back to article Sweet work, fellas: Boffins build high-density battery powered by sugar

Scientists at Virginia Tech have come up with a new battery that uses one of nature's most common forms of energy storage – sugar. sugar battery American innovation in action "Sugar is a perfect energy storage compound in nature. So it's only logical that we try to harness this natural power in an environmentally friendly way …

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So...

...can you eat it when it's expired? Or stick it in your coffee?

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Anonymous Coward

Re: So...

Only if you think coffee is improved by carbon dioxide and water, because that's the result of the reaction which generates the electricity.

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Re: So...

Coffee is definitely improved with some water included.

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Unhappy

Re: So...

"carbon dioxide and water"

Urrrggh! Fizzy coffee!!!

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Help me out here

How do those figures compare to current batteries? Is it low capacity, so interesting but useless, or is this a serious option for future batteries?

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Re: Help me out here

have a look at the linked article..

http://www.nature.com/ncomms/2014/140121/ncomms4026/fig_tab/ncomms4026_F4.html

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Re: Help me out here

0.8mW per cm², a maximum current density of 6mA per cm² and an energy-storage density of 596Ah per kg.

To put this into perspective… I have some 12V (so 6 cell) sealed lead-acid batteries about the size of house bricks weighing in at around 1.5kg. 9Ah capacity, which equates to 6Ah/kg.

We don't know what the mass per cm² is for these new cells, but 596Ah/kg looks quite good.

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Re: Help me out here

Except that calculates the cells as having 0.13V per cell, lead-acids are 2V - more than ten times as much. Should be comparing J/KG, not Ah/KG

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Re: Help me out here

Actually no, that calculates as 130mV per cell, if the cell is 1cm² in area. We don't know how big they're making their cells and what the mass of the cells are.

I'd agree with you on the J/kg measurement, but I'm just working with what's mentioned here as I don't have access to the full document or the remaining information. There are factors we don't know, so it's not an apples-to-apples comparison.

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Full story?

"The only waste products are hydrogen and water, ...."

The hydrogen could be fed into a hydrogen fuel cell I suppose. What happens to all the carbon in the maltodextrin? The linked reference mentions the 'complete oxidation of maltodextrin', hence some carbon dioxide would be formed.

How much energy would be expended in the extraction, isolation and delivery of the maltodextrin feedstock and the preparation of the catalysts? What would be the financial and energy costs of maintaining the battery? etc ....

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Re: Full story?

The referred article says "the complete oxidation of glucose", so there is no way that hydrogen is produced. Complete oxidation means the end products are carbon dioxide and water.

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Re: Full story?

The carbon originally came out of CO2 in the atmosphere, when the sugar beet plants were growing. You are only putting back something that was already there before. This is not at all the same as burning carbon that, as part of coal or oil, has been kept out of the cycle for millennia.

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so the CO2 that is released in the process is not considered a waste ?

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Silver badge

if it doesnt cause any problems...

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Assuming the sugar is of biological origin, it was made in a plant by photosynthesis using atmospheric CO2. So it's a closed loop (assuming the plant is regrown ... a fair assumption for agriculture).

There is a carbon cost, in that agriculture uses fossil fuels for powering machinery and for making Nitrogenous fertilizer.

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lovehandles

im still waiting for something i can stick in my waist, will eat up fat that i have in abundance, and create a induction field that charges my phone when its in my pocket.

gogo gadget!

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Re: lovehandles

There is something you can put on your lovehandles, it is called MRSA, it is quick and efficient, removes fat like you wouldn't believe!

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Fueled by sugar, but fuel is not flammable...

...Are you sure? My hazy memories of chemistry class are assuring me sugars burn like the clappers. Is Maltodextrin an exception?

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Anonymous Coward

Re: Fueled by sugar, but fuel is not flammable...

You're thinking of fats, which do burn well in air (hence "spontaneous" human combustion and that UK local news favourite, the chip pan fire). Sugars tend to melt and carbonise (turn to caramel) and go out. But chemically, sugars are easier to degrade in solution using enzymes.

I want to know if it's more efficient than feeding the maltodextrin to rats and making them run treadmills.

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Re: Fueled by sugar, but fuel is not flammable...

Since the maltodextrin will be in solution then you will first need to dry it before you wish to ignite it.

As a biologist the man problem I can see will be keeping the unit sterile. The environment is full of bacteria, fungi and assorted protists who will happily chow down on maltodextrin. Since the cells would have to be refillable since they are not electrically rechargeable (yet) then that provides an ideal route for infection.

Being unable to use your battery because something ate the charge is going to be a problem. I also wonder what the range of operating temperatures that enzyme has.

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Thumb Up

Re: Fueled by sugar, but fuel is not flammable...

So your battery gets a yeast-infection and starts to ferment its electrolyte. Add a touch of hops and I can see some potential here.

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Re: Fueled by sugar, but fuel is not flammable...

Sugars are quite flammable. In 2008, a sugar plant in Georgia (state) suffered a catastrophic dust explosion that was caused by ignition of the sugar dust in the air. 14 people were killed and 40 injured; the fire burned at around 4,000F (compared to the usual 1,000F to 1,800F a typical building fire sits at).

Maltodextrin is different than surcose (refined sugar), but they both carry the same dust explosion issue. In a battery, where is is unlikely to be in a dust-like state, it won't be explosive and flammability might be limited, especially if in an aqueous solution. Nevertheless, sugars can burn, and burn hot.

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Silver badge

Re: Fueled by sugar, but fuel is not flammable...

Sugars are quite flammable. In 2008, a sugar plant in Georgia (state) suffered a catastrophic dust explosion that was caused by ignition of the sugar dust in the air.

That's stretching the definition of "flammable" in this context past the breaking point. Since, as you note, the batteries are not large spaces with sugar dust drifting about in air, the sugar-plant explosion is in no way comparable. Neither will these batteries regularly be used in, say, an atmosphere of pure oxygen. Flammability is not an absolute attribute; it indicates relative risk of combustion in normal use and plausible failure modes.

Grain elevator explosions are hardly uncommon, but we don't go around complaining that corn is flammable. Steel wool burns nicely in our atmosphere (at normal conditions), but that doesn't lead us to blithely label steel as "flammable".

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Boffin

Energy density

Energy density is measured in Wh/kg.

Proclaiming an energy-storage density of 596 Ah kg−1 is meaningless, because the voltage is missing.

I could claim that our drive battery has an energy density of 10000 Ah/kg simply by lowering the output voltage sufficiently (using a DC/DC converter).

Also, seeing that this is a fuel-cell, not a battery: What does the mass data relate to?

Mass of fuel cell alone? -Then they should compare to other fuel cells, not to Li-Ion.

Mass of fuel cell and fuel? -Then it is easy to fake good results by combining an oversize large fuel tank with a minuscule fuel cell. .. Which, when taken to the extreme, equates to the energy density of the fuel alone.

-Which is also quite misleading. We fly some 500 km on 5 kg of hydrogen. Sounds nice?

Wait until we have added the weight of the fuel cells, the peripheral systems and the pressure vessels.

El Reg is not at fault here though. Whoever wrote that press release either was being willfully misleading or ignorant of the matter at hand.

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Re: Energy density

If you bothered to look at the article on nature.com that is linked, you would see the image I posted above, as well as a PDF with "Supplementary Table S3 Comparison of energy densities of batteries and EFCs", which contains an information about voltage as well - it is 0.5V

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Boffin

Re: Energy density

Thank you..

I looked at the article, but did not see the table.

596 Ah kg−1 at 0.5V yields 298 Wh/kg, which fits to 15% maltodextrin (24 e) found in "Supplementary Table S3 Comparison of energy densities of batteries and EFCs". If I read the table correctly, then this means that the 298 Wh/kg relates to the fuel mixture, not to the complete system.

For comparison

Li. Ion: 180 Wh/kg is a reasonable value for a cell with good power and lifetime values. I know of alternative chemistries that have achieved 300 Wh/kg in lab conditions.

Although I would be happy to see a good and lightweight fuel cell that can use this fuel, I fear that the 298 Wh/kg will be slashed substantially for any application that is not "low power over extreme intervals". Even for such an application, 298 Wh/kg is not "one order of magnitude higher than that of lithium-ion batteries". However, it is also not one order of magnitude less, which means that this is a technology to keep an eye on.

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Bronze badge

Re: Energy density

"El Reg is not at fault here though. Whoever wrote that press release either was being willfully misleading or ignorant of the matter at hand."

Well, I'm afraid they are. What you raise are excellent points that occured to me too, and it doesn't take a great deal of knowledge to note that Ah is not a unit of energy storage. Regurgitating tracts of press release without asking obvious questions is surely closer to churnalism, than journalism.

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Re: Energy density

cm2 seems to be translated incorrectly from "cm" and a "-2" footnote marker. Of course, now it's missing two dimensions instead of one.

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Boing once, boeing twice

I think an el reg unit would be something like "suitcase per passenger per hour" waiting for the bird to fly.

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Get over here and give me some sugar!

My batteries are running low.

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Joke

On the downside

... the batteries tend to lose a fair chunk of charge during your morning coffee.

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Coat

I guess there wouldn't be much of a market for the low calorie or light version as they'd be mostly dead from the get go.

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solar power

Fantastic news,

Uk Sugar beet harvest has another use,

but are the batteries re chargeable, or primary cells,

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Anonymous Coward

Re: solar power

Primary, obviously, since they work by oxidising a reducing agent in a reaction that isn't reversible simply by driving current backwards into the cell. In secondary cells the reaction must be reversible in the same chemistry.

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Silver badge

Rechargable ...

Now that would be worth even more as a food source!

Nuclear fuel (fusion?) Power Station input and synthetic Food out (Sugars)! I don't think a rechargeable one is possible until they figure photosynthesis and then it will only recharge on sunlight, not electricity.

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Silver badge

Boffins build high-density battery powered by sugar

No they haven't. They have demonstrated that a hypothetical energy source can be made to produce electricity.

The day that that process can be found in a battery is decades away if all the previous impressive declarations of these past years are anything to go on.

Not knocking the work in any way - I find what they did quite interesting - just putting things in perspective.

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Pint

Well done!

Let's face it, it's the beginning and on a very limited basis. They've not explored all the potential of this cell. I would hope that down the line they find a way to make it scalable and economically feasible. Just the thinking alone could lead to something even better.

The team deserves a beer for exploring some uncharted territory in research that could benefit us all.

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