Featured Research

from universities, journals, and other organizations

Scientists create novel silicon electrodes that improve lithium-ion batteries

Date:
June 4, 2013
Source:
Stanford University
Summary:
Scientists have dramatically improved the performance of lithium-ion batteries by creating novel electrodes made of silicon and conducting polymer hydrogel, a spongy material similar to that used in contact lenses and other household products. The scientists developed a new technique for producing low-cost, silicon-based batteries with potential applications for a wide range of electrical devices.

This is an illustration of a new battery electrode made from a composite of hydrogel and silicon nanoparticles (Si NP). Each Si NP is encapsulated in a conductive polymer surface coating and connected to a three-dimensional hydrogel framework.
Credit: Yi Cui, Stanford University

Stanford University scientists have dramatically improved the performance of lithium-ion batteries by creating novel electrodes made of silicon and conducting polymer hydrogel, a spongy material similar to that used in contact lenses and other household products.

Related Articles


Writing in the June 4 edition of the journal Nature Communications, the scientists describe a new technique for producing low-cost, silicon-based batteries with potential applications for a wide range of electrical devices.

"Developing rechargeable lithium-ion batteries with high energy density and long cycle life is of critical importance to address the ever-increasing energy storage needs for portable electronics, electric vehicles and other technologies," said study co-author Zhenan Bao, a professor of chemical engineering at Stanford.

To find a practical, inexpensive material that increases the storage capacity of lithium-ion batteries, Bao and her Stanford colleagues turned to silicon -- an abundant, environmentally benign element with promising electronic properties.

"We've been trying to develop silicon-based electrodes for high-capacity lithium-ion batteries for several years," said study co-author Yi Cui, an associate professor of materials science and engineering at Stanford. "Silicon has 10 times the charge storage capacity of carbon, the conventional material used in lithium-ion electrodes. The problem is that silicon expands and breaks."

Studies have shown that silicon particles can undergo a 400-percent volume expansion when combined with lithium. When the battery is charged or discharged, the bloated particles tend to fracture and lose electrical contact. To overcome these technical constraints, the Stanford team used a fabrication technique called in situ synthesis polymerization that coats the silicon nanoparticles within the conducting hydrogel.

This technique allowed the scientists to create a stable lithium-ion battery that retained a high storage capacity through 5,000 cycles of charging and discharging.

"We attribute the exceptional electrochemical stability of the battery to the unique nanoscale architecture of the silicon-composite electrode," Bao said.

Using a scanning electron microscope, the scientists discovered that the porous hydrogel matrix is riddled with empty spaces that allow the silicon nanoparticles to expand when lithium is inserted. This matrix also forms a three-dimensional network that creates an electronically conducting pathway during charging and discharging.

"It turns out that hydrogel has binding sites that latch onto silicon particles really well and at the same time provide channels for the fast transport of electrons and lithium ions," explained Cui, a principal investigator with the Stanford Institute for Materials and Energy Sciences at the SLAC National Accelerator Laboratory. "That makes a very powerful combination."

A simple mixture of hydrogel and silicon proved far less effective than the in situ synthesis polymerization technique. "Making the hydrogel first and then mixing it with the silicon particles did not work well," Bao said. "It required an additional step that actually reduced the battery's performance. With our technique, each silicon nanoparticle is encapsulated within a conductive polymer surface coating and is connected to the hydrogel framework. That improves the battery's overall stability."

Hydrogel primarily consists of water, which can cause lithium-ion batteries to ignite -- a potential problem that the research team had to address. "We utilized the three-dimensional network property of the hydrogel in the electrode, but in the final production phase, the water was removed," Bao said. "You don't want water inside a lithium-ion battery."

Although a number of technical issues remain, Cui is optimistic about potential commercial applications of the new technique to create electrodes made of silicon and other materials.

"The electrode fabrication process used in the study is compatible with existing battery manufacturing technology," he said. "Silicon and hydrogel are also inexpensive and widely available. These factors could allow high-performance silicon-composite electrodes to be scaled up for manufacturing the next generation of lithium-ion batteries. It's a very simple approach that's led to a very powerful result."


Story Source:

The above story is based on materials provided by Stanford University. The original article was written by Mark Shwartz. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hui Wu, Guihua Yu, Lijia Pan, Nian Liu, Matthew T. McDowell, Zhenan Bao, Yi Cui. Stable Li-ion battery anodes by in-situ polymerization of conducting hydrogel to conformally coat silicon nanoparticles. Nature Communications, 2013; 4 DOI: 10.1038/ncomms2941

Cite This Page:

Stanford University. "Scientists create novel silicon electrodes that improve lithium-ion batteries." ScienceDaily. ScienceDaily, 4 June 2013. <www.sciencedaily.com/releases/2013/06/130604094703.htm>.
Stanford University. (2013, June 4). Scientists create novel silicon electrodes that improve lithium-ion batteries. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2013/06/130604094703.htm
Stanford University. "Scientists create novel silicon electrodes that improve lithium-ion batteries." ScienceDaily. www.sciencedaily.com/releases/2013/06/130604094703.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

Toyota's Hydrogen Fuel-Cell Green Car Soon Available in the US

AFP (Nov. 21, 2014) Toyota presented its hydrogen fuel-cell compact car called "Mirai" to US consumers at the Los Angeles auto show. The car should go on sale in 2015 for around $60.000. It combines stored hydrogen with oxygen to generate its own power. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Google Announces Improvements To Balloon-Borne Wi-Fi Project

Google Announces Improvements To Balloon-Borne Wi-Fi Project

Newsy (Nov. 21, 2014) In a blog post, Google said its balloons have traveled 3 million kilometers since the start of Project Loon. Video provided by Newsy
Powered by NewsLook.com
NSA Director: China Can Damage US Power Grid

NSA Director: China Can Damage US Power Grid

AP (Nov. 20, 2014) China and "one or two" other countries are capable of mounting cyberattacks that would shut down the electric grid and other critical systems in parts of the United States, according to Adm. Michael Rogers, director of the National Security Agency and hea Video provided by AP
Powered by NewsLook.com
Latest Minivan Crash Tests Aren't Pretty

Latest Minivan Crash Tests Aren't Pretty

Newsy (Nov. 20, 2014) Five minivans were put to the test in head-on crash simulations by the Insurance Institute for Highway Safety. 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