[LINK] 'Greener' Batteries

stephen at melbpc.org.au stephen at melbpc.org.au
Sun Apr 5 02:34:20 AEDT 2009

Here's another report ..

Virus Power: MIT completes nanomachine battery

By Tim Conneally | Published April 3, 2009, 4:15 PM

Angela Belcher and her team of bioengineers at the Massachusetts 
Institute of Technology (MIT), have turned the concept of a virus-built 
battery into a reality.

For the last five years, the team has been engineering a virus known as 
M13 bacteriophage, which is attracted to inorganic materials. 

Each virus coats itself with gold and cobalt oxide, effectively turning 
itself into a fragment of nanowire. 

When these viruses are then chained together, they form a film that can 
be used as an anode, or the part of a battery that carries a negative 
ionic charge. 

But that discovery was made nearly three years ago, and was only half of 
the simple negative and positive elements needed to form a working 

Ions from the negatively-charged anode flow to the positively-charged 
cathode to "charge" a battery, and flow in the opposite direction 
to "discharge" that electricity through laptops, mobile phones, and other 
such devices.

To create the cathode, the team engineered viruses that would attract 
iron phosphate and carbon nanotubes (cylindrical carbon molecules 
frequently used in nanotechnology), which created a highly conductive 
material that had practically no weight.

With both elements in place, the team could create a micro-battery 
capable of around 100 charges. The prototype took this model and inflated 
it to the size of a button cell battery which powers a simple LED.

While size is still an issue for these batteries, shape is not. The team 
hopes to be able to create a battery that can take the shape of whatever 
container in which it is housed.

> Viruses Used to Grow "Greener" Batteries
> Charles Q. Choi for National Geographic News, April 3, 2009 
> With the help of a common virus, scientists have built a battery that 
> rivals the state-of-the-art rechargeable models now powering personal 
> electronics and hybrid vehicles. 
> The hope is to replace the costly, toxic electrodes currently used in 
> lithium-ion batteries. 
> The researchers modified the M13 virus, which infects only bacteria, to 
> grow proteins on its surface that attract amorphous iron phosphate. 
> The result: Wires nanometers thick of the material, which is cheaper 
> and environmentally friendlier than ones currently used to make 
> electrodes for lithium-ion batteries. 
> The scientists also programmed the virus so one end became sticky to 
> carbon nanotubes, which are extraordinarily good conductors of 
> electricity. 
> Electrons easily travel along carbon nanotubes to the amorphous iron 
> phosphate networks, transferring energy in a very short time. 
> Using these ingredients, the researchers devised coin-sized batteries 
> comparable in performance to commercial lithium-ion batteries. 
> "The more genetic engineering we did, the better it got," researcher 
> Angela Belcher, a materials scientist at the Massachusetts Institute of 
> Technology. 
> Carbon nanotubes are still expensive, and researchers debate what risks 
> they might pose to the environment. If the nanotubes become a barrier, 
> the same could be performed with other good electrical conductors 
> such as silver or gold, Belcher said. 
> While her team is still in the early stages of its work, Belcher thinks 
> the project could soon get "twice the power performance of what we 
> demonstrated with this proof of principle here." 
> Findings detailed online in the April 2 issue of the journal 'Science' 
> --
> Cheers,
> Stephen
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