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Power Science

Carbon Nanotube Batteries Pack More Punch 163

cremeglace writes "Researchers at MIT have come up with a new way of making batteries from carbon nanotubes. Carbon nanotubes are attractive materials for battery-making because of their high surface area, which can accept more positive ions and potentially last longer than conventional batteries. Instead of this design, the MIT researchers introduced something new — using chemically modified carbon nanotubes as the positive ion source themselves. For now, the new batteries can power only small devices, but if the method can be scaled up, the batteries may provide the power needed for applications like electric cars."
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Carbon Nanotube Batteries Pack More Punch

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  • Battery research (Score:2, Interesting)

    by Walterk ( 124748 )

    In the last year or so there's been a new battery research story every month promising longer lasting batteries that are smaller and usually cheaper. Yet the most advanced you can buy are still just play Lithium Polymer batteries which seem to power my Android phone for about 15 minutes.

    Call me when this research turns into a produced battery.

    • by Hognoxious ( 631665 ) on Monday June 21, 2010 @10:30AM (#32641722) Homepage Journal

      Obviously it's [Aliens|Battery manufacturers|the Taliban] who keep [buying up the patents|assassinating inventors|abducting scientists and anally probing them] in order to [build a new caliphate|prevent humans developing interstellar travel|protect their profits].

      • Actually, a bunch of us don't particularly believe in any conspiracy, but are nevertheless kinda jaded and cynical after hearing one too many (or a few thousand too many) press releases that promise the moon and then some.

        Don't get me wrong. I for one don't propose to cut their funding or anything. It's good that they research stuff. I do wish though the press and PR didn't have the tendency to grandstate.

        • by Avtuunaaja ( 1249076 ) on Monday June 21, 2010 @10:53AM (#32642026)

          Everybody knows that if you can design an economically viable improvement on present-day batteries, you are going to be wildly, obscenely rich. There are plenty of applications where people would be perfectly willing to pay several times more for a battery than what they are paying now if there was a significant improvement in capacity/mass. This leads to a lot of research being concentrated even on very wild potential ideas. Many are viable in the lab, but are too expensive to produce (by a margin of several orders of magnitude), too dangerous, too short-lived, or any combination thereof.

          No matter how many misses there will be, this situation is more or less the ideal case for a free market to optimize for -- if it is possible to safely store more electrical energy in a smaller mass, it will be found eventually.

          • by Myopic ( 18616 )

            Just a minor point: "free markets" are like perfect circles: an interesting thing to think about, but they can't exist in the actual universe. Three cheers for markets, but thoughtful people should stop talking about "free" markets.

            Other than that you make a very good point and state it well.

            • Man way to be myopic about his comment.
            • by lgw ( 121541 )

              I bet you grep Slashdot for the term "free market" just so you can post that. We get it - everyone who has ever looked at economics gets it. When people say "free market" they usually mean "reasonably unregulated market where prices are set by supply and demand withut government sponsorship or price intervention". "Free market" is less of a mouthful.

              Sure, you get the occasional Randroid or big-L Liberartian on /. from time to time, but even here you can usually assume that when people say "feee market" t

              • by Myopic ( 18616 )

                Not only Slashdot! I take the opportunity whenever I can, because I think it's important. Most people use the words "free market" to mean "market", and I think it's dangerous to confuse the two. "Free market" ideologues are dangerous and push an agenda which harms people. When people to casually toss around support for "free markets" when they don't really mean it, they unwittingly give credence to some very dangerous policy pushers.

                And I guess my point is that people don't "get it". If they did, they would

        • by phantomfive ( 622387 ) on Monday June 21, 2010 @02:48PM (#32645120) Journal
          The problem is your source of information. Press releases aren't a very good source. If it's something you care about, look deeper like in a journal or something.
    • Agreed. And while we're at it, are there ANY nanotube products on the market yet?
    • by Khyber ( 864651 )

      I guess you've not heard that we fixed the whiskering issue with nickel/zinc batteries. I've been using them in my devices and they're better than Lithium Polymer, NiMh, or NiCd.

      Love that 1.8 peak and 1.6 nominal voltage, with a bit over the typical capacity of Ni-MH.

      If only they made AAA versions.

    • Lithium Polymer batteries which seem to power my Android phone for about 15 minutes. Call me when this research turns into a produced battery.

      Since you won't get the call, you'll just need to keep watching the skies for our flying cars. The cells will be filled by fusion power, of course.

    • by CAIMLAS ( 41445 )

      15 minutes? You must be using the wrong batteries, or something. That's horrible runtime.

      You can easily find single-cell Lithium rechargeables (18650 cells) with 3200Mah ratings which deliver 3V. They're not cheap, but they're not that hard to find, either.

      I'm not saying li-ions are awesome, but you're kind of understating things a bit, eh?

      • by erayd ( 1131355 ) *
        A 3V 18650 cell would be a very flat cell! Nominal voltage for an 18650 LiIon is 3.7V, with a maximum of 4.2V.
        • At 3200 mega-are hours (or 32 million square kilometer hours) that battery could supply one fifth of the total land area of the Earth with 3 volts for one hour, though. That's pretty powerful.
    • by jeffmeden ( 135043 ) on Monday June 21, 2010 @11:44AM (#32642808) Homepage Journal

      In the last year or so there's been a new battery research story every month promising longer lasting batteries that are smaller and usually cheaper. Yet the most advanced you can buy are still just play Lithium Polymer batteries which seem to power my Android phone for about 15 minutes.

      How weird. The tiny lithium battery I put in my smartphone a year ago still powers it for at least a day's worth of use on a full charge, if not more depending on how little browsing and video watching I do. I won't spoil the ending and tell you what kind of phone I have; I will leave that as an exercise for the reader.

      And for what it's worth, it may feel like an eternity but no less than 10 years ago we had no such fancy-fangled inexpensive lithium batteries for our phones/laptops. If you wanted one, it was gonna cost you, it wasn't going to hold much energy, and it would be dead with about 6 months of regular use. Today's very cheap, highly durable, very energetic lithium polymer batteries are the result of continuous un-sexy research that made headlines in the 80s and 90s, but is still undergoing a lot of change and improvement. The next revolution in battery storage will probably also happen without much fanfare; I hope your phone holds out until then!

    • by Rei ( 128717 )

      In the last year or so there's been a new battery research story every month promising longer lasting batteries that are smaller and usually cheaper. Yet the most advanced you can buy are still just play Lithium Polymer batteries which seem to power my Android phone for about 15 minutes.

      The late '80s just called -- they want you to remember what their cell phone batteries [wordpress.com] looked like.

      The problem is that batteries aren't advancing. They are, at about 8% per year. It's that electronics manufacturers aren't

  • by jeffmeden ( 135043 ) on Monday June 21, 2010 @10:13AM (#32641458) Homepage Journal

    Will they be able to prevent thermal runaway in these better than in, say Lithium based batteries? As density goes up this needs to be more of a concern. Laptops melting down are one thing, but imagine the havoc of a car exploding due to battery failure. That's the last thing the electric car movement needs to have happen.

    • by IflyRC ( 956454 ) on Monday June 21, 2010 @10:45AM (#32641926)
      I fly a lot of R/C models ranging from turbines to electric powered helicopters. The chemistry in the batteries has changed over the years but the highest output batteries right now are lithium polymer. Now, there are some A123 type batteries that are better and getting better but most of the extremely high powered aircraft right now use Li-Po. Battery failures can be caused by several things but what alarms me about putting something like this in a vehicle is the hazard of fire in the even of an automobile accident. When you have a high impact with some of these batteries and a cell is ruptured - the packs begin to puff - then vent. When they vent, the heat is thousands of degrees which will set off other cells in the pack. Think of the old stories about exploding gas tanks in the event of a car crash. Now think of all of these batteries packed into tight places under trunks and back seats and getting rear-ended or even just a cell going bad...or the balancer in the charger going out and overcharging a cell causing failure in that cell. A failed charger can cost you your entire car...or better yet, your house. Think of this thing going up in the garage...and you having a gas water heater installed out there. This stuff is dangerous enough as it is right now.
      • by neolith ( 110650 )

        Indeed. And when lipos go, they don't just go up in flames, or at least the ones in RC models don't. They produce an intense, almost blowtorch like flame that can cut through, melt, and ignite materials instantly. See the following video for an example of a 4000mah battery. That would be sufficient to power a 1/8th scale car for 10 minutes or so, or a 1-2lb stunt plane for a similar time. Now imagine something sized big enough to power a car.

        There are containment devices sold that effectively (basicall

    • by CAIMLAS ( 41445 ) on Monday June 21, 2010 @11:05AM (#32642232)

      IIRC, thermal runaway, as you call it, is a problem specific to Lithium based batteries due to the chemical properties of lithium. It's somewhat volatile, you could say: impact and temperature extremes tend to do bad things to it (whether we're talking explody-boom or cell lifetime). Carbon, on the other hand, is innately stable.

      Lithium powered hybrids are just a Bad Idea. I have no idea how they got that shit off the ground.

      • by jeffmeden ( 135043 ) on Monday June 21, 2010 @11:33AM (#32642654) Homepage Journal

        But, "uh oh", these batteries still use Lithium! They simply have a new way of producing the electrode: "The result was a highly porous carbon nanotube electrode with lots of oxygens exposed on the surface, ready to bind with lithium."

        Also, there is nothing inherently tragic about Lithium; any technology that stores and releases energy can fall prey to thermal runaway. In the highly-available-power world in which I work, we have seen lead acid batteries go into thermal runaway after particular amounts of abuse (or defective manufacturing/installation).

        As someone who has used/abused lithium polymer batteries in the RC world (similar to the other respondent) I have seen what can easily happen to high-energy batteries when they are improperly maintained. The question is, what happens when there are hundreds of millions of these packs in cars all across the US, being put through various amounts of abuse? They will fail, and we need a safety mechanism that is highly reliable (like a re-enforced steel shell that can vent hot gases away).

        The comparison to a gas tank is somewhat inadequate as these batteries are far heavier than gasoline; if you have a serious accident that compromises the frame of the car you really can't guarantee that the battery container is going to be unperturbed. There needs to be two or more dedicated safety measures to contain or divert the energy from the batteries away from the occupants in the event of damage.

        • Re: (Score:3, Insightful)

          by BlueParrot ( 965239 )

          any technology that stores and releases energy can fall prey to thermal runaway.

          I'm so sick of this. Lithium-based battery technologies have a high energy/weight ratio because lithium is a very light metal. It has little to do with the fact that the spinel used for one of the electrodes is easily ignited. NiMH batteries are far safer and won't burn or explode the way lithium does, but because the metals used in them have higher atomic masses, they are also heavier for the same amount of energy.

          People keep t

        • The comparison to a gas tank is somewhat inadequate as these batteries are far heavier than gasoline; if you have a serious accident that compromises the frame of the car you really can't guarantee that the battery container is going to be unperturbed.

          Here's a thought experiment for you:
          You want to make an electric skate board. You want to run it using 50 D-cell batteries. How will you arrange them?
          a) Stack them on top of each other at the back?
          b) Stack them on top of each other at the front?
          c) Like a, but

        • The comparison to a gas tank is somewhat inadequate as these batteries are far heavier than gasoline; if you have a serious accident that compromises the frame of the car you really can't guarantee that the battery container is going to be unperturbed. There needs to be two or more dedicated safety measures to contain or divert the energy from the batteries away from the occupants in the event of damage.

          Also: They can release their energy much more quickly (and thus more hotly) than gasoline. Gasoline req

          • by hitmark ( 640295 )

            there have been some recent work on using air as one part of the lithium batteries. Seems it both improves capacity and weight.
            https://secure.wikimedia.org/wikipedia/en/wiki/Lithium_air_battery [wikimedia.org]

          • by hawkfish ( 8978 )

            The comparison to a gas tank is somewhat inadequate as these batteries are far heavier than gasoline; if you have a serious accident that compromises the frame of the car you really can't guarantee that the battery container is going to be unperturbed. There needs to be two or more dedicated safety measures to contain or divert the energy from the batteries away from the occupants in the event of damage.

            Also: They can release their energy much more quickly (and thus more hotly) than gasoline. Gasoline requires oxygen from the air (or wherever) to burn and this limits its thermal power. Lithium cells are self-contained and have all the pieces of the reaction ready to go. (That's why they're heavier than an equivalent amount of gas.) They're only limited by the physics of the propagation of the catastrophic energy release mechanism.

            Could one design a battery that needs oxygen to work? The design in the article seems to embed the oxygen in the nano-tubes, but maybe a different battery design that required airflow to generate power would be safer.

            Have I just described a fuel cell?

      • Re: (Score:2, Interesting)

        When it comes down to it, it's simply energy density... The more you have stored in a finite space, the more potential for release there is and the greater that release could be...

        I'm not saying its impossible to create something stable, all im saying is that certain conditions can have dramatic effects...

        The amount of energy easily released by a tank of petrol (gas, whatever) is massive, but safety precautions that are taken now are fantastic compared to earlier days...

        I'm sure there's a way to keep tha
        • I think there's a bit more to it, and one major physical hurdle to bypass. Gasoline, as a liquid by itself, is fairly harmless. When subjected to the functions of a car engine and combusted, its very dangerous. However, not much gasoline is ever in a place where it can combust into a huge fireball at one time (tank vs. engine). How is one going to accomplish this with batteries, which are by and large solids requiring close contact? Unless you can guarantee 100% that the massive casing for the battery

      • by Rei ( 128717 )

        Wrong. They're specific to *cobalt cathode* li-ion cells. Not any cells that have lithium in them. There are freaking rocket boosters made out of lithium-aluminum, exposed to high temperature flames, and they don't burn. Just because something contains lithium doesn't make it flammable. Just like how because our bodies contain sodium doesn't mean that we explode when we get hit by water.

        The only companies pursuing li-ion cells with cobalt cathodes are Tesla Motors and their partners. The others are al

      • by hitmark ( 640295 )

        well the carbon nanotube "batteries" are more like capacitors then ordinary batteries.

        And capacitors make for fine firecrackers when shorted...

    • by Spoke ( 6112 )

      Will they be able to prevent thermal runaway in these better than in, say Lithium based batteries?

      Unsure - they didn't make any references to thermal stability in the article. Now, since they are talking about improvements to the negative electrode material and not the positive electrode, it's possible it may not have any significant affect on the safety of the battery the technology is applied to since the relative safety is highly dependent on the rest of the cell chemistry.

      The safety of existing lithium

  • Of all the technologies that are supposedly "just around the corner": fusion power, flexible displays, etc., dramatically improved batteries are probably the most wearyingly repetitive. Literally every 3 months since 2005 I've seen an article on Engadget, or wherever, about some university that claims 500% longer-lasting batteries in the lab, to be available to consumers "in 18 months". Ain't happened yet. Let's all claim success about boosting battery capacity when we can actually buy them, until then this
    • if the method can be scaled up, the batteries may provide the power needed for applications like electric cars

      Currently nothing to see here.

      • by John Hasler ( 414242 ) on Monday June 21, 2010 @10:41AM (#32641884) Homepage

        > Currently nothing to see here.

        Yes, because none of us have any interest at all in developing technology. We just want to see the results on the market. Ongoing research? How boring. Wake me up when you can make my 'Pod run longer. Don't waste my time with this stupid "science" crap. That's for nerds.

        • Re: (Score:3, Interesting)

          by Hurricane78 ( 562437 )

          iPod? Sorry, we only work on curing baldness, and making erections work longer.

          (As there is no way to link to it, I’m including the quote here. Just imagine I would have linked to it ;)
          “The years passed, mankind became stupider at a frightening rate. Some had high hopes the genetic engineering would correct this trend in evolution, but sadly the greatest minds and resources were focused on conquering hair loss and prolonging erections.”
          — Narrator
          Idiocracy (2006)

    • by Cyberax ( 705495 ) on Monday June 21, 2010 @10:42AM (#32641892)

      It's working. Battery capacity is increasing, albeit slowly.

      It doubles every 5-7 years.

    • by radtea ( 464814 ) on Monday June 21, 2010 @11:02AM (#32642180)

      dramatically improved batteries are probably the most wearyingly repetitive

      My vote is solar cells, which have had so many breakthroughs that will double their efficiency in the past few years that they must be converting 500% of the light that strikes them by now...

    • by Yvanhoe ( 564877 )
      I read slashdot to also have prospective news. Granted, half of them are hogwash and that is for them that the comments system is so precious, but I don't want Slashdot to just give me news about released products, I want info about what's in the lab as well ! Sure, it means you'll get a lot of vaporware, but that is news for nerds also. I'm a bit tired of the nanotube batteries thing, there must have been 5 or so articles on that already and I just can't force myself to get excited anymore. But I prefer to
    • Re: (Score:3, Interesting)

      by Rei ( 128717 )

      What articles were you reading that said a battery tech would go from "in the lab" to "on the market" in 18 months? 5 years or so is more typical. And 500% battery improvement tech announcements are rare. There are a couple out there, like li-air, but not many. And many people confuse significant improvements on one part of a battery (say, the anode or cathode) with improvements on the cell as a whole.

      Li-ion batteries have advanced about 40% since 2005.

      There's a serious problem with the announcements ma

    • ... all the technologies that are supposedly "just around the corner" ... Ain't happened yet.

      Part of the problem is the ongoing storm of breakthroughs. Not only do they have to turn out to be practical in a real, manufacturable product, they have to remain the cutting edge long enough to make back the cost of tooling up once they come to market. Lots of this stuff gets displaced within months by something better.

      Fortunately enough of the breakthroughs meet this criterion and make it into production for th

  • Something about carbon-based tubers the other day?
  • Always a Catch.... (Score:5, Insightful)

    by BJ_Covert_Action ( 1499847 ) on Monday June 21, 2010 @10:20AM (#32641562) Homepage Journal

    ...but if the method can be scaled up, the batteries may provide the power needed for applications like electric cars.

    And it's that one big damn, 'if,' that actually prevents most technologies like this from seeing commercial production/practical application.

  • I call BS (Score:5, Funny)

    by Tekfactory ( 937086 ) on Monday June 21, 2010 @10:20AM (#32641572) Homepage

    Extra power packed into batteries by a Scientist named Shoe Horn!

  • Yet another new threat of new battery technology that may reach us some day. Been hearing this for so long that I've come to believe that the batteries we have today is all that will ever be.
    • Re: (Score:3, Interesting)

      by cacba ( 1831766 )
      You may try to apply moore's law to things other than cpus, but that doesnt make it happen. The frequency of the news articles shows only a huge demand by consumers and researches need for funding.
  • by BlueParrot ( 965239 ) on Monday June 21, 2010 @11:07AM (#32642270)

    There's plenty of battery technologies that perform well enough for cars already.
    Lithium Iron Phosphate is almost ideal as an example. It holds less charge than a
    Li-Ion pack, but in return it can recharge in a sensible amount of time ( 10-15min ).

    Now I know some people with no clue will come claim that amount of energy can't safely
    be transferred or something. You're wrong. Recharging a 25kWh battery pack (corresponding
    to ~150km of driving) in 15 minutes would require 100kW. This is a bit more power than
    most devices, but heck, my hairdryer does 2kw out of a standard socket, and I'm pointing
    that thing in my face every morning. 100kW might be a lot compared to a cellphone charger,
    and it will take a bit of engineering to design a connector, but it's hardly an unachievable
    amount of power.

    The problem is that these advanced batteries are expensive. Heck even Li-ion is prohibitive
    for a family car. Tesla gets away with it because they are selling a luxury model, but if
    batteries are going to power a significant fraction of cars then their cost has to come down.

    The question now is not so much if but when batteries will take over. Much will depend on what happens
    with the oil and electricity prices, but eventually petroleum will become sufficiently expensive that
    an electric car is simply a more economical choice.

    • Re: (Score:2, Interesting)

      by Anonymous Coward

      The problem is getting 100kW to your house, about 417 amps at 240V. The NEC standard for a single-family home is 100 amps, but most are only rated for about 60. The power pole transformers are usually well provisioned, which means that entire neighborhoods would need to be upgraded to increase everyone's capacity. It is a bigger problem than upgrading phone lines from copper to fiber.

      • Leaving all other problems aside: if the batteries recharge as fast as the GP says (10-15 minutes), it's not inconceivable to charge them at "gas" stations while the residential power infrastructure is being upgraded.

        • You could also charge a second battery in your garage and then simply recharge the first using the second one. Of course that would make it even more important that the price comes down.
      • Re: (Score:3, Insightful)

        by Spy Hunter ( 317220 )

        You don't need a fast charger at your house; overnight charging will work great using cheaper non-peak power, and will probably extend your battery life vs. fast charging all the time. Fast charge stations can be spaced as sparsely as gas stations.

      • most houses these days have at least a 200AMP service coming in.

        I know my apartment that was built in the 20's and doesn't even have plugs with a real ground wire has a 100amp service coming in, and thats 100amps per side of the duplex. (were talking fuse box baby!)

    • There's plenty of battery technologies that perform well enough for cars already.... Recharging a 25kWh battery pack (corresponding to ~150km of driving)...

      Indeed. The biggest problem, I think, will be convincing the American public (in particular) that they can no longer afford a single vehicle that provides both their routine transportation needs as well as the infrequent extreme uses. A small light-weight vehicle that gets most people to work and home, or makes the swing to the grocery plus other local

    • The real cost is (as you said) batteries. Even the cheapest lifepo4/nimh batteries on the market would cost $10,000 in this scenario. Fast charging (I.E. less than 15 minutes) is a non-starter. Where are you going to find that 100 kW outlet? The problem is a chicken and egg problem. In order to have cars, you have to build all these chargers. But who wants to build chargers until there are cars? A much easier solution to this problem can be found here [google.com].
  • by sirwired ( 27582 ) on Monday June 21, 2010 @11:07AM (#32642272)

    Unlike the fuel cell guys, which are constantly promising consumer products shipping in "just a few months", I'm glad these folks realize their work is still well away from widespread application where it's really needed.

    • Unlike the fuel cell guys, which are constantly promising consumer products shipping in "just a few months", ...

      Huh? They're shipping NOW - in power-an-office-building sizes.

      There's no inherent reason they can't be scaled down to power-a-laptop-off-a-butane-tank size in reasonably short order (assuming you don't mind your laptop putting out several times the heat it does now...).

      • by sirwired ( 27582 )

        I was actually referring to those "power a laptop off of butane" guys, who have indeed been promising shipping product for many years, yet consistently fail to deliver.

  • Electric cars face severe limits in how far they can drive before running out of juice. Better batteries that can both store more energy and give it up quickly [...] Detailed tests showed the new batteries hold five times as much energy as conventional quick-discharging devices called capacitors do, and they deliver that power 10 times as quickly as conventional lithium ion batteries can

    So, less energy than lithium ion?

    Useless - utterly useless - for "electric cars". Or indeed anything that currently wor

    • Re: (Score:3, Interesting)

      by drinkypoo ( 153816 )

      In most designs regenerative braking has to throw away power because you can't charge the packs fast enough. A battery that CHARGES faster would be useful not only for quick-charging but also for regenerative braking. I didn't RTFA though so I have no idea if it carries more current in both directions.

      • In most designs regenerative braking has to throw away power because you can't charge the packs fast enough. A battery that CHARGES faster would be useful not only for quick-charging but also for regenerative braking.

        You don't need the full capacity to be of the fast-charge type though, it would be enough to have a smaller "buffer" battery to store energy from braking. The main pack could be topped up by the buffer pack at a slower rate, or the energy could be used directly from the buffer if braking is followed soon after by acceleration (which would often be the case).

        • The main pack could be topped up by the buffer pack at a slower rate, or the energy could be used directly from the buffer if braking is followed soon after by acceleration (which would often be the case).

          It doesn't make sense to use a battery here. But it also doesn't make sense to charge pack to pack, because battery charging is lossy. And of course you want the whole pack to fast-charge, so that you can hook up a super-fat connector and charge in a timely fashion. Gas stations might [very eventually] be replaced with parking lots full of chargers, with some spaces equipped only with fast chargers.

  • Wow! (Score:2, Funny)

    by Rytr23 ( 704409 )
    Is there no end to the usefulness of these 'carbon nanotubes'? And, umm...how many decades before we actually see something commercially viable that uses them?
  • by GodfatherofSoul ( 174979 ) on Monday June 21, 2010 @12:10PM (#32643142)

    ...you know, all the revolutionary achievements we read here every week...and our energy problems are solved!

  • the MIT team achieved its best results with very thin electrodes. The performance dropped off considerably as the electrodes were made thicker. Because thicker electrodes can store more charges, they allow a battery to hold more energy. So for now, hybrid batteries will be best suited to applications with low overall power demands, such as powering electronic circuitry in smart cards, credit cards with electronic chips that hold more information than magnetic strips do. For the batteries to be useful in hyb

    • Coating the body is probably not the best idea (sorry). It will cost a lot in terms of manufacturing to put battery coating all through out the body. The problem with spray paint is that most of this lithium stuff requires really really high purity. You'll have crud (like water) diffuse through the paint and clog em' up.

      The way people make high surface area batteries right now is by rolling em' up. You take two foils (~ the thickness of aluminium foil), paper, and roll it up. Then you get very high surfa
      • If the problem with spraypainting the inside of the car body panels with a lithium/nanotube battery layer is that water would get into the layer, then it seems to me the layer can be sealed. I don't think these are lithium/air batteries that need to be porous. A watertight coating layer, or perhaps a hydrophobic layer that doesn't interfere with the electronic chemistry - or both - seems possible.

        4-5 miles range per day does translate into useful power, like for accessories as you say. It might be useful as

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