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Researchers Design Lithium-Coated Buckyball with 13 wt.% Hydrogen Storage

Jena_hydrogen_storage
A lithium-coated fullerene (buckyball) as a potential material for hydrogen storage. Yellow represents lithium atoms, and black represents carbon atoms. Click to enlarge.

Researchers at Virginia Commonwealth University have described a potential new hydrogen storage system for vehicular applications based on lithium-coated buckyballs. The new material promises a gravimetric storage density of 13 wt.%&mdash

As reported in the 6 July online edition of the Journal of the American Chemical Society, the team designed a theoretical buckyball—fullerene containing 60 carbon atoms—in which Li atoms are capped onto the pentagonal faces of the fullerene. Each lithium atom can bond with five hydrogen molecules, resulting in a storage of 60 hydrogen molecules per buckyball.

We are going to face an energy crisis at some point in the future. It’s not a question of if, but when. We need an energy source that is abundant, cost effective and renewable, burns clean and does not pollute. Today, approximately 75 percent of the oil currently available is used for transportation alone. Any solution to the energy crisis has to take into account the amount of energy we spend on transportation.

The biggest hurdle in a hydrogen economy is to find materials to store hydrogen. The storage materials in question need to have the ability to store hydrogen and allow us to take it out, which means the system must be reversible and operate under moderate temperatures and pressures.

—Puru Jena, lead author

Theoretical and experimental work by other researchers has proposed using titanium-coated buckyballs for hydrogen storage. However, those researchers observed that the titanium atoms had a tendency to react with each other and form clusters on the surface of the buckyball. Once clustering takes place, the properties of the buckyball are no longer effective for storing hydrogen in large quantities.

The Department of Energy is targeting storage with a total system gravimetric storage density of 9 wt.% and volumetric density of 70 grams/liter.

The material that we have designed is capable of storing hydrogen at a gravimetric density of 13 weight percent – so it exceeds the industry target. Also, the volumetric density is approximately twice that of liquid hydrogen. This theoretical work has promise, provided one can make it in large enough quantities.

—Puru Jena

Jena is currently collaborating with scientists who will conduct experiments to prove that hydrogen can be stored in the lithium buckyballs. Furthermore, these investigators will determine the necessary temperature and pressure conditions for storage and removal of hydrogen from the lithium buckyballs, and how to produce these materials in large quantities.

This research was supported by a grant from the US Department of Energy. Jena collaborated with Qiang Sun, Ph.D., who is affiliated with the INEST Group, Research Center at Phillip Morris USA; Qian Wang, Ph.D, a research associate professor at VCU; and Manuel Marquez, Ph.D., with the Research Center at Phillip Morris.

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Comments

JimO

When I see these stories about nanotech hydrogen storage system I always wonder if this is a case where if you could do that economically you could also economically make a nanotech battery or capacitor that could store energy in sufficient density and with rapid enough charging that you would no longer need to use h2.

Is my guess correct? Or will it be significantly easier to make the h2 storage device?


marcus

This is also the question I would like to ask. How do the current and projected energy densities for Hydrogen storage compare with current and projected batteries?

Sid Hoffman

Forget storage, let's talk production. We know how to produce electricity cheaply and cleanly (nuclear, hydro, solar, wind) but producing hydrogen either needs to come from natural gas or by using far more electricity to produce hydrogen and store/pressurize it, and so on. Hydrogen's only real advantage in the context of cars is that many claim it can be refueled in a matter of minutes, rather than the 4-6 hours you often see quoted for batteries.

sjc

You could make hydrogen out of biomass and sequester the CO2 through pipes back into spent wells. That way, you would be better than CO2 neutral.

You would want the hydrogen in the car and not making electricity to charge batteries. If making electricity is 40% efficient, transimssion is 90% and battery storage is 80% efficient you would have : .4 X .9 X .8 = .288 or 28.8%

Patrick

The last time I read of "mass-producing" carbon nanotubes they were talking about production with a cost of around $1000 per gram. I doubt these fullerene storage systems are going to be much more cost effective.

K

H or H2 (notice the abstract says atoms, not molecules) which is it?

Hydrogen may continue to elude our magicans reaching into hats. For a while.

Anyone know how easily the hydrogen can be taken out of these solid state storage materials? My completely uninformed mind wonders why a stored hydrogen atom would want to flow out.

Sid Hoffman

There's no such thing as mass production of hydrogen from biomass either. The bottom line is that transportation fuels are not really the way of the future at our current and projected global consumption levels. Hydrogen, ethanol, and biodiesel cannot be produced on the order of 85 million barrels a day in the absense of oil.

Harvey D.

According to Tesla's group and others, the hydrogen fuel cell WTW efficiency is much lower then the pure EVs and PHEVs equipped qith a large enough battery pack.

Why spend so much energy and resources on a difficult, extremely expensive, not so efficient process?

Let's re-route the $$ billions hydrogen R & D funds to further improve and lower the production cost of the Altair-A123-Toshiba-MIT quick charge batteries and EEStor super capacitors and accellerate mass production of PHEVs.

marcus

I'm with you Harvey.....

Robert Schwartz

The chemical formula of this stuff is C60Li12H60. It has a molecular weight of 864. One Mole contains 60g of H. I found the density of C60 to be 1.65g/cm3. Ref. This stuff is 20% heavier than C60, so lets assume 1.98 g/cm3. 1l of this therefor weighs 1980g and is 2.29 moles of stuff containing 137.5g of H. 1Kg of H contains 120 MJ of energy [Ref] so this stuff has an energy content of 16.5 MJ/L or 8.33 MJ/Kg.

MJ/kg MJ/L
Liquid H 120 8
gasoline 44 29.0
ethanol 22.61 19.59
methanol 22.61 14.57
C60Li12H60 16.5 8.33
Li-ion battery 0.54--0.72 0.9 to 1.9
NiMH Battery 0.22 ?
Pb acid battery 0.11 ?

the real question would be about the amount of energy required to manufacture this stuff (including the amount requried to manufacture H) and the amount required to extract hydrogen from it.

Paul Dietz

C60 is easier to make than carbon nanotubes, with a cost several orders of magnitude lower (dollars per gram). That would still be too expensive for this application, though.

About producing hydrogen: you'd either do it thermochemically from coal, and sequester the CO2, or you'd use some sort of mostly thermal watersplitting cycle, either from a high concentration solar receiver or a high temperature nuclear reactor. There's an interesting cycle in which a transition metal oxide, such as a manganese oxide, is dropped through air as small particles through the focus of a high concentration solar receiver. At very high temperature the oxide partially dissociates to oxygen and a lower oxide. The reduced oxide goes through various reactions that ultimately reoxidize it and also evolve hydrogen gas.

Bob

If we are looking for lightweight tech here is a reall
wild one. Hope this gets funding as it sounds fantastic.

http://www.sciencentral.com/articles/view.php3?article_id=218392647

Andrey

EV theme is not a new one. Every 10 years there is new waive of interest about EV. Look, for example, what was written on CALSTART about 8 years ago. EV concept is very well researched, and there is no need to re-invent things like gasoline range extender or battery swap. They were notoriously researched and declined years ago.

While it is generally thought that the problem with EV is battery, it is actually not. The insurmountable problem is battery charging. At the energy level required to propel EV for acceptable range, it is not even theoretically possible to “fast charge” it. No matter what you hear about fast charge, for EV it is not true (unless somebody will invent high temperature superconductor).

The rise of FC was partially inspired by hope that FCV could be conveniently and fast refueled. Again, the main problem of FCV is not that PEM fuel cell is prohibitory expensive, and even not that hydrogen cycle is terribly inefficient. The real problem is that gaseous fuel, and especially hydrogen, is inconvenient.

Nothing else then convenience of liquid fuel will do, at least to personal transportation market. It could be “charged” electrolyte to EV, or liquid hydrogen carrier (hydrazine-like?) for FCV, but before these technologies will emerge EV, FC, CNG, LNG or alike technologies could hope only for niche applications (some times quite big, like CNG buses).

PHEV with overnight charging from regular household outlet is currently the best real thing we have.

NBK-Boston

Hydrogen has one major strength: Functionally limitless qunatities of it can be stored using fairly simply technologies, if space is not an issue. Hydrogen can be generated from electric sources during off-peak or baseload periods, and stored in simple large tanks. This includes unpredictable "green" sources, such as solar and wind. Moreoever, it can be produced during those moments very efficiently, as high temperature/pressure variants on electrolysis yield good overall thermodynamic efficiency. By contrast, if you wanted to store the electricity directly, in batteries or capacitors, you'd have to spend a heck of a lot more on the storage equipment to be able to pack away the same amount of electricity. One of the biggest issues surrounding green power, now that commercial-grade windmills are reasonably priced, is buffering its inherent unpredictability. Old-fashioned pumped storage is not a bad option, but having a hydrogen option means that your storage capacity is virtually unlimited. Hydrogren begins to make sense when you think about it from the supply side -- it is potentially very easy and green to make; now you have to find something to do with it. Why not put it in cars? To the extent that we try to rush a hydrogen economy into being by burning extra hydrocarbons to synthesize the hydrogen, we're missing the point.

Hydrogen has one minor strength: It can be transferred fairly quickly, so it can travel from one fixed installation to another by pipe as needed, and it can be fed into a vehicle quickly. Current batteries are not nearly as quick, but the prospect of "quick charge" batteries starts to limit the importance of this quality.

The problem is, hydrogen makes a pretty poor automotive fuel. It can burn in an ICE, but not with any more efficiency than other more convenient fuels. It can be put through a fuel cell, but fuel cells cost a lot to make. Storage in a small enough space is a problem, though given enough brainpower, some solution like this one will eventually offer hope.

Hydrogen is not without potential. But given the current state of things, battery-based systems in the EV/HEV/PHEV family seem to offer a lot more environmental bang for the buck, and a lot more quickly, too. Hydrogen might be a good way to buffer green electricity supplies, and reforming NG through a home-size combined heat/electric appliance might improve thermodynamic efficiencies and cut costs. But fuel cells in cars is not the easiest or most sensible road.

NBK-Boston

"No matter what you hear about fast charge, for EV it is not true (unless somebody will invent high temperature superconductor)."

Please explain.

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