Batteries built by viruses

Researchers have genetically engineered biological viruses to form the anode and cathode of a battery. MIT researcher Angela Belcher and her colleagues manipulated the genes of a harmless virus so that the bug coats itself in tiny iron phosphate particles and connects to highly-conductive carbon nanotubes. From Science News:
Ions and electrons can move through smaller particles more quickly. But fabricating nano-sized particles of iron phosphate is a difficult and expensive process, the researchers say.

So Belcher’s team let the virus do the work. By manipulating a gene of the M13 virus to make the viruses coat themselves in iron phosphate, the researchers created very small iron phosphate particles.

“We’re using a biological template that’s already on the nanoscale,” Belcher says.

Tweaking a second gene made one end of the virus bind to carbon nanotubes, which conduct energy well. The resulting network of iron phosphate-coated viruses and carbon nanotubes formed a highly conductive cathode, one that ions and electrons could move through quickly.
"Viruses could power devices"