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A new article in Nature Communications from a research group in MIT has made innovative use of a genetically modified virus called M13 to build a network of cross-linked nanowires to serve as an electrode in a lithium-air battery. Lithium-air batteries are the subject of intense research interest as they have the potential to produce greatly increased power per battery weight compared to other batteries, which for example would be advantageous in increasing the driving range of electric cars. However, development of these batteries has been frustrated by issues such as the need to develop better, more durable materials for the batteries' electrodes and improving the capacity of the batteries for multiple charging-discharging cycles.

In the Nature Communications study, M13 was used to make nanowires of manganese oxide, which is a favoured material for manufacture of lithium-air batteries’ cathodes. The surface area of the nanowires was increased compared to wires built by chemical methods due to their rough, spiky surface. This should have the advantage of improving the rate of charging-discharging. Also, the process was much less hazardous than conventional methods that involve high temperatures and hazardous chemicals whereas this process was performed at room temperature using a water-based process. The three-dimensional structure of the virally-constructed wires also provides increased electrode stability. Conductivity of the nanowires was improved by including a small amount of palladium. Thus the need for expensive materials such as pure or highly concentrated metals is reduced as compared to conventional methods. Taken together, the potential is there to build batteries with greatly increased power per battery weight compared to lithium-ion batteries.

This research is at an early stage and would not yet be viable for commercial production. It looked only at cathode production and was only successfully tested through 50 charging/discharging cycles whereas for practical use a battery must be capable of withstanding thousands of these cycles. But the potential is there for biotechnology to help build more powerful batteries with positive impact on our environment in the future.

Sources

Massachusetts Institute of Technology. "Better batteries through biology? Modified viruses boost battery performance." ScienceDaily, 13 Nov. 2013. [Accessed 19 November 2013]
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Dahyun Oh, D. et al, 2013. Biologically enhanced cathode design for improved capacity and cycle life for lithium-oxygen batteries. Nature Communications, 2013; 4 DOI: 10.1038/ncomms3756