


Alternatives to crystalline materials


The researchers chose crystalline tin oxide as a model material because it undergoes a series of complex transformations also present in other materials, enabling deeper understanding into the behavior of a variety of battery materials. The insights provide the basis for developing new electrode materials and electrode structures that are tolerant to volume expansion. For Prof. Wood the results of this work indicate the benefit of using amorphous or nanostructured materials instead of crystalline ones. "On the quest for new materials, one must also bear in mind that they are only of industrial interest if they can be produced in large quantities at a low cost. However, amorphous and nanostructured materials offer a sufficient playground for innovation." emphasizes Wood.


###


Reference


Ebner M, Marone F, Stampanoni M, Wood V. Visualization and quantification of electrochemical and mechanical degradation in Lithium ion batteries. Science Express, published online 17th October 2013.


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AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.




Source: http://www.eurekalert.org/pub_releases/2013-10/ez-wlf101713.php
Tags: Teyana Taylor   Boulder Flooding   Nokia   drake   Lisa Robin Kelly