Algae used to create a quick-charge, lightweight battery
September 13, 2009
Algae blooms are unpleasant and unpredictable phenomena that arise quickly and strike seas and oceans often causing serious problems to local ecosystems. But in an effort to try and find a use for such algae, a research team from Uppsala University, Sweden, has recently managed to design a record-breaking "green" lightweight battery that is incredibly easy to produce and could just even out the environmental consequences of these blooms.
As the authors explained in a paper published in the latest edition of the journal Nano Letters, the key idea behind the design of this peculiar battery was to exploit the unique cellulose structure of the Cladophora algae, which is characterized by a very large surface area.
By coating this structure with an extremely thin (only 50 nanometers) layer of conducting polymer, the team managed to produce a battery that weighs very little and can be fully charged in as little time as 11.3 seconds at 320 mA, still retaining good cycling capabilities.
The battery charge, in fact, decreases by only six percent after 100 charge/discharge cycles. Prof. Maria Strømme, who led the research efforts, pointed out that this figure was for a completely non-optimized packaging. The team is now working on this specific aspect and has already achieved over 1000 charge cycles.
This is a major step forward for conductive polymer batteries, which are known to be more environmentally friendly than most metal containing electrode materials, but had shown very poor cycling stability so far, making them unfit for commercial applications.
But due to its characteristics, the Cladophora-polypyrrole battery could actually be mass-produced, particularly for applications where cost and/or weight are an issue, opening a plethora of new possibilities for low-cost electronics.
"We are talking about a battery that mainly consists of paper and salt water and that can theoretically be made in your own kitchen (if you have a strong mixer) without the major energy input needed to create today’s batteries," Prof. Strømme told us in an email.
"With the technique fully developed, I believe that we may see applications that we cannot really dream of today. Try to imagine what you can create when a battery can be integrated into wall papers, clothes, the packages of your medicines, etc."
Don't expect to find these batteries powering an iPhone or your next electric car anytime soon, though, as one of the major drawbacks of cellulose-polymer battery technology appears to be the relatively low storage capabilities when compared to metal electrode technology — approx. 25 Wh/kg for the team's design against Lithium-ion's 100-160 Wh/kg.
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