The smallest hydrogen fuel cell of just 3mm diameter was created by US chemical scientists and could replace batteries in portable electronics devices. Nowadays, batteries are used at a larger scale because they are very easy to make. This is in detriment of fuel cells even if they can store a higher amount of energy in the same space.In the beginning, pumps, pressure sensors and the control electronics of a fuel cell were not easy to make and as well the energy used by the pumps was higher than the one generated.
Saeed Moghaddam and Mark Shannon designed a fuel cell out of only 4 parts (thin membrane that separates a water reservoir above a chamber that contains metal hydride below, beneath the metal chamber is an assembly of electrodes) that can generate more power than it consumes.
Water molecules flow through very small holes in the membrane reaching the chamber that contains metal hydride. This reacts with water forming hydrogen, which by filling the chamber blocks the flow of water. Hydrogen reacts at the electrodes creating a flow of electricity. If hydrogen pressure drops, water can reenter in the chamber and the reaction is remade. Water flows into the chamber because of tension and not because of gravity, making the system able to rotate and still be able to function in normal parameters. This is perfect for portable electronics devices. Below is a picture showing how the cell works.
The newest cells give around 1mA current at around 1mV tension. This is not enough for larger consumers, like cell phones, but for sure the current will be higher with the next revisions of the cells. This new energy cell will revolutionize the electronics industry, cell phones, all kind of gadgets and portable devices.
Steve Arscott at the University of Lille in France, has designed a fuel cell that uses methanol as a hydrogen source instead of metal hydride. This cell has 3 times the volume of the micro fuel cell, and outputs a energy of 12,5mW/ cm2 much more higher than the micro fuel cell. The disadvantage is that the fuel cells need to be fed by an external fuel supply while the new device has the fuel internally.