ExtremeTech readers know by now that new battery tech is always promising and perpetually just over the horizon, but never quite seems to be attainable. Harvard just added to that field by 3D printing a lithium-ion microbattery that could be used to power devices in a number of markets, such as medicine.

As phones and other consumer devices are getting bigger, a microbattery may seem like a silly prospect for the consumer market, but a host of other equipment could greatly benefit from tiny batteries. Minuscule sensors on wearable computers — such as Google’s Glass — could benefit from even smaller batteries providing them with power. Small medical implants could become a more feasible solution to ailments if they can maintain power through the use of microbatteries, rather than using batteries that are roughly the size of the implants themselves.

In order to make a battery so small, the Harvard and University of Illinois at Urbana-Champaign team used a 3D printer to create tiny stacks of battery electrodes. Each electrode is thinner than a strand of human hair. The battery is of the standard lithium-ion variety, so with it comes all of the faults and benefits of lithium-ion, rather than a new source extended power.

The custom 3D printer employed by the team uses special inks that are electrochemically active, and harden into cathodes and anodes once extruded from the printer’s nozzle. The anodes and cathodes were printed in a pattern similar to a common comb, then a case and electrolyte solution were added as finishing touches. The overall battery measures in at a width of less than one millimeter.

In the above video, you can plainly see the 3D printer’s nozzle methodically building the battery layer-by-layer, and quite quickly as well, demonstrating that mass production may not be too difficult.

As for performance, the team claims that the 3D-printed microbatteries are comparable to the larger lithium-ions in our devices, but in terms of scale. The discharge and recharge rates are proportionally similar, as well as the batteries’ energy density and life cycle. Since the microbattery is similar in terms of scale but isn’t on the same scale as, for example, the battery in your phone, it doesn’t last nearly as long or provide as much power. However, if scaled up to the size of your phone, it’d seemingly provide a similar service to your phone’s current battery.

For now, though — like most amazing improvements in the field of battery tech — there’s no word on when this 3D-printed microbattery might hit the market, or be incorporated into some kind of consumer device.

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Research paper: doi: 10.1002/adma.201301036 – “3D Printing of Interdigitated Li-Ion Microbattery Architectures”