Researchers tackle new challenge in pursuit of the next generation of lithium batteries

Sep 30, 2013 by Jared Sagoff
Lithium-air batteries are particularly appealing to researchers because they have a significantly higher theoretical capacity than conventional lithium-ion batteries.

The creation of the next generation of batteries depends on finding materials that provide greater storage capacity. One variety, known as lithium-air (Li-air) batteries, are particularly appealing to researchers because they have a significantly higher theoretical capacity than conventional lithium-ion batteries.

Li-air development is still in its infancy, however, and like most new technologies, it faces many challenges. One of these challenges involves the transfer of charge to the , which along with the cathode and electrolyte, is one of the three principal components of a battery.

In a new study, electrochemist Di-Jia (D.J.) Liu and his colleagues at the U.S. Department of Energy's Argonne National Laboratory studied anode behavior inside lithium-air batteries during the battery's cycling.

By using high-energy, focused X-ray beams provided by Argonne's Advanced Photon Source (APS), Liu and his team were able to non-destructively peer inside an operating battery to study the changes in the anode microstructure. They saw the formation of a thin solid coating of lithium hydroxide (LiOH), which continued to grow at the expense of lithium metal until the metal was totally converted to hydroxide and shut down the operation.

"This was the kind of question that everyone wanted to know but was afraid or didn't know how to ask," Liu said. "Nearly all the literature on Li-air batteries so far focused on the chemical processes at cathode while assuming the anode is completely reversible.  But now we know that this is not the case."

The team's investigation did not stop there. Since lithium hydroxide is not an ion or an electron-conducting material, it remained a mystery to understand how the coating does not stop the battery from cycling as soon as it forms.  Using a 3-dimensional micro-tomography technique at the APS, Liu and his collaborators were able to perform a "CAT scan" of the hydroxide coating and found numerous microscopic tunnels connecting to the metallic lithium at the anode to the rest of the battery.   

"These tunnels serve as ion-conducting channels that shuttle lithium ions between the anode and cathode," Liu said. "They sustained the Li-air battery operation but did not stop the anode decay."

Liu believes that one major cause of the lithium hydroxide problem could involve the breakdown of the battery's electrolyte – the medium that transports lithium ions between the two electrodes. Decomposition of the electrolyte has the potential to form water near the cathode, which could then migrate to the anode and react with the metallic lithium.

However, the Argonne experiment didn't reveal any lithium hydroxide near the cathode, which should have been present if water were formed by the breakdown of the electrolyte. "I think that we generated as many questions as answers through this study, which is the exciting part of science," he said.

This work was performed by an all Argonne team including beamline scientists John Okasinski, Peter Kenesei, Jonathan Almer and chemistry postdocs Jianglan Shui and Dan Zhao. It was supported by the U.S. Department of Energy's Office of Science and Argonne's Grand Challenge Program. The work was published in the August 9 issue of Nature Communications.

Explore further: Designer glue improves lithium-ion battery life

Related Stories

Designer glue improves lithium-ion battery life

Aug 20, 2013

(Phys.org) —When it comes to improving the performance of lithium-ion batteries, no part should be overlooked – not even the glue that binds materials together in the cathode, researchers at SLAC and ...

Solid-state battery could double the range of electric cars

Sep 19, 2013

(Phys.org) —A cutting-edge battery technology developed at the University of Colorado Boulder that could allow tomorrow's electric vehicles to travel twice as far on a charge is now closer to becoming a commercial reality.

Fluoride shuttle increases storage capacity

Oct 21, 2011

German researchers have developed a new concept for rechargeable batteries. Based on a fluoride shuttle -- the transfer of fluoride anions between the electrodes -- it promises to enhance the storage capacity ...

Eavesdropping on lithium ions

Jul 08, 2013

(Phys.org) —Lithium ion batteries are at the energetic heart of almost all things tech, from cell phones to tablets to electric vehicles. That's because they are a proven technology, light, long-lasting ...

Recommended for you

Obama launches measures to support solar energy in US

22 hours ago

The White House Thursday announced a series of measures aimed at increasing solar energy production in the United States, particularly by encouraging the installation of solar panels in public spaces.

Tailored approach key to cookstove uptake

22 hours ago

Worldwide, programs aiming to give safe, efficient cooking stoves to people in developing countries haven't had complete success—and local research has looked into why.

Wireless power transfer achieved at five-meter distance

22 hours ago

The way electronic devices receive their power has changed tremendously over the past few decades, from wired to non-wired. Users today enjoy all kinds of wireless electronic gadgets including cell phones, ...

User comments : 0

More news stories

LADEE mission ends with planned lunar impact

(Phys.org) —Ground controllers at NASA's Ames Research Center in Moffett Field, Calif., have confirmed that NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft impacted the surface ...