Scientists at the Department of Energy’s Oak Ridge National Laboratory have discovered exceptional properties in a garnet material that could enable development of higher-energy battery designs.
The ORNL-led team used scanning transmission electron microscopy to take an atomic-level look at a cubic garnet material called LLZO. The researchers found the material to be highly stable in a range of aqueous environments, making the compound a promising component in new battery configurations.
Researchers frequently seek to improve a battery’s energy density by using a pure lithium anode, which offers the highest known theoretical capacity, and an aqueous electrolyte that can speedily transport lithium. The ORNL scientists believe the LLZO would be an ideal separator material, which is crucial.
“Many novel batteries adopt these two features [lithium anode and aqueous electrolyte], but if you integrate both into a single battery, a problem arises because the water is very reactive when in direct contact with lithium metal,” said ORNL postdoctoral associate Cheng Ma, first author on the team’s study published in Angewandte Chemie. “The reaction is very violent, which is why you need a protective layer around the lithium.”
Battery designers can use a solid electrolyte separator to shield the lithium, but their options are limited. Even the primary separator of choice, known as LAPT or LISICON, tends to break down under normal battery operating conditions.
“Researchers have searched for a suitable solid electrolyte separator material for years,” said ORNL’s Miaofang Chi, the study’s lead author. “The requirements for this type of material are very strict. It must be compatible with the lithium anode because lithium is reactive, and it also has to be stable over a wide pH range, because you can have an alkaline environment -- especially with lithium air batteries.”
The researchers used atomic resolution imaging to monitor structural changes in LLZO after the samples’ immersion in a range of aqueous solutions. The team’s observations showed that the compound remained structurally stable over time across neutral and extremely alkaline environments.
“This solid electrolyte separator remains stable even for a pH value higher than 14,” Ma said. “It gives battery designers more options for the selection of aqueous solutions and the catholyte.” Catholyte is the portion of the electrolyte close to the cathode.
In lithium-air batteries, for instance, researchers have previously tried to avoid the degradation of the separator by diluting the aqueous solutions, which only makes the battery heavier and bulkier. With this new type of solid electrolyte separator, there is no need to dilute the aqueous electrolyte, so it indirectly increases the battery’s energy density.
Higher-energy batteries are in demand for electrified transportation and electric grid energy storage applications, leading researchers to explore battery designs beyond the limits of lithium-ion technologies.
The researchers intend to continue their research by evaluating the LLZO garnet’s performance in an operating battery. Coauthors are ORNL’s Chengdu Liang, Karren More, Ezhiylmurugan Rangasamy, and Michigan State University’s Jeffrey Sakamoto. The study is published as “Excellent Stability of a Li-Ion-Conducting Solid Electrolyte upon Reversible Li+/H+ Exchange in Aqueous Solutions.”
This research was conducted in part at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility. The research was supported by DOE’s Office of Science.
UT-Battelle manages ORNL for the Department of Energy's Office of Science. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov/.
Morgan McCorkle | Eurek Alert!
Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz
Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Health and Medicine
18.10.2017 | Life Sciences
17.10.2017 | Life Sciences