Subscribe free to our newsletters via your
  Energy News  




Subscribe free to our newsletters via your




















ENERGY TECH
Toward all-solid lithium batteries
by Staff Writers
Boston MA (SPX) Feb 03, 2017


Using specialized equipment, the MIT team did tests in which they used a pyramidal-tipped probe to indent the surface of a piece of the sulfide-based material. Surrounding the resulting indentation (seen at center), cracks were seen forming in the material (indicated by arrows), revealing details of its mechanical properties. Image courtesy of the researchers.

Most batteries are composed of two solid, electrochemically active layers called electrodes, separated by a polymer membrane infused with a liquid or gel electrolyte. But recent research has explored the possibility of all-solid-state batteries, in which the liquid (and potentially flammable) electrolyte would be replaced by a solid electrolyte, which could enhance the batteries' energy density and safety.

Now, for the first time, a team at MIT has probed the mechanical properties of a sulfide-based solid electrolyte material, to determine its mechanical performance when incorporated into batteries.

The new findings were published this week in the journal Advanced Energy Materials, in a paper by Frank McGrogan and Tushar Swamy, both MIT graduate students; Krystyn Van Vliet, the Michael (1949) and Sonja Koerner Professor of Materials Science and Engineering; Yet-Ming Chiang, a professor of materials science and engineering; and four others including an undergraduate participant in the National Science Foundation Research Experience for Undergraduate (REU) program administered by MIT's Center for Materials Science and Engineering and its Materials Processing Center.

Lithium-ion batteries have provided a lightweight energy-storage solution that has enabled many of today's high-tech devices, from smartphones to electric cars. But substituting the conventional liquid electrolyte with a solid electrolyte in such batteries could have significant advantages.

Such all-solid-state lithium-ion batteries could provide even greater energy storage ability, pound for pound, at the battery pack level. They may also virtually eliminate the risk of tiny, fingerlike metallic projections called dendrites that can grow through the electrolyte layer and lead to short-circuits.

"Batteries with components that are all solid are attractive options for performance and safety, but several challenges remain," Van Vliet says.

In the lithium-ion batteries that dominate the market today, lithium ions pass through a liquid electrolyte to get from one electrode to the other while the battery is being charged, and then flow through in the opposite direction as it is being used. These batteries are very efficient, but "the liquid electrolytes tend to be chemically unstable, and can even be flammable," she says. "So if the electrolyte was solid, it could be safer, as well as smaller and lighter."

But the big question regarding the use of such all-solid batteries is what kinds of mechanical stresses might occur within the electrolyte material as the electrodes charge and discharge repeatedly. This cycling causes the electrodes to swell and contract as the lithium ions pass in and out of their crystal structure.

In a stiff electrolyte, those dimensional changes can lead to high stresses. If the electrolyte is also brittle, that constant changing of dimensions can lead to cracks that rapidly degrade battery performance, and could even provide channels for damaging dendrites to form, as they do in liquid-electrolyte batteries. But if the material is resistant to fracture, those stresses could be accommodated without rapid cracking.

Until now, though, the sulfide's extreme sensitivity to normal lab air has posed a challenge to measuring mechanical properties including its fracture toughness. To circumvent this problem, members of the research team conducted the mechanical testing in a bath of mineral oil, protecting the sample from any chemical interactions with air or moisture.

Using that technique, they were able to obtain detailed measurements of the mechanical properties of the lithium-conducting sulfide, which is considered a promising candidate for electrolytes in all-solid-state batteries.

"There are a lot of different candidates for solid electrolytes out there," McGrogan says. Other groups have studied the mechanical properties of lithium-ion conducting oxides, but there had been little work so far on sulfides, even though those are especially promising because of their ability to conduct lithium ions easily and quickly.

Previous researchers used acoustic measurement techniques, passing sound waves through the material to probe its mechanical behavior, but that method does not quantify the resistance to fracture. But the new study, which used a fine-tipped probe to poke into the material and monitor its responses, gives a more complete picture of the important properties, including hardness, fracture toughness, and Young's modulus (a measure of a material's capacity to stretch reversibly under an applied stress).

"Research groups have measured the elastic properties of the sulfide-based solid electrolytes, but not fracture properties," Van Vliet says. The latter are crucial for predicting whether the material might crack or shatter when used in a battery application.

The researchers found that the material has a combination of properties somewhat similar to silly putty or salt water taffy: When subjected to stress, it can deform easily, but at sufficiently high stress it can crack like a brittle piece of glass.

By knowing those properties in detail, "you can calculate how much stress the material can tolerate before it fractures," and design battery systems with that information in mind, Van Vliet says.

The material turns out to be more brittle than would be ideal for battery use, but as long as its properties are known and systems designed accordingly, it could still have potential for such uses, McGrogan says. "You have to design around that knowledge."

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Massachusetts Institute of Technology
Powering The World in the 21st Century at Energy-Daily.com






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
ENERGY TECH
GM, Honda annouce fuel cell venture in Michigan
New York (AFP) Jan 30, 2017
General Motors and Honda announced plans Monday for the first "mass production" of an advanced hydrogen fuel cell system that could be used in future vehicles. The two companies, which have collaborated on the technology since 2013, will launch the Fuel Cell System Manufacturing venture in an existing GM battery facility in Brownstown, Michigan, south of Detroit, the US auto capital. Pro ... read more


ENERGY TECH
Nordic countries are bringing about an energy transition worth copying

Iraq inks billion-dollar power plant deal with GE

China energy firm expands in crisis-hit Brazil

Europe to take up climate investment mantle

ENERGY TECH
GM, Honda annouce fuel cell venture in Michigan

Researchers flip script for Li-Ion electrolytes to simulate better batteries

Scientists take the first step toward creating efficient electrolyte-free batteries

Former OPEC member Indonesia makes geothermal move

ENERGY TECH
Prysmian UK to supply land cable connections for East Anglia ONE offshore wind farm

Russia's nuclear giant pushes into wind energy

The power of wind energy and how to use it

Largest US offshore wind farm gets green light

ENERGY TECH
Eltek to provide solar energy for hospitals in Zimbabwe under UNDP programme

Saudi Arabia takes low-carbon energy approach

NRDC: States should lead low-carbon economy

Storing solar power increases energy consumption and emissions

ENERGY TECH
Toshiba to stop building new nuclear plants: report

International partnerships vital for UK nuclear energy

Canada uranium supplier, Fukushima operator in contract fight

Russia 'ready' to entirely fund Hungary nuclear plant

ENERGY TECH
DuPont Industrial Biosciences to develop new high-efficiency biogas enzyme method

Cathay Pacific to cut emissions with switch to biofuel

Populus dataset holds promise for biofuels, materials, metabolites

Handheld Sensor Unit Determines Biofuel Content Of Diesel Blends

ENERGY TECH
Russia could move quicker on oil production declines

Early rally in oil fizzles on Libyan rebound

Average U.S. gas prices decline for 21 consecutive days

Kuwaitis seek roots in upmarket tents under the stars

ENERGY TECH
The ancient Indus civilization's adaptation to climate change

Florida corals tell of cold spells and dust bowls past, foretell weather to come

Study reveals that climate change could dramatically alter fragile mountain habitats

Climate change to shift global pattern of mild weather




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement