Made of an interlacing series of electrodes, and thinner than a human hair, the new batteries could be used in medical implants and other devices that require extremely small batteries. "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 Harvard Professor Jennifer Lewis.
In most traditional miniature battery technologies, thin films of materials are used to build electrodes. The main problem with this method is that thin materials aren’t able to carry a lot of power. To resolve this issue Lewis and her group turned to 3D printing and designed a range of inks that have both the chemical and electrical properties needed to create the tightly interlocked geometry required by their batteries.
One of Lewis’ most difficult obstacles in creating her inks was building a material that could be extruded from an extremely small nozzle and then harden immediately to create an accurate shape. To overcome this issue, the team designed an ink for the battery’s anode that was made of a lithium metal oxide compound, while also creating a separate nanoparticle ink for the cathode.
Lewis’ specially designed 3D printer then took the inks and deposited them onto the teeth of two miniature gold combs. To complete the battery, the two interlocked meshes were packed in a small container which was filled with an electrolyte solution.
According to Shen Dillon, a member of Lewis’ team, "The electrochemical performance [of Lewis’ battery] is comparable to commercial batteries in terms of charge and discharge rate, cycle life and energy densities.”
In the future many miniature devices may owe their very existence to the work that Lewis and her team have completed.
Watch a Video of the Battery Being Printed:
Images and Video Courtesy of Harvard University