Researchers at the Massachusetts Institute of Technology have successfully demonstrated a technique for fabricating a better battery using a genetically engineered virus.
They announced their technique for the battery earlier this month, maintaining that it allows them to use a much wider variety of materials for potentially higher-capacity, rechargeable batteries.
The interdisciplinary team of MIT scientists combined research in biology, chemistry, engineering and advanced nanotechnology to fabricate the battery.
Dr. Chad Mirkin, professor of materials science and engineering at Northwestern University, said he is glad to see demonstrations of practical applications of nanotechnology. This represents one of the latest applications of the ongoing advances in nanotechnology using genetically modified viruses.
"There are many examples of using genetically engineered viruses to manufacture nanomaterials," Mirkin said. "It's a merger of molecular biology and material science." He said that research in this area has been almost exclusively focused on batteries.
Applications of this type of virus battery may one day include powering personal electronics and even electric vehicles. The manufacturing process requires no organic solvents and can occur at and below room temperature. The process is described as "environmentally benign," because it requires fewer toxic components, according to MIT.
To manufacture the battery, the researchers used a genetically modified strain of the common M13 bacteriophage, a virus that consumes bacteria but which is harmless to humans. By altering the virus's DNA, the researchers were able to fabricate a battery cathode.
To do so, they altered the viruses to bond with iron phosphate on one end of their structure, and then to attach themselves to single-walled carbon nanotubes. Carbon nanotubes are used by scientists as a kind of super-small scaffolding to build nano-scale structures, and for their electric properties.
A small change in the virus's DNA produced an affinity for molecules of iron phosphate, and these molecules were built up by the virus into a structure known as nanowires. The researchers then experimented with ways of combining the nanowires with carbon nanotubes, which are excellent conductors of electricity.
They applied the idea of modifying the virus a second time to produce an affinity for bonding with carbon nanotubes. When the researchers incubated the viral iron phosphate nanowires in a suspension of carbon nanotubes, the viruses were drawn to the nanotubes, and they produced a highly conductive network in which electrons "percolate" through the carbon nanotubes on their way to the iron phosphate.
The researchers used this network as the cathode portion of their battery, and packaged the battery in a standard coin shape. The prototype was used in a simple circuit to light a green LED, and was demonstrated last month at a White House press briefing by Susan Hockfield, president of MIT.
The prototype maintained power after being charged and discharged at least 100 times in lab tests. While this falls short of current-generation lithium ion batteries, MIT Professor Angela Belcher stated she expects to improve performance with further research. Belcher, lead researcher for the battery project, is an expert in the fields of material science, engineering and biological engineering.
"We expect them to be able to go much longer," said Belcher in a press release.