Solid-state EV batteries without expensive lithium made possible by magnesium conductivity breakthrough
Researchers from the Tokyo University of Science have cracked the code of using plentiful magnesium instead of expensive lithium in the next generation of solid-state electric vehicle batteries. The decades-long magnesium conductivity hurdle before replacing lithium as a solid-state battery material has been overcome by adding organic materials and an accelerator. Junior Associate Professor Masaaki Sadakiyo explains the breakthrough as follows:
In this work, we exploited a class of materials called metal-organic frameworks (MOFs). MOFs have highly porous crystal structures, which provide the space for efficient migration of the included ions. Here, we additionally introduced a "guest molecule," acetonitrile, into the pores of the MOF, which succeeded in strongly accelerating the conductivity of Mg2+.
As a result, the typically low level of magnesium ions' conductivity in solid materials at room temperature, has been greatly increased to reach the 10-3 S cm-1 threshold required for tangible application in solid-state batteries.
This superconductivity of magnesium ions may have thus hit a record, but it is the minimum required for practical solid-state battery production, so the team of Japanese scientists is now focused on improving the conductivity level of the new magnesium-based material even further.
Unlike lithium, magnesium is not considered a rare earth material and is abundant in the earth's crust. Moreover, Elon Musk recently urged lithium mining companies like the Australian ones to go into refining, too, as a "license to print money," since battery-grade lithium refiners are few and far between and most of them are located in China.
Swapping lithium for magnesium in solid-state batteries will allow electric car makers to escape the near-monopoly of Chinese lithium refiners, as well as significantly lower the per-unit cell cost of the promising technology.
Solid-state batteries have many advantages before the current chemistries, mainly in terms of safety and durability, so any breakthrough research that makes them easier and cheaper to make is welcome news for both the major electric vehicle makers, and their future customers.