Researchers use 3D printing to create Li-ion battery the size of 'a grain of sand'

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Lithium-ion microbatteries the size of a grain of sand have been created by a team from Harvard University and the University of Illinois at Urbana-Champaign.

The microbatteries comprise precisely interlaced stacks of tiny battery electrodes. "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, Professor of Biologically Inspired Engineering at Harvard's School of Engineering and Applied Sciences. In recent years, engineers have invented many miniaturised devices, but the batteries that power them are as large or larger than the devices themselves. To solve the problem, the researchers turned to 3D printing, applying a broad range of specially formulated functional inks to create precise structures with the appropriate electronic, optical, mechanical or biological properties. To print 3D electrodes, Prof Lewis' group created an ink for the anode from nanoparticles of a 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 an interlaced stack of anodes and cathodes. The electrodes were then packaged into a tiny container, which was filled with an electrolyte solution.