• Mar 22nd 2010 at 6:56PM
  • 24
One of the biggest weaknesses of today's battery technologies are their power-to-weight ratio. If you want to go fast or far, you need to carry a lot of heavy batteries with you. But a team of scientists from MIT have made a discovery that could signal the beginning of an entirely new age of energy storage technology. We want to say just one word to you... just one word. Are you listening? Nanotubes.

Nanotubes are hollow carbon tubules about a billionth of a foot in diameter. They're one of the strongest substances on earth and one of the best conductors around. In fact, they can handle an electrical current density about 1000 times greater than copper. Now, the team from MIT says that carbon nanotubes have proven they could hold the key to super-powerful or super-lightweight batteries in the future. They're not the only ones working on nanotube batteries, but they do have a unique approach.

Click past the break to find out more.

[Source: MIT News]
Basically, and we do mean basically, it goes like this: First, the carbon nanotube is coated with a reactive fuel. Then a heat source, either a laser or a high-voltage spark, sets the end of the nanotube ablaze – picture a tiny fuse. The heat from the burning fuel passes into the center of the nanotube where it travels thousands of times faster than it would through the chemical reaction of burning the fuel itself. Through this process, a thermal wave is created that travels along the length of nanotube so fast that it actually pushes electrons out in front of it along the length of the nanotube.

Remember in the movie Mission Impossible when Tom Cruise blows up the helicopter inside the train tunnel and the force of the explosion blasts him safely onto the back of a speeding train? Well, it's like that. Except that instead of a train tunnel, it's a carbon nanotube. And instead of an exploding helicopter piloted by Jean Reno, it's a laser, and instead of Tom Cruise, it's a bunch of electrons.

The point is, when electrons move, you've got electricity. How much electricity is generated by the burning nanotube? The team at MIT theorizes that a carbon nanotube battery could produce as much as 100 times the voltage of an equivalent weight of lithium ion. One-hundred times!

Does this mean the 900 pounds that the Tesla Roadster is carrying in the form of 6831 lithium ion batteries could one day be reduced to nine pounds worth of carbon nanotube batteries? Assuming MIT's number crunching is accurate, it seems feasible. One wonders if a thermo wave battery would suffer from the same cold-weather-electron-reluctance as the battery packs in some electric vehicles have displayed.

But all is not necessarily green with nanotubes. A study from the University of Cambridge shows that carbon nanotubes can enter human cells and accumulate in the cytoplasm, causing cell death. So whatever you do, don't go licking that carbon nanotube battery in your 2025 Nissan Leaf.

For a good read that's not overly techy, click here.

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    • 1 Second Ago
      • 5 Years Ago
      The quoted figures are correct. I've been searching for the original MIT report without success but came upon similar research being conducted from AIST in Japan.


      • 5 Years Ago
      It might prove inconvenient when the battery's thermal wave released the 50kwh or so of energy in a couple of seconds.
        • 5 Years Ago
        You think wicked! :-)
        • 5 Years Ago
        But just think of what you could do with 180 megawatts for a second. Could be pretty useful for an exotic application like a railgun, or maybe a military laser. Or the ultimate drag racer...
      • 5 Years Ago
      Let's put the wars on hold for a year and throw the $150 billion at battery research instead. You can have a lot of smart people working at this 24/7. If it doesn't work, we can go back and defend freedom the following year.
      • 5 Years Ago
      Don't see how this relates well to a car battery. There is a fuel consumed, burned and then it is done, throw away. They do not suggest that a re-chargeable version is in the works.

      What really caught my eye was the statement about carbon nanotubes being able to carry a current 1000 times greater than copper. This is astounding, approaching room temperature superconductors! Think about building the electric motor 10 or 100 times smaller, skinny wires from batteries to controller and on to the motor. Probably even lead to much smaller controller. And carbon is a lot more plentiful than copper, also lighter weight. This means that even though nanotubes are expensive now, eventually they will be cheaper than copper.
        • 5 Years Ago
        Not quite that simple, the electrical resistance isn't less, certainly not a thousand times less. It's just that carbon has a much higher heat resistance than copper does, so it can carry more current without vaporizing. Remember that at one time, carbon was used for incandescent lightbulb filaments, its heat resistance (with no oxygen present) is exceeded only by tungsten and platinum.
      • 5 Years Ago
      Seems like this technology is fundamentally unsuitable for rechargeable batteries. Maybe one time use batteries, but there are too many problems with making something like this rechargeable.

      The nanotubes are coated with a reactive fuel. Being on the nano scale, it seems unlikely that you could "refuel" the nanotubes on the fly, within an automobile, just by pumping fuel into it.

      Also, how damaging is this combustion to the nanotubes? Do they even survive at all to be "refueled"?

      I'm not saying it would be impossible... Just that even 100x the range would not be worth the price of that.
      • 5 Years Ago
      I wish all these wizards would spend less time trying to figure out how to make the batteries better and would instead spend more time trying to figure out how the make the batteries cheaper. See if you can replace some materials with cheaper substitutes. See if you can simplify fabrication steps.
        • 5 Years Ago

        Should the researchers and experts in nanotech at MIT quit their jobs and try to turn recycled bottles into batteries? I think the hundreds of universities and R&D labs in the US and around the globe can do both at the same time....I mean do you think there's only 3 guys in a lab dividing their time up between building higher density batteries and figuring out how to make them cheaper?
        • 5 Years Ago
        Generally the ultimate cost comes down to the amount of material, more efficiency means less material and therefore lower cost.
        You will note that there are usually separate teams of engineers/physicists/chemists working at different levels. GM is working on bringing cost down in packaging, LG Chem in materials, researchers look for new and novel possibilities. All working together toward one common end, cheaper lighter smaller batteries.
        • 5 Years Ago
        Got some lead acids to sell to ya.. ;)

        If you look at computer chips, they are manufacturing them smaller & smaller every year. As they shrink the die even more nanometers, the processor requires less materials, which is good, but a higher production cost.

        The end product is a smaller processor at the same price as the previous one, that performs even better.

        Nanotubes are kinda the same thing. If they end up working in real life as promised, the batteries could have one hell of a bang per buck value. The expensive manufacturing process could be strongly outweighed by the capacity.
        • 5 Years Ago
        Don't beat up on Spec too bad till you think through his argument. In principal I agree with Spec. Take that a step further: we do not need any revolutionary breakthrough in order for electric vehicles to take a large percentage of the auto market. Focusing on process improvements and economies of scale and at the same time creatively using existing technologies can achieve the end result needed.

        Even lead acid batteries can be viable in a medium range EV when coupled with a bank of ultra-capacitors costing less than $3000. The ultracaps would do all the "heavy lifting" of regenerative braking and acceleration, smooth out the load on the lead acid batteries thereby increasing their lifespan (weight and short lifespan are two downsides of lead acid).
      • 5 Years Ago
      Sounds great on paper or in the lap, but this requires combustion which means:
      - You need an air intake & exhaust.
      - You need a fuel delivery mechanism that efficiently distributes fuel to microscopic tubes.
      - You need a microscopic ignition system.
      - You need liquid fuel which is likely derived from oil.
      - If the fuel is not entirely pure you have issues with buildup in the tubes and particulates in the exhaust, and possibly carbon nanotube particulates.

      This is more like a fuel cell than a battery, but even less practical than hydrogen fuel cells.
        • 5 Years Ago
        Yep, news reporters often get it wrong. This is thermal energy converter, not a "battery", and while the power output is substantial, the efficiency is low and energy density isn't so hot (pardon the pun). Worse would be the tendency for the device to slowly self-destruct, as those carbon nanotubes can and do burn if they get hot enough, but lowering the combustion temperature of the fuel would also lower the efficiency - the Carnot rules still apply. This wull more likely be used where a big jolt of power will be needed for a short interval.

        Geronimo, I suspect you've got those figures wrong, 20 to 30 Kwh per Kg isn't physically possible with andy type of capacitors, 20 watthours per Kg would be more likely. Using graphene instead of metal plates would help improve energy density, but capacitors still need insulating materials and graphene is completely useless as an insulator. Now maybe they might achieve 20 to 20 wh per Kg, which would be a big improvement in capacitor technology, but it would merely match lead acid energy density, and be inferior to NiMH and LiIon, and far inferior to advanced batteries under development.
        • 5 Years Ago
        Check up on oxygen doped Graphene. The higher the doped concentration of oygen on graphene the more it tends to become an insulator. Graphene can be modulated with oxygen to act as a semiconductor or with sufficient oxygen as an insulator. Additionally, every variant product is chemically stable.
        • 5 Years Ago
        I don't know if these are the same researchers at MIT that released a press info claiming they had successfully designed nano structured capacitors in the pico - and nano Farad range. The article appeared in the middle of last year. They had raised MWCNTs on bits of Graphene. Finding a viable industrial process for manufacturing capacitors the size of a e. g. standard sheet of paper would allow a design with an energy density of approx. 20 to 30 kWh / kg; but that is definitely not an easy task. But neither should it be impossible until is has been proven as such.
        The advantages would be:
        1) More than sufficient energy density
        2) No problems with power density
        3) Unbeatable efficiency
        3) No leak leak current while idling / storing
        4) No chemical action and subsequent temperature impact
        5) Literally no wear and tear if not abused etc., etc.
        A perfect energy storage device. It would certainly be a pain for any car manufacturer because they want to sell a new battery at least every ten years
        • 5 Years Ago
        You're making a lot of assumptions and a few glaring mistakes. Maybe leave science to the guys that know it?
        • 5 Years Ago
        Some good points Paul but you do make a leap assuming that the thing can even BE recharged/refilled. The article said nothing about that. A careful reading of the article leads me to believe that it's a throwaway power unit with no recharging possible.

        From the article: "each of these electrically and thermally conductive nanotubes was coated with a layer of a reactive fuel that can produce heat by decomposing." Decomposing is the key here - a destructive process, not repeatable or rechargeable, much like burning wood.

        As some others here have, I have put on my skeptic hat with this one. It just looks like researchers churning out yet another in an endless line of studies that will never make it out of the lab.

        /I'll be interested when they produce a workable prototype battery based on the principals. Till then, it's a dead end.
        • 5 Years Ago
        Good questions. They've shown that burning one end of a carbon nanotube sends a high-current pulse to the other end, at most a few millimeters away.

        Nik Bristow, I haven't seen anywhere where "The team at MIT theorizes that a carbon nanotube battery could produce as much as 100 times the voltage of an equivalent weight of lithium ion". The report actually says "the system now puts out energy, in proportion to its weight, about 100 times greater than an equivalent weight of lithium-ion battery. " Well, *BURNING STUFF* tends to do that. A pound of gasoline already "puts out" more energy than a pound of batteries.

        polo, some of us read the original article. The MIT *News* Office's breathless reporting ends with the whimper "Also, the present versions of the system have low efficiency, because a great deal of power is being given off as heat and light." Burning reactive stuff coating one end of a nanotube tends to do that.

        The actual paper that the "guys that know it" wrote doesn't even mention batteries! These days university press offices do a great job of hyping basic research, then bloggers and commenters really get carried away.

        It is a strange novel unexpected phenomenon, but several huge leaps away from being a one-shot battery, and more huge leaps from being a rechargeable battery.
      • 5 Years Ago
      Is it just me or does it seem like researchers make a career out of "researching" things and have no incentive to focus their efforts on solving any real world problems or issues. There seems to be a disincentive for the ivory tower types to ever actually do or make anything. Am I just "not getting it" or are these researchers fleecing us taxpayers?

      /I better take off that skeptic hat now...
        • 5 Years Ago
        I was just lamenting that there seems to be a disconnect between the research and its practical application.
        • 5 Years Ago
        Scientists are still determining fairly basic properties of carbon buckyballs/nanotubes/sheets/whiskers, etc. Large electrical pulses triggered by heat is a great example. Without this sort of basic research there wouldn't be any new areas for applied research.
        • 5 Years Ago
        Is it just me or does it seem like researchers make a career out of "researching

        Yes they do..

        Researchers see if things are possible

        Engineers figure out if you can make something with the research

        Business people figure out if you can make a product out of what the engineers make

        Sales people try to figure out is there a market for the product that business people make

        And the Government Taxes every level

        Its the circle of life

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