Tuesday, April 23, 2013

Bugs Build Batteries

Researchers have used viruses to create rechargeable batteries similar to those found in hybrid cars and laptops. Until now, batteries like this were made in chemically intensive, high-heat processes. The results could herald a low-energy, environmentally friendly alternative.
Materials chemist Angela Belcher of the Massachusetts Institute of Technology in Cambridge and her colleagues decided to try making a better battery by using biological processes. This approach is logical, Belcher says, because some of the materials in batteries, such as phosphate and iron, are present in living systems and can be easily manipulated by organisms.
The team first created an anode by genetically engineering the M13 virus, a common parasite of bacteria, to attract cobalt oxide and gold to its outer shell and then assemble into films and sheets.
The next step was to tackle the positively charged cathode, which is more challenging because it needs to be highly conductive. The team engineered the M13 viruses to accumulate ions of iron phosphate and to latch onto a highly conductive network of carbon nanotubes. Electrons could travel quickly through this system and boost the cathode's capacity. In fact, Belcher's battery had the same power performance as commercially available lithium ion batteries and could be charged and discharged at least 100 times without wearing out, the team reported online yesterday in Science.
 
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Lauren Cahoon, Science Magazine

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