Researchers fabricate micron-scale batteries

Using microcontact printing, the batteries can be stamped onto a variety of surfaces. About half the size of a human cell (five microns), the microbatteries could someday power medical implants as well as power a new generation of labs-on-a-chip, MIT said.

Genetically engineered viruses were used to assemble layers of the battery material atop an array of posts that were patterned with soft lithography. Once the battery was assembled atop the posts, the assembly was used to print arrays of batteries by transferring the material atop the posts onto a substrate. MIT engineers said they fabricated the electrolyte and anode of the micron-sized batteries, two of the three key components of a battery. Next, they will use a second genetically engineered virus to deposit a cathode atop the posts, enabling them to print complete batteries onto even curved surfaces.

MIT's researchers claim to be the first to use microcontact printing to fabricate and position microbattery electrodes, according to professor Paula Hammond, who performed the work with fellow professors Angela Belcher and Yet-Ming Chiang. They previously demonstrated the use of viruses to pattern electrolytes with their battery film.. They have now combined their viruses with microcontract printing.

The key to the MIT's battery technology is its genetically engineered virus, whose genes were altered so that they produce proteins that collect cobalt oxide molecules, which formed thin wires for the anode. By coating the metal posts with the anode and electrolyte material, it could be transfered to nearly any surface. For testing, the battery components were stamped onto a platinum structure that, together with lithium foil, formed a cathode.

The researchers are now working on genetically engineers viruses that also can deposit the cathode on the posts, as well as improving the microcontact stamp so that it can work on curved surfaces.

Partial funding was provided by the Army Research Office Institute of Collaborative Biotechnologies and the Army's Research Office Institute of Soldier Nanotechnologies.

- R. Colin Johnson
EE Times