Featured Research

from universities, journals, and other organizations

'Wetting' a battery's appetite for renewable energy storage: New liquid alloy electrode improves sodium-beta battery performance

Date:
August 1, 2014
Source:
Pacific Northwest National Laboratory
Summary:
A new liquid metal alloy enables sodium-beta batteries to operate at lower temperatures, which could help the batteries store more renewable energy and strengthen the power grid.

The traditional design of sodium-beta batteries, which uses pure molten sodium for a negative electrode, can be inefficient, as the sodium tends to ball up on the surface of the battery’s ceramic electrolyte, as shown on the left. PNNL researchers developed a new negative electrode made of a sodium-cesium alloy that almost completely coats, or “wets,” the electrolyte surface, as shown on the right.
Credit: Image courtesy of Pacific Northwest National Laboratory

Sun, wind and other renewable energy sources could make up a larger portion of the electricity America consumes if better batteries could be built to store the intermittent energy for cloudy, windless days. Now a new material could allow more utilities to store large amounts of renewable energy and make the nation's power system more reliable and resilient.

A paper published today in Nature Communications describes an electrode made of a liquid metal alloy that enables sodium-beta batteries to operate at significantly lower temperatures. The new electrode enables sodium-beta batteries to last longer, helps streamline their manufacturing process and reduces the risk of accidental fire.

"Running at lower temperatures can make a big difference for sodium-beta batteries and may enable batteries to store more renewable energy and strengthen the power grid," said material scientist Xiaochuan Lu of the Department of Energy's Pacific Northwest National Laboratory.

Need for energy storage, but challenges remain

More than 300 megawatts of large, cargo container-sized sodium-beta batteries are running in the United States, Japan and Europe, according to Dupont Energy Consulting. They often store electricity generated by rows of solar panels and wind turbines.

But their broader use has been limited because of their high operating temperature, which reaches up to 350 degrees Celsius, or more than three times the boiling point of water. Such high operating temperatures requires sodium-beta batteries to use more expensive materials and shortens their operating lifespans. PNNL researchers set out to reduce the battery's operating temperature, knowing that could make the battery more efficient and last longer.

The traditional design of sodium-beta batteries consists of two electrodes separated by a solid membrane made of the ceramic material beta alumina. There are two main types of sodium-beta batteries, based on the materials used for the positive electrode: those that use sulfur are called sodium-sulfur batteries, while those that use nickel chloride are known as ZEBRA batteries. Electricity is generated when electrons flow between the battery's electrodes.

Lowering the battery's operating temperature creates several other technical challenges. Key among them is getting the negative sodium electrode to fully coat, or "wet" the ceramic electrolyte. Molten sodium resists covering beta alumina's surface when it's below 400 degrees Celsius, causing sodium to curl up like a drop of oil in water, making the battery less efficient. For decades researchers have tried to overcome this by applying different coatings to the membrane.

New electrode offers different take

Lu and his PNNL colleagues took an entirely different approach to the wettability problem: modifying the negative electrode. Instead of using pure sodium, they experimented with sodium alloys, or sodium blended with other metals. The team determined a liquid sodium-cesium alloy spreads out well on the beta alumina membrane.

PNNL's new electrode material enables the battery to operate at lower temperatures. Instead of the 350 degrees Celsius at which traditional sodium-beta batteries operate, a test battery with the new electrode worked well at 150 degrees -- with a power capacity of 420 milliampere-hours per gram, matching the capacity of the traditional design.

Batteries with the new alloy electrode also retain more of their original energy storage capacity. After 100 charge and discharge cycles, a test battery with PNNL's electrode maintained about 97 percent of its initial storage capacity, while a battery with the traditional, sodium-only electrode maintained 70 percent after 60 cycles.

A battery with a lower operating temperature can also use less expensive materials such as polymers -- which would melt at 350 degrees Celsius -- for its external casing instead of steel. Using less expensive and sensitive materials would also help streamline the battery's manufacturing process. This offsets some of the increased cost associated with using cesium, which is more expensive than sodium.

The PNNL research team is now building a larger electrode to test with a larger battery to bring the technology closer to the scale needed to store renewable energy.

This research was supported by DOE's Office of Electricity Delivery and Energy Reliability and internal PNNL funding.


Story Source:

The above story is based on materials provided by Pacific Northwest National Laboratory. The original article was written by Frances White. Note: Materials may be edited for content and length.


Journal Reference:

  1. Xiaochuan Lu, Guosheng Li, Jin Y. Kim, Donghai Mei, John P. Lemmon, Vincent L. Sprenkle, Jun Liu. Liquid-metal electrode to enable ultra-low temperature sodium–beta alumina batteries for renewable energy storage. Nature Communications, 2014; 5 DOI: 10.1038/ncomms5578

Cite This Page:

Pacific Northwest National Laboratory. "'Wetting' a battery's appetite for renewable energy storage: New liquid alloy electrode improves sodium-beta battery performance." ScienceDaily. ScienceDaily, 1 August 2014. <www.sciencedaily.com/releases/2014/08/140801104242.htm>.
Pacific Northwest National Laboratory. (2014, August 1). 'Wetting' a battery's appetite for renewable energy storage: New liquid alloy electrode improves sodium-beta battery performance. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2014/08/140801104242.htm
Pacific Northwest National Laboratory. "'Wetting' a battery's appetite for renewable energy storage: New liquid alloy electrode improves sodium-beta battery performance." ScienceDaily. www.sciencedaily.com/releases/2014/08/140801104242.htm (accessed October 21, 2014).

Share This



More Matter & Energy News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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