Featured Research

from universities, journals, and other organizations

Antimony nanocrystals for batteries

Date:
March 18, 2014
Source:
ETH Zürich
Summary:
Researchers have succeeded for the first time to produce uniform antimony nanocrystals. Tested as components of laboratory batteries, these are able to store a large number of both lithium and sodium ions. These nanomaterials operate with high rate and may eventually be used as alternative anode materials in future high-energy-density batteries.

TEM image (false coloured) of monodisperse antimony nanocrystals.
Credit: Maksym Kovalenko Group / ETH Zurich

Researchers from ETH Zurich and Empa have succeeded for the first time to produce uniform antimony nanocrystals. Tested as components of laboratory batteries, these are able to store a large number of both lithium and sodium ions. These nanomaterials operate with high rate and may eventually be used as alternative anode materials in future high-energy-density batteries.

The hunt is on -- for new materials to be used in the next generation of batteries that may one day replace current lithium ion batteries. Today, the latter are commonplace and provide a reliable power source for smartphones, laptops and many other portable electrical devices.

On the one hand, however, electric mobility and stationary electricity storage demand a greater number of more powerful batteries; and the high demand for lithium may eventually lead to a shortage of the raw material. This is why conceptually identical technology based on sodium-ions will receive increasing attention in coming years. Contrary to lithium batteries, researched for more than 20 years, much less is known about materials that can efficiently store sodium ions.

Antimony electrodes?

A team of researchers from ETH Zurich and Empa headed by Maksym Kovalenko may have come a step closer to identifying alternative battery materials: they have become the first to synthesise uniform antimony nanocrystals, the special properties of which make them prime candidates for an anode material for both lithium-ion and sodium-ion batteries. The results of the scientists' study have just been published in Nano Letters.

For a long time, antimony has been regarded as a promising anode material for high-performance lithium-ion batteries as this metalloid exhibits a high charging capacity, by a factor of two higher than that of commonly used graphite. Initial studies revealed that antimony could be suitable for rechargeable lithium and sodium ion batteries because it is able to store both kinds of ions. Sodium is regarded as a possible low-cost alternative to lithium as it is much more naturally abundant and its reserves are more evenly distributed on Earth.

For antimony to achieve its high storage capability, however, it needs to be produced in a special form. The researchers managed to chemically synthesize uniform -- so-called "monodisperse" -- antimony nanocrystals that were between ten and twenty nanometres in size.

The full lithiation or sodiation of antimony leads to large volumetric changes. By using nanocrystals, these modulations of the volume can be reversible and fast, and do not lead to the immediate fracture of the material. An additional important advantage of nanocrystals (or nanoparticles) is that they can be intermixed with a conductive carbon filler in order to prevent the aggregation of the nanoparticles.

Ideal candidate for anode material

Electrochemical tests showed Kovalenko and his team that electrodes made of these antimony nanocrystals perform equally well in sodium and in lithium ion batteries. This makes antimony particularly promising for sodium batteries because the best lithium-storing anode materials (Graphite and Silicon) do not operate with sodium.

Highly monodisperse nanocrystals, with the size deviation of ten percent or less, allow identifying the optimal size-performance relationship. Nanocrystals of ten nanometers or smaller suffer from oxidation because of the excessive surface area. On the other hand, antimony crystals with a diameter of more than 100 nanometres aren't sufficiently stable due to aforementioned massive volume expansion and contraction during the operation of a battery. The researchers achieved the best results with 20 nanometer large particles.

Performance not so size dependent

Another important outcome of this study, enabled by these ultra-uniform particles, is that the researchers identified a size-range of around 20 to 100 nanometres within which this material shows excellent, size-independent performance, both in terms of energy density and rate-capability.

These features even allow using polydisperse antimony particles to obtain the same performance as with very monodisperse particles, as long as their sizes remain within this size-range of 20 to 100 nanometres.

"This greatly simplifies the task of finding an economically viable synthesis method," Kovalenko says. "Development of such cost-effective synthesis is the next step for us, together with our industrial partner." Experiments of his group on monodisperse nanoparticles of other materials show much steeper size-performance relationships such as quick performance decay with increasing the particle size, placing antimony into a unique position among the materials which alloy with lithium and sodium.

More expensive alternative

Does this mean that an alternative to today's lithium-ion batteries is within our grasp? Kovalenko shakes his head. Although the method is relatively straightforward, the production of a sufficient number of high-quality uniform antimony nanocrystals is still too expensive.

"All in all, batteries with sodium-ions and antimony nanocrystals as anodes will only constitute a highly promising alternative to today's lithium-ion batteries if the costs of producing the batteries will be comparable," says Kovalenko.

It will be another decade or so before a sodium-ion battery with antimony electrodes could hit the market, the ETH-Zurich professor estimates. The research on the topic is still only in its infancy. "However, other research groups will soon join the efforts," the chemist is convinced.


Story Source:

The above story is based on materials provided by ETH Zürich. Note: Materials may be edited for content and length.


Journal Reference:

  1. Meng He, Kostiantyn Kravchyk, Marc Walter, Maksym V. Kovalenko. Monodisperse Antimony Nanocrystals for High-Rate Li-ion and Na-ion Battery Anodes: Nano versus Bulk. Nano Letters, 2014; 14 (3): 1255 DOI: 10.1021/nl404165c

Cite This Page:

ETH Zürich. "Antimony nanocrystals for batteries." ScienceDaily. ScienceDaily, 18 March 2014. <www.sciencedaily.com/releases/2014/03/140318093226.htm>.
ETH Zürich. (2014, March 18). Antimony nanocrystals for batteries. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2014/03/140318093226.htm
ETH Zürich. "Antimony nanocrystals for batteries." ScienceDaily. www.sciencedaily.com/releases/2014/03/140318093226.htm (accessed August 21, 2014).

Share This




More Matter & Energy News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Flower Power! Dandelions Make Car Tires?

Flower Power! Dandelions Make Car Tires?

Reuters - Business Video Online (Aug. 20, 2014) — Forget rolling on rubber, could car drivers soon be traveling on tires made from dandelions? Teams of scientists are racing to breed a type of the yellow flower whose taproot has a milky fluid with tire-grade rubber particles in it. As Joanna Partridge reports, global tire makers are investing millions in research into a new tire source. Video provided by Reuters
Powered by NewsLook.com
Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) — Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Researcher Testing on-Field Concussion Scanners

Researcher Testing on-Field Concussion Scanners

AP (Aug. 19, 2014) — Four Texas high school football programs are trying out an experimental system designed to diagnose concussions on the field. The technology is in response to growing concern over head trauma in America's most watched sport. (Aug. 19) Video provided by AP
Powered by NewsLook.com
Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

Green Power Blooms as Japan Unveils 'hydrangea Solar Cell'

AFP (Aug. 19, 2014) — A solar cell that resembles a flower is offering a new take on green energy in Japan, where one scientist is searching for renewables that look good. Duration: 01:29 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins