VIRUS BATTERY
Viruses have been used to help build batteries that may one day power cars and all types of electronic devices.
The speed and relatively cheap cost of manufacturing virus batteries could prove attractive to industry.
In what is claimed to be the first potential applications of synthetic biology, researchers have now shown that viruses, otherwise harmful to humans, can power cars and electronic gadgets.
A team at the Massachusetts Institute of Technology has revealed that it can genetically engineer viruses to build both the positively and negatively charged ends of a lithiumion battery, the Science journal reported.
“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 electronic devices,” lead researcher Angela Belcher said.
Professor Angela Belcher, who led the research team, said: “Our material is powerful enough to be able to be used in a car battery.”
The team from MIT in the US is now working on higher power batteries.Scientists at MIT used the viruses to build both the positively and negatively charged ends of a battery, the cathode and anode, the journal Science reports.
A battery typically has four key components – the anode and cathode, an electrolyte that flows between them, and a separator to keep the anode and cathode apart.Essentially, a battery turns chemical energy into electrochemical energy when an electron flow passes from the negative end to the positive end through a conductive chemical, the electrolyte.
Researchers constructed a lithium-ion battery, similar to those used in millions of devices, but one which uses genetically engineered viruses to create the negatively charged anode and positively charged cathode.
The virus is a so-called common bacteriophage which infects bacteria and is harmless to humans.
The virus picks up a carbon nanotube after being genetically engineered
In fact, according to them, the new batteries 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 non-toxic. 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.
Three years ago the MIT scientists manipulated genes inside a virus that coaxed the particles to grow and self-assemble to form a nanowire anode one-tenth the width of a human hair.The microbes are encouraged to collect exotic materials – cobalt oxide and gold – and because the particles are negatively charged, they can be formed into a dense, virus-loaded film which acts as an anode and “grows” on a polymer separator.Researchers, including MIT Professor Gerbrand Ceder and Associate Professor Michael Strano, have now developed a highly powerful cathode.
The work was more difficult because the material had to be highly conductive in order to be effective and most candidate materials for cathodes are highly insulating.
The virus was coaxed into binding with iron phosphate and then carbon nanotubes to create a highly conductive material.The batteries have the same energy capacity and power performance as rechargeable batteries used to power plug-in hybrid cars.
The prototype battery is currently the size of a coin but the scientists believe it can be scaled and be used to create flexible batteries that can take the shape of their container, which is perfect for mobile or small devices.
The researchers are now looking for better materials to work with the viruses to create a next-generation battery, which is even higher powered.
“Scale is the issue,” admitted Professor Belcher. “But we are not going to scale until we have the right material. We believe this is possible and has commercial implications otherwise we would not be researching in this area.”Currently, the virus battery can only be charged and discharged at least 100 times before it begins to lose its capacity to store a charge, but Professor Belcher said “we expect them to be able to go much longer”.
The process to build the batteries uses no harmful or toxic materials and so is attractive from an environmental point of view.
