Energy News  
Latest Fuel Cell Material Advance Overcomes Low Humidity Conductivity Problem

The future is almost here...
by Staff Writers
Blacksburg VA (SPX) Sep 11, 2006
Fuel cells have been a workable technology for decades - but expensive and lacking in infrastructure. In recent years, researchers have addressed durability, manufacturability, and conductivity challenges in alternative proton exchange membrane (PEM) materials for fuel cells - bringing the hydrogen-based energy source closer to reality.

James McGrath, University Distinguished Professor of Chemistry with the Macromolecules and Interfaces Institute at Virginia Tech, announced his research group's latest development, a PEM material that retains conductivity during low humidity, during his plenary lecture at the Challenges for the Hydrogen Economy symposium during the 232nd National Meeting of the American Chemical Society (ACS) on September 10-14 in San Francisco.

Fuel cells convert chemical energy, usually from hydrogen, to electrical energy. In a PEM fuel cell, the critical exchange takes place through a thin water-swollen copolymer film that contains sulfonic acid (SO3H) groups. Electrons are peeled off by oxidation of the hydrogen atoms and hydrated protons pass through the film to combine with oxygen on the other side to form water as a byproduct.

The efficiency of the exchange process depends upon water, so efficiency - measured as proton conductivity - goes down as humidity goes down. "Up to now, a lot of water has been needed to assist the proton transfer process," said McGrath.

"But, in the desert, that is pretty inefficient." McGrath, chemical engineering Professor Don Baird, and their students demonstrated a method for creating a material with improved conductivity even at lower humidity. The U.S. Department of Energy awarded McGrath and Baird's groups $1.5 million over five years to advance the research.

Instead of stirring two kinds of reactive monomers, or small molecules, together to form a new random copolymer, the new material links blocks of two different short polymers in sequences. For example, he would link polymer W (loves water) and polymer d (dry but strong) into a chain this way: WWWWWdddddddWWWWWdddddddd.

The researchers can link a 10- to 50-unit block of a polymer containing acidic groups (SO3H) that like water (hydrophilic) to an equally long block of a polymer that has mechanical strength, thermal stability, and endurance, but hates water (hydrophobic). The chains self-assemble into flexible thin films. Under an atomic force microscope, the film's swirling surface looks like a fingerprint, with light ridges and dark channels.

It turns out that the soft hydrophilic polymer forms the dark channels where water is easily absorbed so that the entire film - or proton exchange membrane (PEM) - has an affinity for water transport that is two to three times higher than the present commercially available PEM.

In addition to making PEM materials with better qualities, another goal of the research is to make PEM materials that can be easily manufactured. The self-assembling nature of the block copolymer material into a nanocomposite film is an important attribute.

In addition, Baird is working on processing the film from powders using a reverse roll coater, equipment commonly available in the coatings industry but not yet being used to produce PEM material. McGrath will present the paper, "Progress in alternate proton exchange membrane materials for fuel cells (Fuel 3)," at 10:15 a.m. Sunday, Sept. 10, in the Golden Ballroom of the Sheraton Palace.

Graduate students in McGrath's group will present details regarding the alternative PEM materials during the Division of Fuel Chemistry symposium. The first public presentation of most of the atomic force microscope images of the new polymer will be during a presentation by Virginia Tech graduate student Anand Badami.

The paper, Morphological analysis of molecular weight effects based on random and multiblock copolymers for fuel cells, is coauthored by fellow graduate students in Virginia Tech's macromolecular science and engineering program Hae-Seung Lee, Yanxiang Li, Abhishek Roy, and Hang Wang, and McGrath.

Yanxian Li will report on the synthesis of the new material in the paper, "Synthesis and characterization of partially fluorinated poly(arylene ether ketone)- poly(arylene ether sulfone) (6FK- BPSH) multiblock copolymers containing sulfonate groups for proton exchange membrane," co-authored by fellow students Roy, Badami, and Juan Yang, postdoctoral associate Zhongbiao Zhang, and McGrath.

And Abhishek Roy reports on measurements of cell conductivity in the paper, "Transport properties of multiblock hydrophilic-hydrophobic proton exchange membranes for fuel cells," co-authored by Hae-Seung Lee, Badami1, Xiang Yu, Li, chemistry professor Thomas E. Glass, and McGrath.

Community
Email This Article
Comment On This Article

Related Links
Virginia Tech
Powering The World in the 21st Century
Powering The World in the 21st Century at Energy-Daily.com



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


Researchers Aim To Enhance Air Vehicle Systems
Arlington VA (AFPN) Sep 10, 2006
Air Force Office of Scientific Research officials here recently awarded the University of Washington and three partner universities a grant worth approximately $6 million over five years to study the design of air vehicles capable of collecting and storing solar and heat energies.







  • Researchers Aim To Enhance Air Vehicle Systems
  • Chemical Screening system helps evaluate PEM Fuel Cell Materials
  • High-Value Chemicals Produced From Ethanol Feedstocks Could Boost Biorefinery Economics
  • Latest Fuel Cell Material Advance Overcomes Low Humidity Conductivity Problem

  • US Reactor Security Queried: Part Two
  • Australia Could Export Uranium To China Within Months
  • Russia To Sell Nuke Fuel To South Africa
  • Understanding Reactor Security Fears In The 21st Century

  • NASA Experiment Finds Possible Trigger For Radio-Busting Bubbles
  • California's Model Skies
  • ESA Picks SSTL To Develop Atmospheric CO2 Detector
  • Faster Atmospheric Warming In Subtropics Pushes Jet Streams Toward Poles

  • Fires Rage As Haze Thickens In Borneo
  • Large-Scale Farming Now Causes Substantial Forest Loss in Amazon
  • The Subtleties Of Tropical Forest Demise
  • NASA Satellites Can See How Climate Change Affects Forests

  • China Rejects Claims Of GM Rice Entering EU Foods
  • GM Chinese Rice Maybe Contaminating European Food
  • French Police Arrest Three As Hundreds Try To Destroy GM Crops
  • Japanese Sushi Infatuation Straining Atlantic Tuna Stocks

  • Real-Time Traffic Routing From The Comfort Of Your Car
  • Real-Time Traffic Routing From The Comfort Of Your Car
  • British Police Force To Introduce Greener Cars
  • Two New Segway Models Offered

  • US Sanctions On Russia Could Hurt Boeing
  • Boeing Puts Aircraft Market At 2.6 Trillion Dollars
  • Innovative Solutions Make Transportation Systems Safer Secure and Efficient
  • Joint Strike Fighter Is Not Flawed Finds Australian Government

  • Could NASA Get To Pluto Faster? Space Expert Says Yes - By Thinking Nuclear
  • NASA plans to send new robot to Jupiter
  • Los Alamos Hopes To Lead New Era Of Nuclear Space Tranportion With Jovian Mission
  • Boeing Selects Leader for Nuclear Space Systems Program

  • The content herein, unless otherwise known to be public domain, are Copyright 1995-2006 - SpaceDaily.AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA PortalReports are copyright European Space Agency. All NASA sourced material is public domain. Additionalcopyrights 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 SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement