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Researchers discovered ideal particles size for catalyst inside a fuel cell

Researchers are working hard to develop hydrogen fuel cells as a viable method of powering automobiles. The problem with this type of fuel cell at this point is that the storage of hydrogen is difficult and the fuel cells don’t last as long as manufacturers would like.

Two scientists from the University of Wisconsin-Madison have made an important stride in making hydrogen fuel cell vehicles more viable. The two scientists -- Professor Dane Morgan and PhD student Edward Holby -- have designed a computational model that can optimize one of the most important components of a fuel cell, possibly leading to a longer usable life.

The computational model is being used to investigate how the particle size of a material relates to the overall stability of the material. The researchers are using the model to look at the most efficient and effective particle size for the catalyst inside the fuel cell.

The fuel cell catalyst is typically made from platinum or platinum alloy. The catalyst is used to aid the reaction between the protons, electronics, and oxygen at the cathode inside the cell. Platinum is able to withstand the corrosive fuel cell environment but is costly and not available in abundance.

Platinum particles used inside current fuel cell catalysts are as small as two nanometers across. The tiny particles offer enough surface area for the reaction, but are quickly destroyed and degrade rapidly. The degradation of the catalyst means that the fuel cell doesn't last long. The Department of Energy figures that a fuel cell needs to last for 7 months of continuous use for automotive needs.

The computational model developed by the pair has shown that the ideal particle size for the catalyst is about 20 atoms across, roughly twice as large as the particles inside fuel cells today. At the 20-atom size, the particles degrade much slower and allow the fuel cell to function significantly longer.

Morgan likens the stability of larger particles to cheese, "When you leave a large chunk of cheese out and the edges get crusty, the surface is destroyed, but you can cut that off and there is still a lot of cheese inside that is good. But if you crumble the cheese into tiny pieces and leave it out, you destroy all of your cheese because a larger fraction of the cheese is at the surface."

Another group of researchers made a breakthrough in July with the potential to make storing hydrogen for fuel cells more efficient.



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Shows some promise
By HrilL on 9/18/2009 11:52:20 AM , Rating: 2
Fuel cells are coming a log way but they still need a lot of work. They are the key to switching to all electric vehicles because our current battery tech doesn't cut it and the price is far too high. They are also currently harmful and hard to dispose of. We should be spending more money on this kind of research.




RE: Shows some promise
By barrychuck on 9/18/09, Rating: 0
RE: Shows some promise
By acase on 9/18/2009 2:29:06 PM , Rating: 2
While I am sure it is plausible you know what you are talking about, I certainly didn't get anything out of what you tried to type. How about a better organized rant, and, I don't know, maybe some actual facts backing it? I really am interested in the negatives, since I've mainly heard about the positives.


RE: Shows some promise
By quiksilvr on 9/18/2009 2:46:17 PM , Rating: 2
Here you go.

Hydrogen Fuel Cell:
PROS
-Fuel source highly abundant
-No harmful emissions
-Lots of energy in fuel, meaning better range with smaller engines

CONS
-Much more expensive
-Hydrogen takes a lot of energy to process from water and even more energy to store securely
-Requires dedicated fueling stations
-Very fragile. A minor collision could completely damage the engine costing thousands of dollars

Electric cars:
PROS
-Fuel source highly abundant
-No harmful emissions
-Much cheaper
-Available now in a much wider variety
-Can be refueled anywhere that has a plug
-More durable in a crash

CONS
-Fuel source may be created from other materials that do leave emissions
-Lithium Ion batteries do not last forever and eventually have to be replaced in 5 to 10 years
-Range depends on battery capacity, meaning more weight and more price.

All in all, hydrogen fuel cells would be a great idea to convert water into energy, but I feel that it isn't the best solution for a car. What's the point of having a hydrogen fuel cell in your car that transmits energy to your electrical engine when you can just connect it to a battery?

Furthermore, lithium batteries are soon going to have an evolutionary jump into nanowire batteries ( http://en.wikipedia.org/wiki/Nanowire_battery ) giving way to much higher density batteries in a smaller package.


RE: Shows some promise
By Triple Omega on 9/18/2009 3:21:01 PM , Rating: 2
Your Pro-Electric conclusion only holds true if the advancements in battery capacity AND battery charge time come in the near future and are great enough to make electric a 1:1 replacement for fossil fuels.

If the capacity isn't raised to high enough levels, business applications will be severely diminished as continues operation for extended periods will be impossible.

If the charge time isn't significantly reduced, people won't be able to make a quick recharging stop, which will effectively prevent them from choosing a destination beyond where one charge can take them.

I have no doubt that electric is the future, but we might have to get there through hydrogen.


RE: Shows some promise
By quiksilvr on 9/18/2009 5:13:16 PM , Rating: 2
If you read the nanowire battery article on Wikipedia, you will see that due to its incredible energy density increases the surface area, which therefore allows for fast charging and discharging. In fact, HP has already developed a similar battery already and will make it commercial within a year or so.

You are forgetting that people can charge their cars while at home making it less necessary for charging stations in the first place. You only really need to charge it up at parking lots and they are already starting to place charging stations at these places (something that is much much easier to do than putting a hydrogen station).

Hydrogen has its benefits, but not on the ground.


RE: Shows some promise
By drmo on 9/18/2009 5:46:02 PM , Rating: 2
That is pretty good. The cost will be higher, but once mass production lowers the costs sufficiently, it seems a battery with 10X the storage capacity would make the other technologies pointless. The Volt would be able to go 400 miles (with its current size battery), so no need for a backup gas motor, and quick charges would mean you could have a smaller battery, less weight, etc.

Then we can be back to driving massive SUVs and trucks, and use four electric motors.... I wonder what kind of power you could get with that.


RE: Shows some promise
By AnnihilatorX on 9/19/2009 7:19:30 AM , Rating: 2
It is entirely possible to put electrolysis device in a hydrogen car that consumes water as fuel. When you charge such a car you put water as well as plug it to electricity grid. Though this is certainly more complex and require expensive technology despite being currently available.

Much more research is definitely needed.

Though I say skip hydrogen fuel cells and go for fusion fuel cells :P


RE: Shows some promise
By Triple Omega on 9/19/2009 10:01:22 AM , Rating: 2
1) I did read that nanowire article(I actually read far more about it months ago.), but a theoretical/experimental technology is not a fully developed technology. There is no way to know for sure how long it's actually going to take to get there in mass-production or if the promised numbers will be attainable at all. If it takes too long or isn't good enough in the end, hydrogen might be the only option.

2) Why are you assuming I forgot about charging at home? I actually said:
quote:
If the charge time isn't significantly reduced, people won't be able to make a quick recharging stop, which will effectively prevent them from choosing a destination beyond where one charge can take them.
Meaning they can charge at home, then drive to their destination and charge there, then drive back. They can't however drive further then where one charge will take them as recharging mid-travel will then be necessary and that will take unacceptably long.

3) Also you have to take industrial vehicles into account. They often cost a lot of money if they're doing nothing, so large capacity and quick charge is vital in this sector. The catch here is that the big money is in the industry, not the consumers. Meaning whichever side the industry choses will get a massive financial boost and likely be able to conquer the consumer market as well.


RE: Shows some promise
By namechamps on 9/21/2009 8:27:27 AM , Rating: 2
Average EV battery pack is ~10kwh

Say charging system is 200V.

10kwh / 200V = 50ah.

So if wanted the vehicle to charge in 1 hour it would need to push 50 amps.
If you wanted the vehicle to charge in 20 minutes it would need ot push 150 amps.

If you wanted the vehicle to charge in 5 minutes it would need to push 600 amps.

Now 600 amp connectors do exist but they are high cost industrial connectors not something that you put in a consumer device where people are distracted while refueling. They also tend not to be high use connectors. An average fuel pump may be used 2-3 million times per year. High amp industrial connectors tend to be inspected routinely by experts.

So the first time a consumer attempt to charge their EV with a damage plug or receptacle and electrocutes themselves the except multi million dollar lawsuit.

No way is any company going to open themselves up to a lawsuit by pushing that much current.

Also for home charging it simply is not possible. House wiring can't handle that much current. Hell many house mains can't handle that much current.


RE: Shows some promise
By drmo on 9/18/2009 5:36:46 PM , Rating: 2
I'm not sure the cost issue is as much a problem anymore. I thought the GM Volt battery was around 100 kW and cost about $10,000. Now, according to this: http://en.wikipedia.org/wiki/Fuel_cell
fuel cells are down to $73 per kW, which would mean a 100 kW fuel cell would be $7300 to produce. But you also have to make the hydrogen, so the fuel is more expensive for now. If home reformers (from natural gas) become cheap, then that will help, because NG is cheaper than electricity.

As far as the other poster, I think the point was that a battery loses much less energy in its energy sequence than a fuel cell:
Electric: charge-discharge-motor sequence (93%+ electric line efficiency; 90% efficiency charge-discharge; then about 89%+ efficiency in battery to propulsion).
Fuel cell: (up to 50% for electric hydrolysis efficiency, up to 80% for natural gas to hydrogen conversion efficiency; then 40-60% fuel cell to motor efficiency).

Note, an internal combustion engine gets about a maximum of 30% efficiency. So a fuel cell is better than combustion anyway, but not more efficient than an EV.


RE: Shows some promise
By safcman84 on 9/21/2009 6:17:48 AM , Rating: 1
You forgot two of the main negatives of electric cars:

1) You need to plug them in and recharge them. Sound simple? Ever wondered where the electricity came from? Coal-power stations? Oil-power stations? Nuclear? Electric cars = zero emissions? Nope, dont think so.

2) Lithium-ion. Great stuff, until you need to get rid of it. Extremely toxic and therefore difficult to get rid of. Most of them will probably end up being dumped. so again, so much for the environmentally friendly thing.

Oh, Hydrogen might be expensive to produce now, as you need electricity to produce hydrogen from water but there are new processes that are becoming available (Bacteria produced hydrogen - basically recycling sewage water - for example).


RE: Shows some promise
By Yeco on 9/19/2009 8:19:15 AM , Rating: 2
But it is still beter then a combustion engine!

And there are other ways to make hydrogen then through hydrolysis.


RE: Shows some promise
By randomly on 9/21/2009 9:48:49 AM , Rating: 2
Hydrogen fuel cell powered cars have a number of problems that are glossed over because they make a great 'Pollution free, Eco-Green' poster child. Few people actually in the industry believe hydrogen fuel cell cars will be deployed in any meaningful way for many many decades if ever. However they make a great marketing angle for getting 'Green' points for corporations, researchers can get grant money, news and magazines get wonderful articles about savior technologies.

1) There is no efficient way to make hydrogen other than reforming of natural gas at 80% efficiency. This does nothing to get you away from fossil fuels. In an MIT study even projecting improvements to fuel cells to 2020 a simple diesel hybrid car would still have better well to wheels performance than a fuel cell car.

2) Electrolysis is only about 50% efficient so using any source of electrical energy to make hydrogen to power your vehicle is grossly inefficient. 50% loss of energy in making the hydrogen, 12%-30%(compressed gas to liquid respectively)loss in energy in storing the hydrogen, 50% loss of energy in the fuel cell recovering the electricity. For an overall energy storage efficiency of less than 25%.

Compared to batteries with an overall storage efficiency in excess of 90%. That's 4 times the energy and energy cost to run a fuel cell vehicle vs a battery powered one.
That poor cycle efficiency means that you are always better off using your electrical power to do something else with until all your fossil fuel electrical power generation has been eliminated. Even then the economics of it weigh against fuel cells unless power costs get very cheap.

3)Hydrogen storage and transportation cost are quite high. Because pumps pump volume not density the costs of transporting hydrogen are energy intensive because even under very high pressure hydrogen has a very low density. This means it takes significant amounts of energy to pump the stuff around. You also would need to lay all new pipeline because existing pipeline is susceptible to hydrogen embrittlement. If you transport it by truck the low density hits you again. It takes 20 tanker trucks with the corresponding costs and energy usage to transport an equivalent amount of fuel as one gasoline tanker truck. Because you transport it as a compressed gas, every time you transfer it from one container to another you again incur pumping losses. If you deliver electical power to a 'gas station' and use electrolysis locally you need to lay all new powerlines to handle the load, you need to dissipate enormous amounts of heat at the station (half the energy put into electrolysis ends up as heat), and you spend another 12% of your energy compressing the gas (which generates even more heat). This become one very expensive gas station to build and maintain.
Hydrogen adsorption in solid materials is no better because usually the more hydrogen the material can adsorb the harder it gloms on to the hydrogen and the more energy it takes to get it back out again and you end up better off with compressed gas again.
4) Still huge problems with fuel cells. They are very expensive. They are delicate, you have to carefully control the amount of water in the system, if it dries out it destroys it. The catalysts are susceptible to poisoning from carbon monoxide and sulfur compounds in the air. They also don't last long enough and break down too rapidly.

Even though all these technical problems may be solvable in the future the basic thermodynamic efficiency limits of the overall energy cycle are constrained by theoretical limits, you just can't improve it all that much.

As to batteries
1) The waste disposal problem is largely a red herring. The batteries would be recycled. The retained value of large lithium batteries from cars would be in the hundreds of dollars for the materials alone. End of life capacity is considered to be 80%, the value of a still functional battery with 80% capacity would be in excess of a thousand dollars. Nobody is going to dump them in land fills, and if they do somebody is going to pick them up and sell them.

2) The Silicon nanowire lithium battery thing is constantly misrepresented by the press. The density was only 10x on the very first charge, for repeated cycles it was 8x. But the real deception is that this is for the Anode of the battery only, not the cathode. Current Anode materials (usually graphite) already have several times more capacity than the cathode materials. Even if the silicon nanowires could store 100X the density it wouldn't improve the capacity of lithium batteries more than about 1/3 because the bottle neck is the cathode materials.
But of course that doesn't make as sensational a story, and it's not about truth in science, it's about readership.


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