Researchers at Harvard University and the University of Illinois at Urbana-Champaign have 3D printed Lithium-Ion microbatteries which are the size of a grain of sand. These tiny batteries could provide power to micro-devices for use in medicine and communications or for any miniaturized device where a tiny battery is needed.
The battery consists of stacks of 3D printed battery electrodes, each less than the width of a human hair. To provide adequate energy in such a small package the scientists had to produce ultra-thin anodes and cathodes in a tightly interlaced matrix.
Special inks were designed, with specific electrical and chemical properties, and then built a 3D printer which was able to create the precise structures for the battery.
These special inks have to function as electrochemically active materials for the anodes and cathodes and also harder quickly into stable layers on a microscopic scale.
To fulfill these design requirements the researchers created an ink for the cathode with nanoparticles of one lithium metal oxide compound, and an ink for the anode from nonoparticles of another. The 3D printer deposits these inks onto the teeth of two gold combs, which creates a tightly interlaced stack of anodes and cathodes.
“The innovative microbattery ink designs dramatically expand the practical uses of 3D printing, and simultaneously open up entirely new possibilities for miniaturisation of all types of devices, both medical and non-medical. It’s tremendously exciting,” said Wyss Founding Director Donald Ingber.
The team tested the battery’s to see how much energy can packed into them, how much power they can deliver and how long the charge held.The testing found that the electrochemical performance is on par with commercial batteries in terms of charge and discharge rate, cycle life and energy densities but in a much smaller scale.
The results of the research was published in the online edition of Advanced Materials and the project was supported by the National Science Foundation and the DOE Energy Frontier Research Center on Light-Material Interactions in Energy Conversion.