Last updated May 4, 2018 at 3:49 pm
When space is at a premium – there’s only one place to go.
Credit: MF3d
Your devices are getting smaller, thinner and faster but how do we ensure we aren’t left powerless as the battery size shrinks along with our tech?
A new battery design, inspired by the neck straining heights of big city skyscrapers, may be the answer.
Batteries are very simple devices. Their structure exists of three parts – two electrodes (an anode and a cathode) and an electrolyte sandwiched between them.
Even the most innovative miniature batteries can only do so much with a simple flat sandwich structure.
US scientists have created a miniature 3D lithium ion battery that doesn’t skimp on power. The inspiration for this new battery comes from another situation where space is at a premium – the hustle and bustle of densely populated cities.
“You need to re-design the battery to be like a skyscraper in New York instead of a ranch house in California,” says lead scientist Prof Bruce Dunn, from the University of California.
A change in architecture
Just like New York city, when you run out of floor space the only way to go is up. Although not a completely new concept in itself, previous studies have only been able to build half of a 3D battery, creating anodes and cathodes that are stable on their own but failed when trying to squeeze all of the parts together.
Thanks to advances in micro manufacturing, the research team were able to overcome any issue with assembly using innovative “concentric-tube” design which carved precisely spaced cylinders into silicon wafers.
“That’s something the battery world just does not do,” Dunn says.
The 3D batteries developed by Janet I. Hur, Leland C. Smith, and Bruce Dunn. Credit: Hur et al./Joule
The battery was completed by applying a layer of polymer electrode and filling the cylinder structure with a liquid cathode material.
“We can use semiconductor processing and a conformal electrolyte to make one that is compatible with the demands of small internet-connected devices,” said Dunn.
The resulting battery had a miniscule footprint of 0.09 cm2 (about the size of 100 grains of salt) and reported one of the highest power densities for 3D batteries of 5.2 milliwatt-hours per cm2.
The future looks even brighter
The scientists point out that the 3D battery has not yet reached its full potential and with further modification of components and manufacturing the energy density and stability is likely to get much better.
There’s still a fair way to go before the batteries can be removed from the safety of the glove box – they must be protected against the sorts of environments that most portable devices end up in.
“Another challenge with batteries is always the packaging,” he adds. “You need to seal them up, keep them small, and make sure they function just as well in the real world as in the glovebox.”
The study was reported in Joule.
