Scientists at the Massachusetts Institute of Technology have demonstrated how a genetically modified virus can be used to construct both the cathode and anode of a lithium-ion battery.
Virus-built rechargeable batteries would have the same power capacity as the batteries used to power hybrid cars, project leader Professor Angela Belcher said in an MIT press statement on Thursday.
In a paper published in the journal Science, the research team explained that they manipulated two genes of the M13 virus to equip the bacteriophage with peptide groups that attract single-walled carbon nanotubes at one end, while the other end of the virus was equipped with peptides that nucleate amorphous iron phosphate.
Combining the nanotubes with the iron phosphate created a highly conductive material that was used in a cathode, said the MIT statement. Battery energy was transferred in "a very short time", as electrons could travel along the carbon nanotube networks and percolate throughout the electrodes.
Three years ago, a research team led by Belcher used a similar virus-modification technique to build an anode — the genetically modified virus coated itself with cobalt oxide and gold to assemble a nanowire.
In tests, researchers found the virus-built battery could be recharged 100 times without losing capacitance. The incorporation of carbon nanotubes increased battery conductivity without adding too much weight, said the statement.
The team now plans to genetically modify microbes to assemble materials with higher voltage and capacitance, such as manganese phosphate and nickel phosphate. Once this is achieved the technology could go into commercial production, said Belcher.
These advances feed into wider cross-disciplinary investigations into energy harvesting: the technique of extracting power from the environment. Current research efforts focus on both biological and non-biological systems. Non-biological study includes research into mechanical, thermal and electromagnetic systems. Biological systems such as photosynthesis and metabolic pathways, already closely analyzed for medical and scientific purposes, are also seen as potential sources of energy for electronic systems, with a cross-over field — synthetic biology — using ideas from living systems in designed processes.