Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

World’s smallest battery created at CINT nanotechnology center

10.12.2010
Snake-like “Medusa front” offers “a view never before seen” to improve lithium batteries

A benchtop version of the world’s smallest battery — its anode a single nanowire one seven-thousandth the thickness of a human hair —has been created by a team led by Sandia National Laboratories researcher Jianyu Huang.

To better study the anode’s characteristics, the tiny rechargeable, lithium-based battery was formed inside a transmission electron microscope (TEM) at the Center for Integrated Nanotechnologies (CINT), a Department of Energy research facility jointly operated by Sandia and Los Alamos national laboratories.

Says Huang of the work, reported in the Dec. 10 issue of the journal Science, “This experiment enables us to study the charging and discharging of a battery in real time and at atomic scale resolution, thus enlarging our understanding of the fundamental mechanisms by which batteries work.”

Because nanowire-based materials in lithium ion batteries offer the potential for significant improvements in power and energy density over bulk electrodes, more stringent investigations of their operating properties should improve new generations of plug-in hybrid electric vehicles, laptops and cell phones.

“What motivated our work,” says Huang, “is that lithium ion batteries [LIB] have very important applications, but the low energy and power densities of current LIBs cannot meet the demand. To improve performance, we wanted to understand LIBs from the bottom up, and we thought in-situ TEM could bring new insights to the problem.”

Battery research groups do use nanomaterials as anodes, but in bulk rather than individually — a process, Huang says, that resembles “looking at a forest and trying to understand the behavior of an individual tree.”

The tiny battery created by Huang and co-workers consists of a single tin oxide nanowire anode 100 nanometers in diameter and 10 micrometers long, a bulk lithium cobalt oxide cathode three millimeters long, and an ionic liquid electrolyte. The device offers the ability to directly observe change in atomic structure during charging and discharging of the individual “trees.”

An unexpected find of the researchers was that the tin oxide nanowire rod nearly doubles in length during charging — far more than its diameter increases — a fact that could help avoid short circuits that may shorten battery life. “Manufacturers should take account of this elongation in their battery design,” Huang said. (The common belief of workers in the field has been that batteries swell across their diameter, not longitudinally.)

Huang’s group found this flaw by following the progression of the lithium ions as they travel along the nanowire and create what researchers christened the “Medusa front” — an area where high density of mobile dislocations cause the nanowire to bend and wiggle as the front progresses. The web of dislocations is caused by lithium penetration of the crystalline lattice. “These observations prove that nanowires can sustain large stress (>10 GPa) induced by lithiation without breaking, indicating that nanowires are very good candidates for battery electrodes,” said Huang.

“Our observations — which initially surprised us — tell battery researchers how these dislocations are generated, how they evolve during charging, and offer guidance in how to mitigate them,” Huang said. “This is the closest view to what’s happening during charging of a battery that researcher have achieved so far.”

Lithiation-induced volume expansion, plasticity and pulverization of electrode materials are the major mechanical defects that plague the performance and lifetime of high-capacity anodes in lithium-ion batteries, Huang said. “So our observations of structural kinetics and amorphization [the change from normal crystalline structure] have important implications for high-energy battery design and in mitigating battery failure.”

The electronic noise level generated from the researchers’ measurement system was too high to read electrical currents, but Sandia co-author John Sullivan estimated a current level of a picoampere flowing in the nanowire during charging and discharging. The nanowire was charged to a potential of about 3.5 volts, Huang said.

A picoampere is a millionth of a microampere. A microampere is a millionth of an ampere.

The reason that atomic-scale examination of the charging and discharging process of a single nanowire had not been possible was because the high vacuum in a TEM made it difficult to use a liquid electrolyte. Part of the Huang group’s achievement was to demonstrate that a low-vapor-pressure ionic liquid — essentially, molten salt —could function in the vacuum environment.

Although the work was carried out using tin oxide (SnO2) nanowires, the experiments can be extended to other materials systems, either for cathode or anode studies, Huang said.

“The methodology that we developed should stimulate extensive real-time studies of the microscopic processes in batteries and lead to a more complete understanding of the mechanisms governing battery performance and reliability,” he said. “Our experiments also lay a foundation for in-situ studies of electrochemical reactions, and will have broad impact in energy storage, corrosion, electrodeposition and general chemical synthesis research field.”

Other researchers contributing to this work include Xiao Hua Liu, Nicholas Hudak, Arunkumar Subramanian and Hong You Fan, all of Sandia; Li Zhong, Scott Mao and Li Qiang Zhang of the University of Pittsburgh; Chong Min Wang and Wu Xu of Pacific Northwest National Laboratory; and Liang Qi, Akihiro Kushima and Ju Li of the University of Pennsylvania.

Funding came from Sandia’s Laboratory Directed Research and Development Office and the Department of Energy’s Office of Science through the Center for Integrated Nanotechnologies and the Energy Frontier Research Centers program.

Sandia National Laboratories is a multiprogram laboratory operated and managed by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.

Sandia news media contact: Neal Singer, nsinger@sandia.gov (505) 845-7078

Neal Singer | EurekAlert!
Further information:
http://www.sandia.gov

More articles from Power and Electrical Engineering:

nachricht Waste from paper and pulp industry supplies raw material for development of new redox flow batteries
12.10.2017 | Johannes Gutenberg-Universität Mainz

nachricht Low-cost battery from waste graphite
11.10.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Neutron star merger directly observed for the first time

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...

Im Focus: Breaking: the first light from two neutron stars merging

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....

Im Focus: Smart sensors for efficient processes

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...

Im Focus: Cold molecules on collision course

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...

Im Focus: Shrinking the proton again!

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Terahertz spectroscopy goes nano

20.10.2017 | Information Technology

Strange but true: Turning a material upside down can sometimes make it softer

20.10.2017 | Materials Sciences

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>