Engineering news
Steve Wright, senior lecturer in avionics at the University of the West of England, says battery technology is “absolutely the weakest link” when it comes to building drones, but that smaller, denser sources of power could change everything.
Currently, drones, flying cars and other electric airborne vehicles are limited in range by the size of the batteries required to power them for long distances – most can only do relatively short flights before needed to be recharged. The problem is that attempts to make batteries smaller and denser usually conflict with strategies for increasing the amount of power that can be drawn from them.
“We've got enough power, what we haven't got is enough ability to store it,” Wright told Professional Engineering. “If instead of 15 minutes they could do two hours, suddenly it's one of those things where you cross a threshold, and suddenly you're able to do things with them in the real world.”
Nanotechnology could provide that breakthrough. A new study, published today in the journal Science, tested electrodes containing porous, ‘holey’ graphene scaffolding. Graphene is a form of carbon arranged into a two-dimensional sheet, with many unusual properties. It is about 200 times stronger than steel, and has been found to be an efficient conductor of heat and electricity, hence the applications for batteries.
But until now, although nanostructured materials and graphene have shown promise, they have mainly been tested in laboratory cells with low energy density. The new paper, by scientists working across the USA, China and Saudi Arabia, describes how by fine-tuning the size of the holes in the graphene, researchers were able to achieve higher density without sacrificing power output.
“Although lithium (Li)–ion batteries currently dominate the market for powering consumer electronic devices and are making in-roads into transportation and grid storage, there is a growing technological demand for more rapid energy storage (high power) without compromising energy density,” the authors, who were led by Hongtao Sun at UCLA, write in the paper. “Thus, there is considerable interest in creating materials that combine the high energy density of battery materials with the short charging times and long cycle life of supercapacitors.”
The "wonderful thing" about graphene is that it's made of carbon and it conducts electricity, said Wright. “What they're trying to do there is create a very large contact area."
There could also be many other potential applications including lasers, policing, delivery services and high-powered sensors, he said. "We could really start to change the way people travel, communicate and move things." Graphene could help "invent an entirely new branch of engineering products and methods and equipment that we haven't really thought of yet," he added.