As technology advances, the demand for large-scale and sustainable energy storage also increases. To address this need, researchers at Tohoku University have developed a prototype rechargeable magnesium battery (RMB) that surmounts many of the persistent challenges faced by magnesium-based energy storage. This breakthrough represents a potential next stage in energy storage - a fast-charging battery made from sustainable materials.
Lithium is a scarce resource, which makes it difficult to produce enough lithium-ion batteries to keep up with new technology and our ever-expanding population. In comparison, magnesium can be found in abundance right under our feet: in the Earth's crust.
"The reason magnesium hasn't been the main material used for batteries is because of a sluggish reaction that prevents room-temperature operation," explains Tetsu Ichitsubo (Tohoku University), "Imagine if your device batteries could only function in extreme temperatures. It would be essentially useless for day-to-day life."
Therefore, achieving room temperature operation is a key to realizing magnesium-based energy storage as a competitive alternative that can reduce dependence on our limited lithium resources. Using a newly designed amorphous oxide cathode (Mg0.27Li0.09Ti0.11Mo0.22O), the research team successfully achieved this feat.
Previous magnesium batteries had issues achieving fast and reversible Mg-ion diffusion, which prevented them from operating efficiently at room temperature. However, the amorphous oxide cathode uses an ion-exchange process between lithium and magnesium that creates diffusion pathways that allow Mg ions to move more easily.
As a result, the cathode supports reversible magnesium insertion and extraction at room temperature.
"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," remarks Ichitsubo, "It was enough to continuously power a blue light-emitting diode (LED). This is exciting, because previous demonstrations of RMBs showed negative discharge voltages, which means they failed to deliver usable energy."
They investigated the underlying mechanism of this battery as well. The study confirms that the observed capacity originates from true magnesium intercalation, verified by rigorous chemical analysis. This distinguishes the system from previous reports where side reactions, rather than Mg-ion movement, dominated the apparent performance.
This work represents the first reliable demonstration of an oxide cathode enabling RMB operation under ambient conditions. It establishes fundamental design principles for next-generation cathode materials: introducing structural free volume, controlling particle size at the nanoscale, and ensuring compatibility with advanced electrolytes. Together, these advances bring RMBs closer to practical application as safe, sustainable, and resource-resilient energy storage systems.
The findings were published in Communications Materials on September 17, 2025.