MIT team touts sci-fi style "virus battery"

It might sound like something out of a science fiction film, but researchers at MIT reckon they have developed a way of making batteries from genetically engineered viruses that promises to reduce the cost and environmental impact of a wide range of battery technologies, including those used in electric cars.

One of the main criticisms of electric cars is that the benefits gained from reduced emissions are undermined by the energy and toxic components used in the manufacture of the batteries.

However, according to research published yesterday in Science, the MIT team has found a potential solution to this problem with the development of a "cheap and environmentally benign" manufacturing process that can take place at room temperature, requires no harmful organic solvents and results in a lithium-ion battery that contains only non-toxic materials.

The technology is based on genetically engineered viruses that are used to build both the positively and negatively charged ends of the battery.

Conventional lithium-ion batteries see lithium ions flow between a negatively charged anode, usually made from graphite, and a positively charged cathode, typically made from cobalt oxide or lithium iron phosphate.

However, three years ago an MIT team led by Professor Angela Belcher engineered viruses that could build an anode by coating themselves with cobalt oxide and gold and self-assembling to form a nanowire. Now the team has successfully developed viruses that can create a cathode by coating themselves with iron phosphate and then grabbing hold of carbon nanotubes.

Belcher explained that the virus created a network of highly conductive material and because it is able to recognise and bind specifically to certain materials, each iron phosphate nanowire can be electrically "wired" to conducting carbon nanotube networks. As a result electrons can travel along the carbon nanotube networks, percolating throughout the electrodes to the iron phosphate and transferring energy in a very short time.

While the idea of "virus batteries" is bound to spark health concerns in some observers, the team said that the viruses used are common bacteriophage, which infect bacteria but are harmless to humans.

The prototype coin cell battery has already been demonstrated to Barack Obama at a meeting between the president and MIT president Susan Hockfield last week and the team is now working on developing the technology using materials with higher voltage and capacitance, such as manganese phosphate and nickel phosphate.

Belcher said that the team was also looking to improve the number of charge cycles the batteries can go through before they being to lose capacity. Currently, the cathode material can only be charged and discharged 100 times before it begins to lose capacity, but Belcher said she expected them to be " able to go much longer" in the future.

She added that once the next generation of improved batteries is completed the technology could go into commercial production.