A new magnesium battery can charge, work at room temperature, and use common materials. Could this be the breakthrough that challenges lithium for energy storage?
Prototype coin-cell magnesium battery with the newly developed amorphous oxide cathode powering a blue light-emitting diode (LED). Since more than 2.5 volts are required to light the LED, this demonstrates that the battery generates sufficient voltage and can deliver power to an external circuit. Credit: Tomoya Kawaguchi
The need for large, sustainable energy storage is growing as technology advances. Lithium batteries dominate today, but lithium is scarce and hard to produce at scale. Magnesium, by contrast, is abundant in the Earth’s crust, offering a promising alternative for future batteries—if its technical challenges can be overcome.
Magnesium has not been widely used in batteries because its reactions are slow, preventing reliable operation at room temperature. Room-temperature performance is essential for magnesium-based energy storage to become a viable alternative and reduce reliance on limited lithium resources.
Researchers at Tohoku University have addressed this problem with a prototype rechargeable magnesium battery (RMB) that overcomes many of magnesium’s traditional limitations. Using a newly designed amorphous oxide cathode, the team achieved reversible magnesium insertion and extraction under ambient conditions. Previous magnesium batteries struggled with fast and reversible Mg-ion diffusion, limiting efficiency at room temperature. The amorphous oxide cathode solves this by employing an ion-exchange process between lithium and magnesium, creating diffusion pathways that allow Mg ions to move more easily.
A prototype full cell demonstrated stable energy discharge even after 200 cycles, enough to continuously power a blue LED. Earlier demonstrations of rechargeable magnesium batteries often showed negative discharge voltages, failing to deliver usable energy. Chemical analysis confirmed that the observed capacity originates from true magnesium intercalation, rather than side reactions, setting this work apart from prior systems.
This is the first reliable demonstration of an oxide cathode enabling magnesium battery operation under ambient conditions. It also establishes key design principles for next-generation cathode materials: creating structural free volume, controlling particle size at the nanoscale, and ensuring compatibility with advanced electrolytes.
These advances bring magnesium batteries closer to practical use as safe, sustainable, and resource-resilient energy storage systems.
