Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Charging makes nano-sized electrodes swell, elongate and spiral

This nano-sized battery reveals how positive lithium ions flood the negative electrode (blue), changing the size, shape and nature of the material (the green part of the electrode). Some rechargeable materials might be more resilient than others to the repeated shape-changing. Credit Pacific Northwest National Laboratory
This nano-sized battery reveals how positive lithium ions flood the negative electrode (blue), changing the size, shape and nature of the material (the green part of the electrode). Some rechargeable materials might be more resilient than others to the repeated shape-changing. Credit Pacific Northwest National Laboratory

Abstract:
High-resolution video shows how batteries wear out over time

Charging makes nano-sized electrodes swell, elongate and spiral

Richland, WA | Posted on December 14th, 2010

New high resolution images of electrode wires made from materials used in rechargeable lithium ion batteries shows them contorting as they become charged with electricity. The thin, nano-sized wires writhe and fatten as lithium ions flow in during charging, according to a paper in this week's issue of the journal Science. The work suggests how rechargeable batteries eventually give out and might offer insights for building better batteries.

Battery developers know that recharging and using lithium batteries over and over damages the electrode materials, but these images at nanometer scale offer a real-life glimpse into how. Thin wires of tin oxide, which serve as the negative electrode, fatten by a third and stretch twice as long due to lithium ions coursing in. In addition, the lithium ions change the tin oxide from a neatly arranged crystal to an amorphous glassy material.

"Nanowires of tin oxide were able to withstand the deformations associated with electrical flow better than bulk tin oxide, which is a brittle ceramic," said Chongmin Wang, a materials scientist at the Department of Energy's Pacific Northwest National Laboratory. "It reminds me of making a rope from steel — you wind together thinner wires rather than making one thick rope."

In one of the videos (*) the nanowire appears like a straw, while the lithium ions seem like a beverage being sucked up through it. Repeated shape changes could damage the electrode materials by introducing tiny defects that accumulate over time.

Chasing Electrons

In previous work at DOE's Environmental Molecular Sciences Laboratory on the PNNL campus, Wang, PNNL chemist Wu Xu and other colleagues succeeded in taking a snapshot of a larger nanowire of about one micrometer — or one-hundredth the width of a human hair — that had been partially charged. But the experimental set-up didn't show charging in action.

To view the dynamics of an electrode being charged, Wang and Xu teamed up with Jianyu Huang at DOE's Center for Integrated Nanotechnologies at Sandia National Laboratories in New Mexico and others. The team used a specially outfitted transmission electron microscope to set up a miniature battery. This instrument allowed them to image smaller wires of about 200 nanometers in diameter (about a fifth the width of the previous nanowires) while charging it.

Rechargeable lithium ion batteries work because lithium ions love electrons. Positively charged lithium ions normally hang out in the positive electrode, where a metal oxide shares its electrons with lithium. But charging a battery pumps free electrons into the negative electrode, which sits across a lake of electrolytes through which lithium ions can swim but electrons can't. The lithium desires the electrons on the negative side of the lake more than the electrons it shares with the metal oxide on the positive side. So lithium ions flow from the positive to the negative electrode, pairing up with free electrons there.

But electrons are fickle. Using a battery in a device allows the electrons to slip out of the negative electrode, leaving the lithium ions behind. So without free electron companions, the lithium ions return to the positive electrode and the metal oxide's embrace.

Wang's miniature battery included a positive electrode of lithium cobalt oxide and a negative electrode made from thin nanowires of tin oxide. Between the two electrodes, an electrolyte provided a conduit for lithium ions and a barrier for electrons. The electrolyte was specially designed to withstand the conditions in the microscope.

When the team charged the miniature battery at a constant voltage, lithium ions wicked up through the tin oxide wire, drawn by the electrons at the negative electrode. The wire fattened and lengthened by about 250 percent in total volume, and twisted like a snake.

In addition, the microscopy showed that the wire started out in a crystalline form. But the lithium ions changed the tin oxide to a glassy material, in which atoms are arranged more randomly than in a crystal. The researchers concluded the amount of deformation occurring during charging and use might wear down battery materials after a while. Even so, the tin oxide appeared to fare better as a nanowire than in its larger, bulk form.

"We think this work will stimulate new thinking for energy storage in general," said Wang. "This is just the beginning, and we hope with continued work it will show us how to design a better battery."

Future work will include imaging what happens when such a miniature battery is repeatedly charged and discharged. When a battery gets used, the lithium ions must run back through the tin oxide wire and across the electrolyte to the positive electrode. How much structural damage the receding lithium leaves in its wake will help researchers understand why rechargeable batteries stop working after being recharged so many times.

The researchers would also like to develop a fully functioning nano-sized rechargeable battery.

Reference: Jian Yu Huang, Li Zhong, Chong Min Wang, John P. Sullivan, Wu Xu, Li Qiang Zhang, Scott X. Mao, Nicholas S. Hudak, Xiao Hua Liu, Arunkumar Subramanian, Hong You Fan, Liang Qi, Akihiro Kushima, Ju Li, In situ observation of the electrochemical lithiation of a single SnO2 nanowire electrode, Dec. 10, 2010, Science, DOI 10.1126/science.1195628.

This work was supported by EMSL and the Department of Energy Office of Science.

(*) mt.seas.upenn.edu/Stuff/JianyuHuang/Upload/S1.mov

####

About Pacific Northwest National Laboratory
Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, the environment and national security. PNNL employs 4,900 staff, has an annual budget of nearly $1.1 billion, and has been managed by Ohio-based Battelle since the lab's inception in 1965.

For more information, please click here

Contacts:
Mary Beckman
PNNL
(509) 375-3688

Copyright © Pacific Northwest National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

NANOPOSTER 2015 - 5th Virtual Nanotechnology Conference - call for abstracts January 24th, 2015

Nanosensor Used for Simultaneous Determination of Effective Tea Components January 24th, 2015

Chemistry

Anti-microbial coatings with a long-term effect for surfaces – presentation at nano tech 2015 in Japan January 21st, 2015

Hydrogels deliver on blood-vessel growth: Rice researchers introduce improved injectable scaffold to promote healing January 20th, 2015

Graphene enables all-electrical control of energy flow from light emitters: First signatures of graphene plasmons at telecommunications wavelength revealed January 20th, 2015

Nanotechnology Used to Produce Ceramic Membrane with High Thermal Stability January 19th, 2015

Govt.-Legislation/Regulation/Funding/Policy

The latest fashion: Graphene edges can be tailor-made: Rice University theory shows it should be possible to tune material's properties January 24th, 2015

Scientists 'bend' elastic waves with new metamaterials that could have commercial applications: Materials could benefit imaging and military enhancements such as elastic cloaking January 23rd, 2015

Harper Government Supports Research Innovation in Western Canada January 22nd, 2015

EnvisioNano: An image contest hosted by the National Nanotechnology Initiative (NNI) January 22nd, 2015

Possible Futures

GS7 Graphene Sensor maybe Solution in Fight Against Cancer January 25th, 2015

Nanotechnology in Energy Applications Market Research Report 2014-2018: Radiant Insights, Inc January 15th, 2015

'Mind the gap' between atomically thin materials December 23rd, 2014

A novel method for identifying the body’s ‘noisiest’ networks November 19th, 2014

Appointments/Promotions/New hires/Resignations/Deaths

Rice's Naomi Halas to direct Smalley Institute: Optics pioneer will lead Rice's multidisciplinary science institute January 15th, 2015

SUNY Board Appoints Dr. Alain Kaloyeros as Founding President of SUNY Polytechnic Institute January 13th, 2015

Blend Therapeutics Appoints Distinguished Physician Scientist, Dennis Ausiello, MD, to Board of Directors January 8th, 2015

QD Vision Receives New Funding Round to Meet Growing Demand for Quantum Dot Technology: Industry Veteran Steve Ward Named Executive Chairman January 5th, 2015

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

Smart keyboard cleans and powers itself -- and can tell who you are January 21st, 2015

Presence of Nanoparticles in Efforts to Boost Lifetime of Super Capacitors January 20th, 2015

Carbon nanotube finding could lead to flexible electronics with longer battery life January 14th, 2015

Research partnerships

Wearable sensor clears path to long-term EKG, EMG monitoring January 20th, 2015

Graphene enables all-electrical control of energy flow from light emitters: First signatures of graphene plasmons at telecommunications wavelength revealed January 20th, 2015

Charge instability detected across all types of copper-based superconductors: Findings may help researchers synthesize materials that can superconduct at room temperature January 16th, 2015

Gold nanoparticles show promise for early detection of heart attacks: NYU School of Engineering Professors collaborate with researchers from Peking University on a new test strip January 15th, 2015

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE