Batteries the size of a grain of sand could soon be powering our medical implants and autonomous micro-robots, thanks to a development by scientists at Harvard and the University of Illinois. The batteries were created using a custom-made 3D printer with special inks.

The inks have just the right electrochemical properties that let them immediately harden as soon as they leave the printer. The 3D printed Li-Ion microbatteries are comparable to conventional batteries in their life expectancy, energy density, and charge and discharge rates. The team’s amazing invention is detailed in their paper, published in Advanced Materials.