Scientists at the U.S. Joint Center for Energy Storage Research (JCESR) (Lemont, Illinois, USA) discovered a faster magnesium-ion solid-state conductor that could lead to solid-state magnesium-ion batteries that are energy dense and safe.
The electrolyte, which carries a charge between the battery’s cathode and anode, is a liquid in commercial batteries. This makes them potentially flammable, especially with lithium-ion. A solid-state conductor, which could become an electrolyte, would be more fire resistant.
The researchers began working on a magnesium battery, which offers higher energy density than lithium. However, they were stymied by a lack of options for a liquid electrolyte, most of which are corrosive to other battery parts.
“Magnesium is such a new technology, it doesn’t have any good liquid electrolytes,” says Gerbrand Ceder, a senior faculty specialist at Lawrence Berkeley National Laboratory (Berkeley, California, USA) and a project contributor. “We thought, why not leapfrog and make a solid-state electrolyte?”
The resulting magnesium scandium selenide spinel material has magnesium mobility comparable to solid-state electrolytes, the researchers say. Using nuclear magnetic resonance spectroscopy, their tests showed that magnesium ions could move through the material as rapidly as theoretical studies had predicted.
“This probably has a long way to go before you can make a battery out of it, but it’s the first demonstration that you can make solid-state materials with really good magnesium mobility through it,” Ceder says.
The tests did reveal a small amount of electron leakage, which must be removed before it can be used as a battery, he notes.
Source: Berkeley Lab, www.lbl.gov.