If we asked you to list the words which came into your head when we said “virus,” we’re pretty sure they’d revolve the negative feelings of being sick, not the positive, good things viruses can do.
We wouldn’t blame you, either: just uttering the word ‘virus’ makes us feel sub-par, but for a team of researches at MIT, viruses mean something other than being stuck in bed watching reruns of classic 1980s sitcoms. No, for them, viruses mean travelling further in your electric car.
In a paper published yesterday in Nature Communications entitled ‘Biologically enhanced cathode design for improved capacity and cycle life for lithium-oxygen batteries‘, the five authors of the paper say they’ve been able to successfully use a genetically-modified variant of the M13 virus — apparently a fairly innocuous virus — to help build nanowires with phenomenal surface area. The larger the surface area, the more energy the nanowires can transfer at any given moment, making them ideal for use as an electrode in an electric car battery.
Instead of using traditional manufacturing processes to build the nanowires — which have traditionally required a great deal of heat and dangerous chemicals to produce — the MIT researchers found they could modify the M13 virus to capture magnesium molecules from water, surrounding the virus to create long, nanowire structures with a heavily spiked surface. Being spiky instead of smooth, the nano wires have a much greater surface area, leading to the improvement in charge and discharge capabilities.
By then adding a tiny amount of palladium to the virus-built manganese oxide wires to act as a catalyst, the researchers discovered the wires could not only transfer large amounts of current through them, but could store two to three times the energy per pound of current lithium-ion batteries.
The nanowires — about the same width as a red blood cell — were tested in lithium-air batteries, where lithium is used as the anode and oxygen from the air is used as the cathode (or rather, a porous material capable of harvesting the oxygen in the air from outside the battery is used as the cathode). Because of this, lithium-air batteries are far lighter than conventional battery technologies, and are already used in many applications where weight and size is important, such as hearing aid batteries.
But although lithium-air batteries are already found in many single-use, disposable batteries, rechargeable lithium-air batteries have long been considered the holy grail of electric car energy storage, due to their light weight and high energy storage capabilities which theoretically rivals the energy density of gasoline.
It’s no surprise then, that automakers like Tesla are already researching the use of lithium-air batteries in electric cars. In fact, back in September, Tesla was awarded a patent for a new hybrid battery pack made of conventional lithium-ion and metal-air batteries, which could theoretically travel more than 400 miles without recharging.
As for MIT’s ‘biological’ metal-air battery, made using wires surrounding a genetically-modified virus? At the moment the researchers say there’s some way to go before the technology could be used in a commercial application, and hint that using viruses to build nanowires on an industrial scale may prove difficult.
But if you’re tired of just 100 miles of range form your EV, this latest piece of exciting research hints at a future where like gasoline cars, we only have to ‘fill up’ every few hundred miles or so.
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