Firstly, the biology in question is that of viruses and, secondly, research in lithium-air batteries has elicited big interest according to David Chandler’s November 13, 2013 Massachusetts Institute of Technology (MIT) news piece (also on EurekAlert and Nanowerk),
Lithium-air batteries have become a hot research area in recent years: They hold the promise of drastically increasing power per battery weight, which could lead, for example, to electric cars with a much greater driving range. But bringing that promise to reality has faced a number of challenges, ….
Now, MIT researchers have found that adding genetically modified viruses to the production of nanowires — wires that are about the width of a red blood cell, and which can serve as one of a battery’s electrodes — could help solve some of these problems.
Lithium-air batteries can also be referred to as lithiium-oxygen batteries, although Chandler does not choose to mix terms as he goes on to describe the process the researchers developed,
The researchers produced an array of nanowires, each about 80 nanometers across, using a genetically modified virus called M13, which can capture molecules of metals from water and bind them into structural shapes. In this case, wires of manganese oxide — a “favorite material” for a lithium-air battery’s cathode, Belcher says — were actually made by the viruses. But unlike wires “grown” through conventional chemical methods, these virus-built nanowires have a rough, spiky surface, which dramatically increases their surface area.
Belcher, the W.M. Keck Professor of Energy and a member of MIT’s Koch Institute for Integrative Cancer Research, explains that this process of biosynthesis is “really similar to how an abalone grows its shell” — in that case, by collecting calcium from seawater and depositing it into a solid, linked structure.
The increase in surface area produced by this method can provide “a big advantage,” Belcher says, in lithium-air batteries’ rate of charging and discharging. But the process also has other potential advantages, she says: Unlike conventional fabrication methods, which involve energy-intensive high temperatures and hazardous chemicals, this process can be carried out at room temperature using a water-based process.
Also, rather than isolated wires, the viruses naturally produce a three-dimensional structure of cross-linked wires, which provides greater stability for an electrode.
A final part of the process is the addition of a small amount of a metal, such as palladium, which greatly increases the electrical conductivity of the nanowires and allows them to catalyze reactions that take place during charging and discharging. Other groups have tried to produce such batteries using pure or highly concentrated metals as the electrodes, but this new process drastically lowers how much of the expensive material is needed.
Altogether, these modifications have the potential to produce a battery that could provide two to three times greater energy density — the amount of energy that can be stored for a given weight — than today’s best lithium-ion batteries, a closely related technology that is today’s top contender, the researchers say.
MIT has produced a video highlighting the researchers’ work (this runs longer than most of the materials I embed here at approximately 11 mins. 25 secs.),
For those who want to know more about this intriguing and speculative work,
Biologically enhanced cathode design for improved capacity and cycle life for lithium-oxygen batteries by Dahyun Oh, Jifa Qi, Yi-Chun Lu, Yong Zhang, Yang Shao-Horn, & Angela M. Belcher. Nature Communications 4, Article number: 2756 doi:10.1038/ncomms3756 Published 13 November 2013
This article is behind a paywall.
ETA Nov. 15, 2013: Dexter Johnson offers more context and information, including commercialization issues, about lithium-air batteries and lithium-ion batteries in his Nov. 14, 2013 posting on the Nanoclast blog (on the IEEE [Institute of Electrical and Electronics Engineers] website).