Testing lithium battery limitations may improve safety and lifetimes

February 22, 2018 by Heidi Hill, Jeremy Rumsey, Oak Ridge National Laboratory
Researcher Rob Schmidt and his team are using neutrons at HFIR’s CG-1D imaging instrument to study the development of dendrites with hope of improving the design of next-generation lithium ion batteries. Dendrites are thin microscopic fibers that can carry electrical current inside lithium batteries and, in some cases, cause safety and reliability issues. Credit: ORNL/Genevieve Martin

Researchers are using neutrons to study a battery material that could offer a safer alternative to the flammable liquid component found in most types of lithium-ion batteries.

Rob Schmidt, a postdoctoral researcher at the Department of Energy's Oak Ridge National Laboratory, and his collaborators are using neutrons at the lab's High Flux Isotope Reactor (HFIR) to study a solid-core garnet material as a possible substitute for the flammable liquid cores often used in .

Batteries contain a core material known as an electrolyte that allows ions to travel between the positive and negative ends of the cell to maintain a balanced charge. However, most of the liquid eletrolytes used today in lithium-ion batteries are flammable. Schmidt is investigating a solid electrolyte material for potential use in the next generation of lithium-ion batteries for increased safety and reliability.

The team is using CG-1D's high sensitivity to lithium to track the lithium ion progression across the electrolyte and to observe the conditions that lead to the formation of unwanted dendrites. Dendrites, thin lithium metal filaments that can form inside battery cells, degrade battery performance by creating unwanted variations in electrical current distributions.

"Lithium is a soft metal material, so a lithium dendrite is able to go through liquids pretty easily, which makes it easy for batteries to short out," said Schmidt. "Lithium shouldn't go through a stiff, ceramic-like material like the garnet material we're studying, but it does. We want to know why and how it does that."

Schmidt hypothesized that the first step to failure is too much ion current in one area, followed by the formation of dendrites in areas that have greater lithium ion current density. The dendrite could create an easier path for ionic charges to move along than the . A partially formed dendrite concentrates ion current toward that easier pathway; once the fully forms between both electrodes, it creates an internal electrical short circuit.

"You really can't see dendrites well by probing with x-rays, but with neutrons, you can see where absorbs neutrons really, really well," he said.

If neutrons can help the team to better understand how dendrites form, they may be able to inform the design of new and ultimately safer batteries.

Explore further: Researchers design dendrite-free lithium battery

Related Stories

Researchers design dendrite-free lithium battery

January 8, 2018

By designing a solid electrolyte that is rigid on one side and soft on the other, researchers have fabricated a lithium-metal battery that completely suppresses dendrite formation—a major safety hazard that can cause fires ...

Taming 'dendrites' could bring better lithium-ion batteries

November 7, 2017

Researchers have learned the mechanisms behind a common type of failure in lithium-ion batteries caused by the formation and growth of "dendrites," findings that could aid in the design of faster-charging and longer-lasting ...

Graphene unlocks the promise of lithium sulfur batteries

December 18, 2017

Many battery scientists are interested in the potential of lithium sulfur batteries because, at least in theory, they offer a high energy density at relatively low cost. However, lithium sulfur batteries face a number of ...

Building better batteries

December 20, 2016

Lithium-ion batteries, widely used in devices ranging from electric cars to iPhones, are composed of a cathode made from a positively charged lithium compound and an anode composed of negatively charged carbon. Ideally, anodes ...

Recommended for you

Pushing lithium ion batteries to the next performance level

December 13, 2018

Conventional lithium ion batteries, such as those widely used in smartphones and notebooks, have reached performance limits. Materials chemist Freddy Kleitz from the Faculty of Chemistry of the University of Vienna and international ...

Uber filed paperwork for IPO: report

December 8, 2018

Ride-share company Uber quietly filed paperwork this week for its initial public offering, the Wall Street Journal reported late Friday.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.