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

24 July 2006

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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July 24, 2006 in Hydrogen, Nanotech, Vehicle Systems | Permalink | Comments (41) | TrackBack (0)

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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?


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?

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.

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%

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.

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.

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.

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.

I'm with you Harvey.....

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.

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.

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

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.

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.

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

Please explain.

Andrey - "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)."

Not having invented high temp superconductors A123 has invented nanoscale electrodes that will enable lithium batteries to charge really quickly - about 5 mins.
http://www.a123systems.com/html/home.html

BTW it is not a given that H2 refuelling is quick. Compressed H2 in 10 000 psi tanks could take quite a long time to refill unless the compressor is huge. Liquid hydrogen will be really tricky to refuel. Imagine a leak and something shattering from exposure to -270° hydrogen leaking on it.

Reading the details this has a long way to go before it is practical.

Amminex already has 110 gram/liter and 9.1% weight density using a chemical storage technique. (exceeeding US DOE goal)

http://www.amminex.com/index_files/Page344.htm

BTW there is a good summary of current Hydrogen storage systems at

www.rpi.edu/~goodwc/HydrogenStorage.ppt

NBK:

We are entering the discussion of intrivial technological and philosophical level on your questions here.

Historically humankind moved during its recent technological evolution (more appropriate “revolution” during last 1.5 centuries) to the energy sources/carriers of ever elevating energy density. I mean wood to coal to oil pattern, and also mechanical power to electricity, or steam engine to IC engine to jet turbine pattern. From this point of view conversion to hydrogen gas would be huge step backward counting it low volume/energy density. As any broad and supposedly universal statement, it is more likely reflects our primitive mind and desire to oversimplify nature and human civilization complexity to the sake of impressing the listeners. This argument was used by proponent of proliferation of nuclear fuels, to the extend when highly regarded engineering institution in my home town seriously pursued design of nuclear-powered airplane. Nevertheless, if you suppress the natural to any critical mind attempt to argue it, you probably will agree with it.

Now, as any general philosophical statement, it should realize itself in practical terms. Here they are. Hydrogen gas, as being constituted from smallest in universe atoms, have terrible quality to penetrate through any gasket, seal, or even imbed itself into metal’s surface, making, for example, steel brittle. There is no way to accumulate any significant amount of compressed hydrogen gas because no big vessel would be strong enough to handle sufficiently high to energy storing purposes pressure (same scale effect which prohibit elephant to jump and cow to fly). All means to concentrate hydrogen carry terrible energy wasting disadvantages. Some technologies, however, promise reasonable advantages to hydrogen energy storage – but only on distributed energy level, such as advanced photovoltaic panels.

We already have way more cheap, energy efficient, and convenient means to accumulate energy then hydrogen option. We already have way more energy dense and convenient to handle energy carriers for transportation. I believe that way more appealing from the respective of cost/efficiency options are offered by further development of liquid hydrocarbon energy carriers such as algae biodiesel or mentioned above advanced photovoltaic artificial fuels. To my humble opinion, hydrogen is the fuel of the “future”. And always will be.

Now on fast charge. Current rechargeable batteries (Ni-Mh or to higher degree Li-based batteries) store enormous amount of energy. Converted with 100% efficiency to kinetic energy, these batteries could propel themselves to the speed exceeding of handgun bullet. In order to propel EV for couple of hundred km, buttery of such vehicle should accumulate huge amount of energy, enough to supply high energy output for hours. How you suppose to recharge it fast? In minutes? Use mega Volt conductor? Or wires of human hand diameter? What about switches, contact surfaces, managing circuitry? Do you have any idea how such kind of current/tension are handled on power stations? Do you know that switches are blown by argon gas in order to eliminate electric arc during disconnection?

Generally it is not the biggest problem. The biggest problem is capability of battery to receive such kind of current itself. Any battery has cross-dependent self-discharge, efficiency, internal resistance, thermal dissipation, and run-out limitations. Simply put, any battery has limitation on max power output, defined not only by speed of chemical reaction, but mostly by heat dissipation limit; heat being produced by internal current due to Ohm law of E=I^2*R. As a rule of thumb, battery could not receive any more current that it is capable to produce. That means best recharge time for best current Li-ion batteries is about an hour. Advance butteries probably will double their energy density and double their power density. That means they still will need an hour to be recharged.

Current issue of advanced Li-ion 18650 Li-ion batteries from Sanyo have two modifications. One is high energy, for use with electronic devices, with capacity of 2.7 Amp*h. Another one, with high power capability, for use in power tools applications (and supposedly in EV/HEV) has only 1.2 Amp*h capacity. This is the price to have high discharge/charge capacity. Super/ultra capacitors do have ability to be charged fast. But this is only because they have 100 times less energy density then batteries. You can not cheat Huygens principle.

Ender:
Without any insult in mind to MIT A123 batteries (which are huge achievement), I still skeptical about their fast charge capabilities. For my 20 years monitoring of advances in battery technology, I am historically inclined to divide their claims in 5. I hope I am being wrong on this.

I used to work a little bit with high-pressure gases, and liquid nitrogen (the “mild” one compared to liquid oxygen and hydrogen) too. My everlasting impression of it is that it is highly unpredictable and dangerous s**t.

Re the fast charge idea - it is not as bad as you make it sound Andrey.

A123 and Altair and Toshiba etc can all manage 5 minute recharge with about 100 Wh/kg energy density and very very low internal resistance (and hence heat losses), so the issue is not with the batteries but with the charger.

50 kW and 60 kW EV chargers have been around for ages now, and they look fairly practical to me (see picture below):

http://www.zefiro.com/ev/50kw1.jpg

So park your EV next to two of these (or one larger combined one), and enjoy a 120 kW charge rate. Assuming 5 miles per kWh for an efficient EV, that equates to a 100 mile range for every 10 minutes of charging. That's spot on for the amount of time people would be willing to spend charging a PHEV-100.

P.S. Ender: I probably did not express myself clearly on “liquid hydrogen carrier”. In any means I did not mean liquid hydrogen as convenient trans. fuel. I thought of some kind of liquid-state in normal conditions hydrogen carrying media. Like hydrazine, which is H2-N-N-H2 liquid. On reaction in fuel cell it could (my fantasy) discharge hydrogen and resulted nitrogen could be vented to atmosphere. Too bad hydrazine is fuming toxic chemical with high explosion hazard…

Andrey - you are very sensible to run a million kilometers from hydrazine - it is extremely toxic.

I to do not expect a practical A123 battery pack to be fully charged in 5 mins however I would expect a 'get home' charge of perhaps 20% in this time which would be acceptable. The high rate charge would only be used rarely.

A more likely scenrio is on a long drive, given a range of 400km, is to drive for 350km or so and then stop which you do now in your IC car. Normally you have a bite to eat and a coffee taking half an hour or so in which time your battery has recharged ready to go. You have also recharged and this could enforce safe touring habits of regular stops.

As I said in a previous post the time where anyone can hop in a car and drive 1000km on a whim is getting very close to coming to an end. This convenience has been bought at a price which we will pay sooner or later.

There are simply too many vehicles going too many places at unacceptably long distances. This sad truth is even truer given China's plans to base much of their future on the automobile.

EV or/and PHEV will eventually be implemented on a massive scale. If this is done in a way that maximizes the amount of carbon free electricity used to recharge these vehicles, then it may be feasible to extend the life of the automobile without further massive disruptions to the climate system. In the mean time, further development and/or renewal of cities should be done in a way that minimizes the need for the automobile.

While we debate the perfect alternative to the petroleum fueled ICE, temperatutes continue to soar.

I wonder why don't they try to come up with some standards so that you don't need to recharge the batteries but to replace them. That is, when you keep the car at home, overnight, you recharge the battery, when you're on the highway you go and replace the battery system at a "re-fuelling" sttaion ...

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