back to article Paper batteries on the cards to power IoT and smart labels

Scientists in Switzerland have developed a battery made out of paper which will release its charge when splattered with water. The developers claim it could be a novel solution to power disposable electronics such as smart labels for tracking objects, environmental sensors and medical diagnostic devices. Water activated …

  1. Snowy Silver badge

    Volts is not power

    Would be good if instead of saying 1.2 V you quoted all the information.

    Once activated, a single cell provides an open circuit potential of 1.2 V and a peak power density of 150 µW/cm2 at 0.5 mA.


    We developed a water-activated paper battery for single-use electronics with low environmental impact.

    Life cycle assessment will also be completed to evaluate and compare the environmental impact (CO2/kWh) of our paper battery.

    They can hardly say it has "low environmental impact" if they have not do done an environmental impact study!!

    Paper as a surprisingly large environmental footprint and I'm not sure how well what is left after it as been used is recyclable.

    1. Mike 137 Silver badge

      Re: Volts is not power

      "We developed a water-activated paper battery for single-use electronics with low environmental impact."

      Actually it's not a 'paper battery' - it's a zinc carbon cell with a paper dielectric and they've been around for over a century.. The only interesting bit is that it's printed - which is actually very interesting, as it opens the door both to cheap manufacture and to all sorts of novel geometries.

      1. Anonymous Coward
        Anonymous Coward

        A plus to both of you, solid points

        On the first note, at least the cell would break down rapidly in most environments, and while zinc isn't GREAT as far as residual metals are concerned, it's not like cobalt, chromium, or mercury in that regard.

        As to the impact study, glad they are not overselling it before they have done more then the back of the napkin math, but based on it's construction their claims don't seem to be out of the realm of reason.

        That said, all such lab experiments tend to be years from commercialization, and as something that has novel packaging requirements and will be unfamiliar to customers I expect this will be replacing potatoes in the school science lab before button cells in land fill junk.

        On the second post, it will be interesting to see how the cell geometries impact the performances, as well as layers. In either case though, I think we as a world wide population need to lean into reducing single use stuff where we can, and it makes any kind of sense.

      2. John Brown (no body) Silver badge

        Re: Volts is not power

        Yeah, basically, they've improved/invented/discovered a new application for what most of us will have seen as a high school physics demo/experiment. I don't mean that to denigrate what they have done. They've potentially come up with something useful, but not actually invented a new technology. Good on them for thinking outside the box.

        But I do have a slight snit with the article where it reads "the lead wires". I'm assuming they meant "the wire leads" and not that the wires are made of lead. Just badly worded IMHO since we are discussing electrochemical reactions and lead/acid batteries are a thing too so being precise with words which are spelled the same and could be confused is important. Is it "leed" or "led" :-)

        1. JBowler

          Re: Volts is not power

          >"the lead wires"

          That's "lead" as in "to lead a horse". The term "lead wire" is used to describe connections of this sort; frequently power leads.

  2. Tom 7

    So a ream of a4 can bang out nearly 10 watts.

    And would take a while longer to dry out.

    This will piss kindle off! You can buy a book, hook up a small LED and sit in the bath in the dark reading by steam driven book!

    1. gotes

      Re: So a ream of a4 can bang out nearly 10 watts.

      You could turn a paperback novel into a battery to run the Kindle...

  3. MachDiamond Silver badge

    Using measurements incorrectly.

    >Users can get another hour at 0.5 volts by adding a couple more drops of water.<

    This makes no sense. It's possible to get voltage all sorts of ways that will read on a meter but provide so little power that the device is useless.

    What's the application for this? What happens in a high humidity environment, will it self-activate and die if it isn't sealed in a waterproof cover? How much material and energy to make that material will have to be used if the device has to be sealed prior to use?

    I can get power using the smelly much from a lake bottom (the more ducks the better it works). The downside of the mud battery is it doesn't provide enough power for much but can be scaled up enough to run an efficient data acquisition sensor. I worked on one with a NASA group some years ago and the information can be found online if you want a pretty cool school project that's simple and safe enough for even young kids.

  4. Mayday


    I can think of sooo many uses in the medical field alone. I’m thinking of probes, sensors etc that need to be tossed out once after they’ve been used. Much better than some battery that’s polluting and going to the tip.

    1. Anonymous Coward
      Anonymous Coward

      Re: Magnificent.

      "Printed onto the paper are three inks... ... more environmentally friendly..."

      Be friendlier... aim for 6 inks.

      Although, if you printed your taxes on this and the agent wetted them... dream of fire

  5. Ian Johnston Silver badge

    So, less battery waste ... but the device it powers is still going to landfill.

    1. John Brown (no body) Silver badge

      Better than currently (pun intended) where the existing stuff already goers to landfill with a more toxic battery. I'm pretty sure I've seen examples of printed components directly on to things like paper too. Maybe another step to literally printing circuits AND a power source for even cheaper, disposable sensors.

  6. Conundrum1885


    If memory serves, the weather balloons used a variant where sal ammoniac was impregnated into carbon bulk and vacuum sealed. When activated ambient moisture produced about 1.45v per cell.

  7. NeilPost


    What’s wrong with a Lemon battery ??

  8. bobbear

    A lemon battery? That's only for the toffs - we were far too poor to afford a lemon battery - we had to make do with a potato battery AND we had to eat the potato afterwards - waste not want not. (Mind, it had a funny metallic flavour..)

  9. hayzoos

    Third ink?

    I am wondering about the third ink - graphite flakes and carbon black - printed across both other inks and to the leads. I surmise this must be functioning as a resistor. Is it for limiting current or impedance matching or both or ... ?

    The first thing I thought from the initial statements was anode on one surface and cathode on the other, saturate with electrolyte and voila battery!

    I imagine capacity per cell could be increased by larger areas of ink to a limit.

    I agree with others. This has application in the disposables which are currently powered (pun intended) by the lowest cost most available, compact battery today, the button cell. In that realm, is certainly could be more environmentally friendly than button cells.

    1. Jan 0 Silver badge

      Re: Third ink?

      Well technically, the wire lead is also a resistor. In this case the graphite and carbon black is acting as an extension of the wire lead. (The pedantic might note that before wetting, the carbon is acting as one plate in an (unused) capicitor!)

      1. hayzoos

        Re: Third ink?

        The part I am trying to understand lies in the description. "across both other inks" That sounds like it is bridging and connecting both the anode and cathode within the battery. This is not normally part of a basic battery cell design. Conductivity vs. resistivity depends upon the levels of carbon black and graphite flakes in the ink.

        If the function of the third ink is only as a conductor to the leads without bridging and connecting the cathode and anode, then maybe a different description would be better. "A third conducting ink printed over each of the other inks to the wire leads. A possibility the original wording prevented me from considering.

        Yes, wires have resistance, simply lower than insulators. Only superconductors can achieve such low resistance to be considered or even be none. Air is generally a good insulator under typical conditions, high enough voltage and/or high enough conductive contamination to cause ionisation flips the behaviour to conducting.

  10. AbeSapian

    Not to Rain on Their Parade

    Didn't Alessandro Volta pretty much do the same thing in 1792?

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