Scientists use 3D printer to create microbatteries smaller than a single GRAIN of sand, paving the way for high-powered flying robot insects and mini medical implants

The revolutionary technology behind 3D-printed car parts, food and guns can also be used to print batteries smallerthan a grain of sand. Scientists have used a 3D printer to make linthium-ion microbatteries that can fit into tiny devices that had previously stumped engineerslooking to power them for longer periods. The batteries were constructed from interlaced stacks of tiny battery electrodes, which conduct electricity, that are each smaller than the width of a single human hair.Scientists from Harvard University and the University of Illinois at Urbana-Champaign reported the results of their efforts in the journal Advanced Materials. '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 the seniorauthor of the study, Jennifer A Lewis, according to a press release by Harvard's Wyss Institute for Biologically Inspired Engineering, where Lewis is a professor.Many engineers have developed miniaturized electronic devices, such as miniscule medical implants, insect-like flying robots and audio and visual recorders that can fit on a pair of glasses. The batteries normally used to power such gadgets were too large, so manufacturers would use ultra-thin films of solid materials to build the electrodes. But these didn't provide enough power. Lewis and her colleagues realized they could pack more energy on a small scale if theycould create stacks of interlaced, ultra-thin electrodes built from plane. They knew 3D printing would allow them to precisely build the battery. The team expanded on the functional 'inks' the printer uses, designing some with useful chemical and electrical properties. The inks Lewis' group createdhad to function as electrochemically active materials, while also being capable of exiting a 3D printer's fine nozzle and hardening in its final form. The ink they developed for the anode part of the battery--or the 'negative' side in a Duracell--is made with nanoparticles of one lithium metal oxide compound. Ink for the cathode--the 'positive' side--was made from another compound.