Lithium-based batteries have been restricted by the limited availability of cobalt. More than 50% of all cobalt produced globally is used in energy storage devices. A majority of that is mined in the Republic of Congo, oftentimes by children.
Lithium-based energy storage technology relies on cobalt because of the metal’s ability to accommodate ions and remain stable as ions move in and out.
Inside batteries, lithium ions shift between two electrodes, an anode and a cathode. The cathode’s layered structure allows it to intercalate the lithium ions and store them. Cobalt is one of the few elements that won’t migrate to fill the void left when lithium ions are pulled from the cathode to the anode as the battery charges. Therefore, it ensures the integrity of this layered construction.
In an effort to solve the resource limitation dilemma, Gerberand Ceder, professor in the Department of Materials Science and Engineering at University of California, Berkeley, and his team of researchers began disordering cathodes rather than designing them with the traditional layered structure. This enabled them to employ other materials.
Ceder’s team pioneered a concept called disordered rock salts in 2014 that enables cathodes to maintain a high energy density without a striated structure. The team’s latest study, published in Nature last week, shows how manganese, a cheaper, highly available element can work within this concept.
The technology requires further testing and scaling, but researchers have opened new possibilities for the design of cathodes, a discovery that may have tremendous industry-wide implications for energy storage technologies.
“You can pretty much use any element in the periodic table now because we’ve shown that cathodes don’t have to be layered,” Ceder said in a statement. “Suddenly we have a lot more chemical freedom, and I think that’s where the real excitement is because now we can do exploration of new cathodes.”
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