Ultra-small batteries powered by viruses

Researchers at Massachusetts Institute of Technology (MIT) are using viruses to create tiny batteries that can store up to three times as much energy as conventional power systems.

The team, led by MIT professors Angela Belcher, Paula Hammond and Yet-Ming Chiang, genetically modified a virus so that it attracts cobalt oxide and gold, and assembled the metals into ultra-thin wires just six nanometres in diameter.

The viruses can be cloned to assemble lithium batteries ranging in size from a grain of rice to a full-sized product.

"Once we have altered the genes of the virus to grow the electrode material, we can easily clone millions of identical copies of the virus to use in assembling our batteries," said Professor Belcher.

"For the metal oxide we chose cobalt oxide because it has very good specific capacity, which will produce batteries with high energy density.

"This allows it to store two or three times more energy for its size and weight compared to previous battery electrode materials. And adding the gold further increased the wires' energy density."

Furthermore the viruses do not need a special environment and the reaction takes place at room temperature, lowering the production costs of any virus assembly system.

Experts estimate that current battery technology performance improvements will be limited to around eight per cent a year, but this new technology could lead to a dramatic improvement in these figures.

The energy density of current batteries is a major sticking point in the development of long lasting laptops and electric cars.