Chemical Engineers Build World's Smallest Fuel Cell

US chemical engineers have built the world’s smallest fuel cell, clocking in at only 9 cubic millimeters. While the hydrogen-fueled cell is currently a prototype, it could one day replace batteries in portable electronics.

Engineers at the University of Illinois at Urbana-Champaign created the cell using 4 components: a water reservoir, a chamber containing metal-hydride, a thin membrane separating the two, and an assembly of electrodes. The device’s water flow is conducted by surface tension— so it will work even if moved and rotated.

Small holes in the membrane let the water molecules reach the chamber as vapor. The vapor then reacts with the metal hydride to form hydrogen, which fills the chamber, pushes the membrane up, and blocks the flow of water.

As the hydrogen is depleted, more water enters the chamber to keep the reaction going.

The bite-sized cell currently generates 0.7 volts and a current of 0.1 milliamps for 30 hours before fuel runs out. That’s only enough power for microrobots and simple electronic systems, but future versions may be able to power cell phones.

Photo Credit: Saeed Moghaddam