Scientists unveil novel material for magnesium batteries

Researchers at Tohoku University have developed a novel cathode material for rechargeable magnesium batteries (RMBs) that enables efficient charging and discharging, even at low temperatures. This new material leverages an enhancing rock salt structure and could support the development of energy storage solutions that are safer and higher in capacity.

The study shows a significant improvement in magnesium (Mg) diffusion within a rock salt structure, a notable advancement since the denseness of atoms in this configuration had previously impeded Mg migration. By introducing a mixture of seven different metallic elements, the researchers created a crystal structure abundant in stable cation vacancies, facilitating easier Mg insertion and extraction. The high entropy strategy utilised by the researchers allowed the cation defects to activate the rock salt oxide cathode.

This development also addresses a limitation of RMBs — the difficulty of Mg transport within solid materials. Until now, high temperatures were required to enhance Mg mobility in conventional cathode materials, such as those with a spinel structure. Now, the novel material developed by Tohoku University operates efficiently at 90°C, demonstrating a reduction in the required operating temperature.

Tomoya Kawaguchi, a professor at Tohoku University, said that although lithium is scarce and unevenly distributed, magnesium is abundantly available and offers a more sustainable alternative for lithium-ion batteries. “Magnesium batteries, featuring the newly developed cathode material, are poised to play a pivotal role in various applications, including grid storage, electric vehicles and portable electronic devices, contributing to the global shift towards renewable energy and reduced carbon footprints,” Kawaguchi said.

Tetsu Ichitsubo, a professor at Tohoku University, said that this research harnesses the intrinsic benefits of magnesium, thereby overcoming previous limitations and paving the way for the next generation of batteries. Ultimately the development marks a step forward in the quest for efficient, eco-friendly energy storage solutions.

The research findings have been published in the Journal of Materials Chemistry A.

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