Electronic devices typically have to be manufactured with existing rectangular or cylindrical batteries in mind – but what product designs might be possible if that weren't the case? Scientists recently created proof-of-concept 3D-printed batteries, paving the way for practical batteries that could be made in any shape.

Working with colleagues from Texas State University, a team led by Duke University's Benjamin Wiley and Christopher Reyes made the lithium-ion batteries out of poly(lactic acid) (PLA), using an inexpensive 3D printer.

Ordinarily PLA wouldn't work for such a purpose, as it isn't an ionic conductor. To remedy this problem, the scientists boosted the polymer's conductivity by infusing it with an electrolyte solution consisting of ethyl methyl carbonate, propylene carbonate and lithium perchlorate. Additionally – in order to further increase conductivity – they utilized graphene in the battery's anode, and carbon nanotubes in its cathode, as opposed to more traditional materials such as graphite.

The team successfully 3D-printed a functioning coin cell battery, along with an integrated battery within an LED-equipped bracelet, the latter of which was able to keep the LED illuminated for about 60 seconds.

Although such performance isn't sufficient for practical use, the scientists are now researching approaches to increasing the batteries' capacity. These could include the use of purpose-made 3D-printable pastes, instead of the enhanced PLA.

A paper on the research was recently published in the journal ACS Applied Energy Materials.