MIT researches work on batteries built by viruses. Prof. Angela Belcher and her team built a lithium-ion battery which uses genetically engineered viruses to create the negatively charged anode and positively charged cathode.
The virus is a bacteriophage which infects bacteria and is harmless to humans. Good thing, else you would catch a cold every time you drive your electric car.
The batteries built with viruses has the potential to be strong enough for cars, but can also be used in gadgets.
More details on BBC News.