Angela Belcher: New virus-built battery could power cars, electronic devices.
Anne Trafton, News Office
April 2, 2009
For the first time, MIT researchers have shown they can genetically
engineer viruses to build both the positively and negatively charged ends of
a lithium-ion battery.
The new virus-produced batteries have the same energy capacity and
power performance as state-of-the-art rechargeable batteries being
considered to power plug-in hybrid cars, and they could also be used to
power a range of personal electronic devices, said Angela Belcher, the MIT
materials scientist who led the research team.
The new batteries, described in the April 2 online edition of Science, could
be manufactured with a cheap and environmentally benign process: The
synthesis takes place at and below room temperature and requires no
harmful organic solvents, and the materials that go into the battery are
In a traditional lithium-ion battery, lithium ions flow between a negatively
charged anode, usually graphite, and the positively charged cathode,
usually cobalt oxide or lithium iron phosphate. Three years ago, an MIT
team led by Belcher reported that it had engineered viruses that could build
an anode by coating themselves with cobalt oxide and gold and
self-assembling to form a nanowire.
In the latest work, the team focused on building a highly powerful cathode
to pair up with the anode, said Belcher, the Germeshausen Professor of
Materials Science and Engineering and Biological Engineering. Cathodes
are more difficult to build than anodes because they must be highly
conducting to be a fast electrode, however, most candidate materials for
cathodes are highly insulating (non-conductive).
To achieve that, the researchers, including MIT Professor Gerbrand Ceder
of materials science and Associate Professor Michael Strano of chemical engineering, genetically engineered viruses that first coat themselves with
iron phosphate, then grab hold of carbon nanotubes to create a network of
highly conductive material.
Because the viruses recognize and bind specifically to certain materials
(carbon nanotubes in this case), each iron phosphate nanowire can be
electrically "wired" to conducting carbon nanotube networks. Electrons can
travel along the carbon nanotube networks, percolating throughout the
electrodes to the iron phosphate and transferring energy in a very short
The viruses are a common bacteriophage, which infect bacteria but are
harmless to humans.
The team found that incorporating carbon nanotubes increases the
cathode's conductivity without adding too much weight to the battery. In lab
tests, batteries with the new cathode material could be charged and
discharged at least 100 times without losing any capacitance. That is fewer
charge cycles than currently available lithium-ion batteries, but "we expect
them to be able to go much longer," Belcher said.
The prototype is packaged as a typical coin cell battery, but the technology
allows for the assembly of very lightweight, flexible and conformable
batteries that can take the shape of their container.
Last week, MIT President Susan Hockfield took the prototype battery to a
press briefing at the White House where she and U.S. President Barack
Obama spoke about the need for federal funding to advance new cleanenergy
Now that the researchers have demonstrated they can wire virus batteries
at the nanoscale, they intend to pursue even better batteries using
materials with higher voltage and capacitance, such as manganese
phosphate and nickel phosphate, said Belcher. Once that next generation
is ready, the technology could go into commercial production, she said.
Lead authors of the Science paper are Yun Jung Lee and Hyunjung Yi,
graduate students in materials science and engineering. Other authors are
Woo-Jae Kim, postdoctoral fellow in chemical engineering; Kisuk Kang,
recent MIT PhD recipient in materials science and engineering; and Dong
Soo Yun, research engineer in materials science and engineering.
The research was funded by the Army Research Office Institute of the
Institute of Collaborative Technologies, and the National Science
Foundation through tthe Materials Research Science and Engineering
A version of this article appeared in MIT Tech Talk on April 8, 2009. MIT News article.