Featured Research

from universities, journals, and other organizations

Toughened silicon sponges may make tenacious batteries

Date:
July 16, 2012
Source:
Rice University
Summary:
Researchers have found a way to make multiple high-performance anodes from a single silicon wafer. The process uses simple silicon to replace graphite as an element in rechargeable lithium-ion batteries, laying the groundwork for longer-lasting, more powerful batteries for such applications as commercial electronics and electric vehicles.

A sponge formed from a solid wafer of silicon helps the material realize its potential to hold 10 times the amount of lithium ions than current materials used in rechargeable batteries. The material was developed by Rice University and Lockheed Martin.
Credit: Madhuri Thakur/Rice University

Researchers at Rice University and Lockheed Martin reported this month that they've found a way to make multiple high-performance anodes from a single silicon wafer. The process uses simple silicon to replace graphite as an element in rechargeable lithium-ion batteries, laying the groundwork for longer-lasting, more powerful batteries for such applications as commercial electronics and electric vehicles.

The work led by Sibani Lisa Biswal, an assistant professor of chemical and biomolecular engineering at Rice, and lead author Madhuri Thakur, a Rice research scientist, details the process by which Swiss cheese-like silicon "sponges" that store more than four times their weight in lithium can be electrochemically lifted off of wafers.

The research was reported online this month in the American Chemical Society journal Chemistry of Materials.

Silicon -- one of the most common elements on Earth -- is a candidate to replace graphite as the anode in batteries. In a previous advance by Biswal and her team, porous silicon was found to soak up 10 times more lithium than graphite.

Because silicon expands as it absorbs lithium ions, the sponge-like configuration gives it room to grow internally without degrading the battery's performance, the researchers reported. The promise that silicon sponges, with pores a micron wide and 12 microns deep, held for batteries was revealed in 2010 at Rice's Buckyball Discovery Conference by Thakur, Biswal, their Rice colleague Michael Wong, a professor of chemical and biomolecular engineering and of chemistry, and Steven Sinsabaugh, a Lockheed Martin Fellow. But even then Thakur saw room for improvement as the solid silicon substrate served no purpose in absorbing lithium.

In the new work, they discovered the electrochemical etching process used to create the pores can also separate the sponge from the substrate, which is then reused to make more sponges. The team noted that at least four films can be drawn from a standard 250-micron-thick wafer. Removing the sponge from the silicon substrate also eliminates a limiting factor to the amount of lithium that can be stored.

The team also found a way to make the pores 50 microns deep. Once lifted from the wafer, the sponges, now open at the top and bottom, were enhanced for conductivity by soaking them in a conductive polymer binder, pyrolyzed polyacrylonitrile (PAN).

The product was a tough film that could be attached to a current collector (in this case, a thin layer of titanium on copper) and placed in a battery configuration. The result was a working lithium-ion battery with a discharge capacity of 1,260 milliamp-hours per gram, a capability that should lead to batteries that last longer between charges.

The researchers compared batteries using their film before and after the PAN-and-bake treatment. Before, the batteries started with a discharge capacity of 757 milliamp-hours per gram, dropped rapidly after the second charge-discharge cycle and failed completely by cycle 15. The treated film increased in discharge capacity over the first four cycles -- typical for porous silicon, the researchers said -- and the capacity remained consistent through 20 cycles.

The researchers are investigating techniques that promise to vastly increase the number of charge-discharge cycles, a critical feature for commercial applications in which rechargeable batteries are expected to last for years.

Co-authors of the paper are postdoctoral researcher Roderick Pernites, alumnus Naoki Nitta and Lockheed Martin researcher Mark Isaacson.

The work was supported by the Lockheed Martin Advanced Nanotechnology Center of Excellence at Rice.


Story Source:

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


Journal Reference:

  1. Madhuri Thankur, Roderick Borong Pernites, Naoki Nitta, Mark Isaacson, Steven L Sinsabaugh, Michael S. Wong, Sibani Lisa Biswal. Freestanding macroporous silicon and pyrolyzed polyacrylonitrile as a composite anode for lithium ion batteries. Chemistry of Materials, 2012; 120706171653006 DOI: 10.1021/cm301376t

Cite This Page:

Rice University. "Toughened silicon sponges may make tenacious batteries." ScienceDaily. ScienceDaily, 16 July 2012. <www.sciencedaily.com/releases/2012/07/120716163238.htm>.
Rice University. (2012, July 16). Toughened silicon sponges may make tenacious batteries. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2012/07/120716163238.htm
Rice University. "Toughened silicon sponges may make tenacious batteries." ScienceDaily. www.sciencedaily.com/releases/2012/07/120716163238.htm (accessed April 23, 2014).

Share This



More Matter & Energy News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Air Force: $4.2B Saved from Grounding A-10s

Air Force: $4.2B Saved from Grounding A-10s

AP (Apr. 23, 2014) Speaking about the future of the United States Air Force, Chief of Staff Gen. Mark Welsh says the choice to divest the A-10 fleet was logical and least impactful. (April 23) Video provided by AP
Powered by NewsLook.com
Jets Fuel Jump in Boeing's Revenue

Jets Fuel Jump in Boeing's Revenue

Reuters - Business Video Online (Apr. 23, 2014) A sharp rise in revenue for commercial jets offset a decline in Boeing's defense business. And a big increase in deliveries lifted profitability. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? 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:
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