Subscribe free to our newsletters via your
. 24/7 Space News .




ENERGY TECH
Silicon sponge improves lithium-ion battery performance
by Staff Writers
Richland WA (SPX) Jul 11, 2014


PNNL researchers have developed a porous, sponge-like nanomaterial made of silicon that could help lithium-ion batteries run longer on a single charge by giving the batteries' electrodes the space they need to expand without breaking.

The lithium-ion batteries that power our laptops and electric vehicles could store more energy and run longer on a single charge with the help of a sponge-like silicon material.

Researchers developed the porous material to replace the graphite traditionally used in one of the battery's electrodes, as silicon has more than 10 times the energy storage capacity of graphite. A paper describing the material's performance as a lithium-ion battery electrode was published in Nature Communications.

"Silicon has long been sought as a way to improve the performance of lithium-ion batteries, but silicon swells so much when it is charged that it can break apart, making a silicon electrode inoperable," said Pacific Northwest National Laboratory Fellow Ji-Guang "Jason" Zhang. "The porous, sponge-like material we've developed gives silicon the room it needs to expand without breaking."

Room for improvement
Rechargeable lithium-ion batteries have two electrodes: one that's positively charged and made of lithium and another that's negative and typically consists of graphite. Electricity is generated when electrons flow through a wire that connects the two. To control the electrons, positively charged lithium atoms - which scientists call ions - shuffle from one electrode to the other through another path: the electrolyte solution in which the electrodes sit.

The chemistry of lithium-ion batteries limits how much energy they can store. To increase the battery's energy capacity, researchers are looking at new materials such as silicon. A lithium-ion battery with a silicon electrode could last about 30 percent longer than one with a graphite electrode. Today's average electric vehicle could drive about 130 miles on a single charge if it used a lithium-ion battery with PNNL's silicon electrode.

Unfortunately, silicon expands as much as three times in size when it charges, creating pressure within the material that causes it to break. Many scientists have attempted to make tiny, nano-sized battery components with the idea that the smaller size would give silicon enough room to expand, but these efforts haven't produced market-ready technologies.

A sponge solution
Zhang and his PNNL colleagues wondered if a sponge-like silicon electrode would do the trick. Others had etched pores into a silicon electrode's surface, but hadn't succeeded in creating holes throughout the material.

So they approached Michael Sailor, a University of California, San Diego chemist whose research includes using porous silicon to detect pollutants and deliver drugs, for help. PNNL used Sailor's method to create porous silicon - placing thin sheets in a chemical bath to etch out tiny holes throughout the material - and then coated the result with a thin layer of conductive carbon to make their electrodes.

Next, the team collaborated with materials scientist Chongmin Wang, who specializes in using in-situ transmission electron microscopes at DOE's EMSL, the Environmental Molecular Sciences Laboratory at PNNL.

Wang uses powerful microscopes to record close-up videos of tiny batteries, allowing researchers to better understand the physical and chemical changes that batteries undergo as they operate. Wang put the team's sponge-like, carbon-coated silicon electrode through a series of charges and discharges under the microscope's careful eye.

Space to grow
The team observed that while being charged, the new electrode mostly expanded into the empty spaces created by the material's porous structure. The outside shape of the electrode only expanded by 30 percent - much less than the 300 percent usually seen in silicon electrodes. And the new electrode didn't break down.

After more than 1,000 charge-and-discharge cycles, the electrode maintained more than 80 percent of its initial energy storage capacity. Next, Zhang and his colleagues plan to develop a larger prototype battery with their silicon sponge electrode. Part of that effort will involve creating a more streamlined production process so their new electrode can be made at a reasonable cost.

Xiaolin Li, Meng Gu, Shenyang Hu, Rhiannon Kennard, Pengfei Yan, Xilin Chen, Chongmin Wang, Michael J. Sailor, Ji-Guang Zhang and Jun Liu, "Mesoporous Silicon Sponge as an Anti-Pulverization Structure for High-Performance Lithium-Ion Battery Anodes," Nature Communications, July 8, 2014, DOI: 10.1038/ncomms5105.

.


Related Links
DOE/Pacific Northwest National Laboratory
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ENERGY TECH
USC scientists create new battery that's cheap, clean, rechargeable...and organic
San Diego CA (SPX) Jun 30, 2014
Scientists at USC have developed a water-based organic battery that is long lasting, built from cheap, eco-friendly components. The new battery - which uses no metals or toxic materials - is intended for use in power plants, where it can make the energy grid more resilient and efficient by creating a large-scale means to store energy for use as needed. "The batteries last for about 5,000 r ... read more


ENERGY TECH
NASA LRO's Moon As Art Collection Is Revealed

Solar photons drive water off the moon

55-year old dark side of the moon mystery solved

New evidence supporting moon formation via collision of 2 planets

ENERGY TECH
First LDSD Test Flight a Success

Rover Has Enough Energy for Some Late-Night Work

Curiosity travels through ancient glaciers on Mars

New Type of Dust in Martian Atmosphere Discovered

ENERGY TECH
Taiwan's tourism revenue hits record high in 2013

Fruit fly immunity fails with fungus after (space)flight

From Deep Sea to Deep Space

Commercial Crew Partners Focus on Testing, Analysis to Advance Designs

ENERGY TECH
Chinese moon rover designer shooting for Mars

Yutu designer's bittersweet

Are China's Astronauts Moonbound

Chinese scientists prepare for lunar base life support system

ENERGY TECH
NASA Television Coverage Set for Orbital-2 Mission to Space Station

Spot the Space Station looking at you

Closing the recycling circle

Space station astronauts wager friendly bet on USA vs. Germany match

ENERGY TECH
Eco-Friendly 'Angara' Rocket Installed On Plesetsk Launch Pad

Singapore launches its first nano-satellite

NASA's sounding rocket crashes into Atlantic

NASA aborts launch of OCO-2

ENERGY TECH
Discovery expands search for Earth-like planets

Astronomers discover most Earth-like of all exoplanets

Mega-Earth in Draco Smashes Notions of Planetary Formation

Kepler space telescope ready to start new hunt for exoplanets

ENERGY TECH
Even geckos can lose their grip

Platonic solids generate their four-dimensional analogues

Consider the 'Anticrystal'

Inspired by Nature, Researchers Create Tougher Metal Materials




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.