New MOF-based Membrane Enables Higher-Temperature PEM Fuel Cells
19 October 2009
|SEM images of the MOF- material [β-PCMOF2(Tz)0.45], illustrating a rod-shape morphology. Source: Hurd et al. (2009), Supplementary Material. Click to enlarge.|
Researchers at the University of Calgary have developed a new membrane based on metal-organic frameworks (MOFs) (earlier post) that enables a polymer electrolyte membrane (PEM) fuel cell to operate at higher temperatures—an important step in terms of increasing the efficiency and decreasing the cost of PEM fuel cells.
A paper on the development by George Shimizu, Jeff Hurd, Ramanathan Vaidhyanathan and Venkataraman Thangadurai of the University of Calgary, and Christopher Ratcliffe and Igor Moudrakovski of the Steacie Institute for Molecular Sciences, National Research Council, was published online 18 October in the journal Nature Chemistry. Shimizu filed a patent with the US patent office last year.
MOFs—compounds consisting of metal-oxide clusters connected by organic linkers—are exciting materials that couple porosity, diversity and crystallinity. However, most work on MOF applications has focused on properties intrinsic to the empty frameworks—e.g., for storage of hydrogen, as one example (e.g., earlier post). Shimizu and his colleagues instead focused on the use of guest molecules within the framework to control other functions.
This research will alter the way researchers have to this point perceived candidate materials for fuel cell applications.
They report on Na3(2,4,6-trihydroxy-1,3,5-benzenetrisulfonate) (named β-PCMOF2), a MOF that conducts protons in regular one-dimensional pores lined with sulfonate groups. To confirm its potential as a gas separator membrane, the partially loaded MOF (β-PCMOF2(Tz)0.45) was incorporated into a H2/air membrane electrode assembly. The resulting membrane proved to be gas tight, and gave an open circuit voltage of 1.18 V at 100 °C.
Currently, PEM fuel cells can produce energy from hydrogen below 90 °C, just under the boiling point of water. With Shimizu’s material, energy can be produced at a higher temperature, up to 150 °C. This could ultimately make the fuel cell cheaper to produce because at a higher temperature less expensive metals can be used to convert hydrogen into energy. Reactions at a higher temperature would also be faster thus increasing efficiency.
Ours is an entirely new approach that strikes a balance between having a regular molecular structure and mobile components all while showing genuine promise of application.Jeff Hurd
Kevin Colbow, director of research and development at hydrogen fuel cell manufacturer Ballard Power Systems, calls the work significant. “We believe that further improvement on conductivity and robustness of these materials could provide next generation membranes for PEM fuel cells.”
Jeff A. Hurd, Ramanathan Vaidhyanathan, Venkataraman Thangadurai, Christopher I. Ratcliffe, Igor L. Moudrakovski & George K. H. Shimizu (2009) Anhydrous proton conduction at 150 °C in a crystalline metal–organic framework. Nature Chemistry doi: 10.1038/nchem.402
There are no doubts that better and lower cost FC will be built by 2020/2030.
Will it ever be enough to offset the cost of a worldwide hydrogen distribution network?
BEVs with improved lower cost batteries (e-storage units) with home and commercial chargers is a much neater solution.
Posted by: HarveyD | 19 October 2009 at 08:18 AM
Uh harvey... they are already building the damn network anyway as alot of other things need h2 as well. The number of miles of h2 pipeline is growing rapidly and none of that is from car use. Also alot of work on better ways to truck h2 has been done and alot of that is also not about car use.
Posted by: wintermane2000 | 19 October 2009 at 09:05 AM
Hydrogen is used in refineries but most of it is created by reforming natural gas. J would say that it is easier for a station to put in charging than hydrogen storage and dispensing.
It is very easy for them to add E85 pumps and the cost per pump has been established. This is why I favor FFVs and cellulose E85.
Posted by: SJC | 19 October 2009 at 03:48 PM
E85, even cellulose E85, isn't going to work until America learns to use a lot less fuel(whichever fuel that is) when driving. The land requirements are just too great. 'The U.S. has the land, water and transportation resources necessary to make a whole lot of cellulosic ethanol. Enough, in fact, to replace one-third of your gasoline needs by 2030' but replacing 85%? Dream on.
And the down side?
Posted by: ai_vin | 19 October 2009 at 04:32 PM
Er am I missing something?
Pems get their hydrogen from any hydrogen rich source hydrogen infrastructure not required....
HowStuffWorks "How Fuel Cells Work" We'll detail how polymer electrolyte membrane fuel cells (PEMFC) work and examine how ... A fuel cell converts the chemicals hydrogen and oxygen into water, ...
auto.howstuffworks.com/fuel-efficiency/...fuels/fuel-cell.htm - Cached - Similar
Posted by: arnold | 19 October 2009 at 04:54 PM
What's the big deal with this announcement.
BASF already has a membrane based on a polymer called polybenzimid-azole known by its trade name Celtec. The membrane is a real product that can be purchased presently. It operates at up to 180 degrees C and is cheaper than traditional membranes. Fuel cells made with this material are air cooled. They don't require humidifiers, water pumps, tanks, valves, and cleaning systems. Super pure hydrogen is also unnecessary. A fuel cell system which delivers 25 kW of electrical power is being tested on the Anteres glider plane in Germany at this time.
Check it out on the BASF web site and designnews.com.
Posted by: Mannstein | 19 October 2009 at 05:18 PM
The Anteres electric powered glider has a range of 750 km using the BASF fuel cell and 100km using lithium ion batteries of the same weight.
Posted by: Mannstein | 19 October 2009 at 05:48 PM
"any hydrogen rich source"
Last time I looked, PEM fuel cells require hydrogen...period. SOFCs can take methane directly, but PEM fuel cells require H2.
Cellulose E85 can come from biomass. There are ONE BILLION tons annually that can produce 100 billion gallons of biofuel without extra land.
Type "Billion Ton Study" into a search engine if you want to see.
Posted by: SJC | 19 October 2009 at 07:37 PM
Brain explosion, too many acronyms.Ouch!
Posted by: arnold | 19 October 2009 at 08:53 PM
While all pem fuel cells require h2 the newer ones dont require as clean a source of h2 as the older ones did and they run at up to 180 c. They are cheaper to make and far far more durable.
Posted by: wintermane2000 | 20 October 2009 at 04:27 AM
That might be an advantage if you are going to reform methanol into H2 on the vehicle. The NECAR series from Daimler did this and worked well. If whatever is left in the H2 after reforming can be better tolerated by the fuel cell, it could improve the life span of the system.
Posted by: SJC | 20 October 2009 at 07:05 PM
Well, e.g. the cost for a hydrogen network for fuel cell cars in Germany would cost about 1.5 billions Euro. Compared to the 100 billions the government spend for the HRE bank is that just a droplet onto a hot stone.
For the US the hydrigen infrastrucutre would cost less 10% of the cost for the Irak war or less than the oil pipeline down from Alaska.
Posted by: Skippi | 20 October 2009 at 10:42 PM
The funny thing alot of idiots are forgetting is other then the initial rollout of a sparce network of stations everything else is paid for by the hydrogen itself. So why do you realy care?
Posted by: wintermane2000 | 21 October 2009 at 05:23 AM