A group of researchers at the Massachusetts Institute of Technology in Cambridge are betting that viruses could be the key to making low-energy, 'green'-friendly batteries. The researchers replicate the inner workings of a battery using biological processes. In their series of studies working with the M13 virus, they were able to engineer both an anode and a cathode within the virus, with the outer shell acting as the anode and the virus' carbon nanotubes as the cathode. Tests found the resulting battery to have performance comparable to commercial lithium-ion batteries. However, since the virus battery offers no performance gains compared to current battery technology, further inroads must be made before viruses can be a viable source of battery technology. In my opinion, it will only be a matter of time before this technology is properly optimized; the prospects of an low-energy, environmentally-friendly battery are just too attractive in this green-conscious era.
link to article: http://sciencenow.sciencemag.org/cgi/content/full/2009/403/1