Fuel cells typically run out and need extra juicing up to run again. But this one fuel cell on the other hand, can keep going on even after it runs out of fuel.
The new solid oxide fuel cell (SOFC) was developed at Harvard and it converts hydrogen into electricity. Along the way, it also creates energy it can store away like a battery. Researcher Shriram Ramanathan explains:
"This thin-film SOFC takes advantage of recent advances in low-temperature operation to incorporate a new and more versatile material. Vanadium oxide (VOx) at the anode behaves as a multifunctional material, allowing the fuel cell to both generate and store energy."
The tiny fuel cell pictured next to the battery can keep on going for 3.5 minutes at a current density of 0.2 mA/cm2 after it runs out of fuel. The fuel cell pumps out power comparably to other platinum anode SOFCs but the inclusion of VOx sets up extra chemical reactions within the device that keep producing energy when the fuel runs out.
"There are three reactions that potentially take place within the cell due to this vanadium oxide anode. The first is the oxidation of vanadium ions, which we verified through XPS (X-ray photoelectron spectroscopy). The second is the storage of hydrogen within the VOx crystal lattice, which is gradually released and oxidized at the anode. And the third phenomenon we might see is that the concentration of oxygen ions differs from the anode to the cathode, so we may also have oxygen anions being oxidized, as in a concentration cell."
The result is regardless more electrons pumped into the circuit. The finding was published in Nano Letters, and it's obviously a step up in fuel cell technology since after all this time, it's never had an actual improvement that could be used in implementation in devices.[Nano Letters via Harvard]