Cambridge (MA) – Miniature devices of the future could be powered by tiny new batteries that are about half the size of a human cell. Researchers from the Massachusetts Institute of Technology (MIT) have come up with an idea to leverage characteristics of viruses to built small power sources that one day could supply the smallest electronics with electricity.
Finding enough space for batteries in shrinking consumer electronics devices are one of the big challenges of hardware designers. But while the available space in today’s consumer electronics still seems to be manageable and evolve over time, there are less convenient solutions available for tiny microdevices such as implantable medical sensors.
In the past, we have seen futuristic announcements of entire nano-power plants that are imagined to be implanted within arteries to use the blood flow to generate electricity where it is needed, but these devices are still very much science fiction. Before these power plants arrive, micro batteries are more likely to be built – and one of the more promising concepts was revealed by MIT researchers today.
To come up with all three critical components of a micro-battery - the anode, cathode and the electrolyte that separates the two – the project group employed soft lithography on “a rubbery material” o create a pattern of tiny posts either four or eight millionths of a meter in diameter. On top of these posts, they then built several layers of two polymers that together act as the solid electrolyte and battery separator.
Viruses that self-assemble atop the polymer layers on the posts were chosen to form the anode: Through a previously known method, the researchers were able to altered the virus’ genes so that it produces protein coats that collect molecules of cobalt oxide to form ultrathin wires – and ultimately the anode.
What the researchers achieved is described as tiny posts, each covered with layers of electrolyte and the cobalt oxide anode: “Then we turn the stamp over and transfer the electrolyte and anode to a platinum structure” that, together with lithium foil, is used for testing,” said MIT professors Paula Hammond. She noted that “the resulting electrode arrays exhibit full electrochemical functionality.”
The announcement only covers two of the three necessary components – the cathode is still missing. However, the researchers said that a complete battery is on its way. “To our knowledge, this is the first instance in which microcontact printing has been used to fabricate and position micro-battery electrodes and the first use of virus-based assembly in such a process,” Hammond said.