Rechargeable iron-based batteries use iron metal as their key active material in their electrodes. Working examples include iron-air electrochemical batteries and iron flow batteries, although there are more types. Scientists at Stanford University and their colleagues have tapped more energy out of iron-based batteries, using a novel iron-based cathode material.
Scientists Unlock More Energy In Dense Battery Cathodes
Battery cathodes are positive battery electrodes, where reduction occurs during discharge. They accept electrons, and typically contain metal oxides or similar compounds that store and release ions.
The Stanford team developed a novel, iron-based cathode material for battery energy storage. This achieved a capacity increase that was previously believed impossible.
The cathode material delivered more energy in iron-based batteries than ever before. It was able to donate and accept five electrons at a time instead of the usual two or three. That’s a phenomenal increase!
A Great Advance For Lithium-Ion Batteries
Iron’s abundant availability makes it an attractive substitute for cobalt and nickel. However, to date, lithium-ion batteries with iron-based cathodes have delivered disappointingly low voltages.
The Stanford discovery could do more than deliver powerful iron-based cathodes. It could also contribute to more powerful iron flow batteries, improved magnetic resonance imaging machines, magnetic levitation trains, and even superconductors.
This discovery comes on the back of previous research at Stanford University, dating from 2018. However, the stumbling block to optimizing iron metal continued to be the lack of a working model that proved the idea was practical.
The Best of Both Worlds Taps More Energy From Iron
Twenty three scientists from three U.S. universities, four U.S. national laboratories, plus universities in Japan and South Korea worked together to achieve this goal, that had defied others for so long.
The core problem has always been the way the cathode’s crystal structure collapses during charging. The researchers wondered whether making the particles extremely small, would extract more energy in longer-lasting iron-based batteries.
They ‘grew’ their crystals out of a ‘carefully conducted liquid’. This tweak, quite incredibly, allowed the iron ‘to reversibly give up, and later take back five electrons while the crystal structure remained stable.’
“A high-voltage, iron-based cathode could avoid the trade-off between higher voltage and higher-cost metals,” a team member explains. In other words, they achieved the best of both worlds. That’s amazing!
More Information
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Eighty-Five Megawatt Iron-Air Battery
Preview Image: A Banded Iron Formation
