Batteries are heavy and an important part of a Soldier's primary logistical load. To reduce this load, MIT engineers in the USA have been working on pioneering research to develop tiny microbatteries about half the size of a human cell, built with viruses.
Two of the three components of a battery have been assembled and tested and a complete battery is on the horizon which could one day power a range of miniature devices, from labs-on-a-chip to implantable medical sensors, by stamping them onto a variety of surfaces.
The MIT researchers used a technique that does not require expensive equipment and is done at room temperature to create both an anode and an electrolyte. Batteries consist of two opposite electrodes an anode and cathode which are separated by an electrolyte.
Lithography was used on a clear rubbery material to create a pattern of ultra small posts four or eight millionths of a meter in diameter. Several layers of two polymers which when combined act as the solid electrolyte and battery separator were dropped on top of the posts.
The engineers reported that the viruses preferentially self-assembled atop of the polymer layers on the posts, ultimately forming the anode. This altered the virus's genes to make protein coats that collect molecules of cobalt oxide to form ultra thin wires - together, the anode. The final result was a stamp of tiny posts, each covered with layers of electrolyte and the cobalt oxide anode. They turned the stamp over and transferred the electrolyte and anode to a platinum structure that, together with lithium foil, was used for testing. The team concludes that the resulting electrode arrays exhibited full electrochemical functionality.
The third part of the battery - the cathode is being developed using the viral assembly technique. They are also exploring a stamp for use on curved surfaces.
The work was funded by the Army Research Office Institute of Collaborative Biotechnologies, the Army Research Office Institute of Soldier Nanotechnologies, and the David and Lucille Packard Foundation.