3D printing tiny batteries

Jun 18, 2013
For the first time, a research team from the Wyss Institute at Harvard University and the University of Illinois at Urbana-Champaign demonstrated the ability to 3-D print a battery. This image shows the interlaced stack of electrodes that were printed layer by layer to create the working anode and cathode of a microbattery. Credit: Ke Sun, Teng-Sing Wei, Jennifer A. Lewis, Shen J. Dillon

(Phys.org) —3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand. The printed microbatteries could supply electricity to tiny devices in fields from medicine to communications, including many that have lingered on lab benches for lack of a battery small enough to fit the device, yet provide enough stored energy to power them.

To make the microbatteries, a team based at Harvard University and the University of Illinois at Urbana-Champaign printed precisely interlaced stacks of tiny battery , each less than the width of a human hair.

"Not only did we demonstrate for the first time that we can 3D-print a battery, we demonstrated it in the most rigorous way," said Jennifer Lewis, Ph.D., senior author of the study, who is also the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard School of Engineering and Applied Sciences (SEAS), and a Core Faculty Member of the Wyss Institute for Biologically Inspired Engineering at Harvard University. Lewis led the project in her prior position at the University of Illinois at Urbana-Champaign, in collaboration with co-author Shen Dillon, an Assistant Professor of there.

The results will be published online on June 18 in the journal Advanced Materials.

In recent years engineers have invented many miniaturized devices, including , flying insect-like robots, and tiny cameras and microphones that fit on a pair of glasses. But often the batteries that power them are as large or larger than the devices themselves—which defeats the purpose of building small.

To get around this problem, manufacturers have traditionally deposited of to build the electrodes. However, due to their ultra-thin design, these solid-state micro-batteries do not pack sufficient energy to power tomorrow's miniaturized devices.

To create the microbattery, a custom-built 3D printer extrudes special inks through a nozzle narrower than a human hair. Those inks solidify to create the battery's anode (red) and cathode (purple), layer by layer. A case (green) then encloses the electrodes and the electrolyte solution added to create a working microbattery. Credit: Ke Sun, Bok Yeop Ahn, Jennifer Lewis, Shen J. Dillon

The scientists realized they could pack more energy if they could create stacks of tightly interlaced, ultrathin electrodes that were built out of plane. For this they turned to 3D printing. 3D printers follow instructions from three-dimensional computer drawings, depositing successive layers of material—inks—to build a physical object from the ground up, much like stacking a deck of cards one at a time. The technique is used in a range of fields, from producing crowns in dental labs to rapid prototyping of aerospace, automotive, and consumer goods. Lewis' group has greatly expanded the capabilities of 3D printing. They have designed a broad range of functional inks—inks with useful chemical and electrical properties. And they have used those inks with their custom-built 3D printers to create precise structures with the electronic, optical, mechanical, or biologically relevant properties they want.

To print 3D electrodes, Lewis' group first created and tested several specialized inks. Unlike the ink in an office inkjet printer, which comes out as droplets of liquid that wet the page, the inks developed for extrusion-based 3D printing must fulfill two difficult requirements. They must exit fine nozzles like toothpaste from a tube, and they must immediately harden into their final form.


In this video, a 3D-printer nozzle narrower than a human hair lays down a specially formulated "ink" layer by layer to build a microbattery's anode from the ground up. Unlike ink in an office inkjet printer, which comes out as droplets of liquid and wets a piece of paper, these 3D-printer inks are specially formulated to exit the nozzle like toothpaste from a tube, then immediately harden into layers as narrow as those produced by thin-film manufacturing methods. In addition, the inks contain nanoparticles of a lithium metal oxide compound that give the anode the proper electrical properties. Credit: Teng-Sing Wei, Bok Yeop Ahn, Jennifer Lewis

In this case, the inks also had to function as electrochemically active materials to create working anodes and cathodes, and they had to harden into layers that are as narrow as those produced by thin-film manufacturing methods. To accomplish these goals, the researchers created an ink for the anode with nanoparticles of one lithium metal oxide compound, and an ink for the cathode from nanoparticles of another. The printer deposited the inks onto the teeth of two gold combs, creating a tightly interlaced stack of anodes and cathodes. Then the researchers packaged the electrodes into a tiny container and filled it with an electrolyte solution to complete the battery.

Next, they measured how much energy could be packed into the tiny batteries, how much power they could deliver, and how long they held a charge. "The electrochemical performance is comparable to commercial batteries in terms of charge and discharge rate, cycle life and energy densities. We're just able to achieve this on a much smaller scale," Dillon said.

"Jennifer's innovative microbattery ink designs dramatically expand the practical uses of 3D printing, and simultaneously open up entirely new possibilities for miniaturization of all types of devices, both medical and non-medical. It's tremendously exciting," said Wyss Founding Director Donald Ingber, M.D., Ph.D.

Explore further: Study reveals new characteristics of complex oxide surfaces

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Matthewwa25
2 / 5 (4) Jun 18, 2013
This is really cool!
ValeriaT
1.4 / 5 (7) Jun 18, 2013
It's cool but still an economical nonsense. Every other method (like the screen printing) would provide faster/cheaper results.
antialias_physorg
4 / 5 (4) Jun 19, 2013
It's cool but still an economical nonsense. Every other method (like the screen printing) would provide faster/cheaper results.

And you think you will eventually have a screen printing machine at home?

It's quite possible that we'll have 3D printers of this calibre in our homes at some point...as naturally as we have dish washers now. Need a new phone (or any kind of stand-alone device): Print one out - batteries included.

And this is only the beginning. The resolution and geometries of screen processes is limited. With printing you can make structurs as fine as your print head (and ink) allow. And with batteries/capacitors (and sensors/actors) it's all about structure.
Tachyon8491
not rated yet Jun 19, 2013
I judge this a tremendous accomplishment - innovative and daring, an extension of existing technology that can possibly go even much further. It would now seem possible to 3-D print complete, working microminiaturised devices which include their power sources.
Mirar
not rated yet Jun 23, 2013
Interesting, but either I can't read or it's lacking a bit of facts.

Since when do we measure size as grainsize of sand? According to wikipedia, that would be 0.25 to 2mm. Judging from the image, I would say about 1.5mm including casing?

And how much can it store? Is it comparable to a 1.5mm^3 cube cutout of a packed litium battery in a cell phone, or better? Or worse? "Comparable" doesn't mean much more than it can store energy as well, so you can compare them?