Researchers are chasing better electric car batteries that are more efficient and, as a result, able to carry a car farther between charges. Super lightweight lithium air batteries are promising, but the technology isn’t ready yet.
MIT researchers published a paper in Nature Communications today detailing an unusual manufacturing technique that could help the batteries edge closer to being ready. Each time a lithium air battery charges or discharges, it needs a location for electrochemical reactions to take place. Nanowires — tiny wires the width of a red blood cell — do the job nicely, but generally need to be manufactured at extremely high temperatures with dangerous chemicals.
The researchers found they could make the nanowires at room temperature by relying on an unexpected ally: genetically modified viruses. The viruses capture metal molecules from water and build them into the long nanowires with spiky surfaces. The spikes create a greater surface area than the smooth, industrially produced nanowires have, which creates more area for electrochemical activity to take place. This allows faster charges and discharges.
The researchers also increased the nanowires’ conductivity by adding a small amount of metal. Together, the advancements could lead to a battery that stores two or three times more energy per pound than current lithium-ion batteries.
The nanowires were only tested for 50 charges and discharges, which means much more work remains before they could be used in an actual car, where thousands of charges are to be expected. It also may be difficult to scale using viruses to create nanowires.
Electric car manufacturers like Tesla have taken a strong interest in lithium air batteries because, aside from their light weight, they make use of oxygen, which is abundant and free. Theoretically, their energy density could resemble that of gasoline, leading to electric cars that could travel currently unheard of distances on a single charge.