Prototype magnesium battery operates at room temperature in breakthrough

Batteries as they stand today are dominated by lithium-ion battery types, where lithium ions move between the anode and cathode during charging and discharging cycles. Enormous research efforts continue to improve and perfect chemistries like lithium-iron-phosphate, alongside research into solid-state batteries that would replace flammable liquid electrolytes with solid ones, as well. And, sodium-based alternatives have advanced, as researchers continue to search for viable next-generation chemistries that are cheap, high-energy, and safe.

Magnesium has long been seen as a promising alternative chemistry. Like sodium, the element or metal is abundant, non-toxic, and theoretically capable of high volumetric energy density.

However, magnesium has had what chemists describe as “sluggish ion mobility” at room temperatures, meaning it has been a long way from practical use. (At very high and extreme temperatures, mobility increases, however this is generally interesting though not useful for many applications.)

Now a team at Tohoku University has now demonstrated a rechargeable magnesium battery that works at room temperature, using an amorphous oxide cathode with the formula Mg₀.₂₇Li₀.₀₉Ti₀.₁₁Mo₀.₂₂O. The cathode design, says the researchers, allows magnesium ions to diffuse more freely through an ion-exchange process between lithium and magnesium.

“The reason magnesium hasn’t been the main material used for batteries is because of a sluggish reaction that prevents room-temperature operation,” explained Tetsu Ichitsubo of Tohoku University. “Imagine if your device batteries could only function in extreme temperatures. It would be essentially useless for day-to-day life.”

The prototype delivered enough power to light a blue LED for 200 cycles, indicating reversible magnesium intercalation rather than side reactions, dubbed a common limitation in earlier trials. The system operated at about 2.5 V, demonstrating sufficient potential for external applications.

“We made a prototype full cell to test this battery in action, and found it was able to discharge sufficient amounts of energy even after 200 cycles,” said Ichitsubo. “It was enough to continuously power a blue light-emitting diode (LED).”

The team confirmed through chemical analysis that the capacity originated from genuine magnesium insertion. The result marks one of the first oxide cathodes to sustain magnesium-ion operation under ambient conditions.

The development remains in a laboratory demonstration environment, many steps away from a commercial application. But now the question of where magnesium could support new types of batteries, especially when facing limited resources, is open.