Researchers at Rice University have managed to build an ultra-slim, ultra-flexible battery that could be the key to powering smartwatches and fitness bands for longer and to creating folding phones.
Building a battery small enough to fit inside a wearable tech device, be it smartglasses or a smartwatch, isn't difficult. However, creating one small and light enough that can actually offer the user more than a few hours' continued use is still a huge challenge.
Likewise, Samsung and LG might have wowed the world with their first flexible-display smartphones this year, but until the battery that powers their screens is equally open to movement, new and exciting phone shapes and designs are still years away from becoming a reality.
What separates the cell created by the team lead by Rice chemist James Tour from other attempts is not its impressive size -- it's a hundredth of an inch thick -- but that it behaves like a lithium-ion battery: it charges quickly, discharges slowly and is tough enough to survive 10,000 charging cycles. Yet, the battery is lithium-free.
The best materials for making batteries tend to be less than flexible and the best materials for making flexible cells tend not to offer a high storage capacity or the power to run something as big as a smartphone, for example. Therefore, there is great interest around the Rice University team's work and the fact that it might have identified a material that offers the best of both worlds.
"This is not easy to do, because materials with such high capacity are usually brittle," said Tour. "And we've had really good, flexible carbon storage systems in the past, but carbon as a material has never hit the theoretical value that can be found in inorganic systems, and nickel fluoride in particular."
The battery they have created is made from a layer of nickel and uses an electrolyte of potassium hydroxide in polyvinyl alcohol. It can be built up, layer by layer to increase capacity based on what it is going to be used for -- a fitness tracker, smartphone or tablet.
"The numbers are exceedingly high in the power that it can deliver, and it's a very simple method to make high-powered systems," Tour said. "We're already talking with companies interested in commercializing this."
Tour's paper, co-authored by Rice graduate student Changsheng Xiang and postdoctoral researcher Gunuk Wang, is published in the latest edition of the Journal of the American Chemical Society.