Self-repairing batteries

UTokyo engineers develop a way to create high-capacity long-life batteries

May 16, 2019

Engineers at the University of Tokyo continually pioneer new ways to improve battery technology. Professor Atsuo Yamada and his team recently developed a material which could significantly extend the life of batteries and afford them higher capacities as well.

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If you could see inside a typical battery, you would see layers of metallic material. As batteries charge and discharge, these layers degrade and develop cracks or flakes — called stacking faults — which reduce the batteries’ ability to store and deliver charge. These stacking faults occur because the material is held together by a weak force called the Van der Waals force, which is easily overwhelmed by the stress put on the materials during charging and use.

Yamada and colleagues demonstrated that if the battery is made with a model material — oxygen redox-layered oxide (Na₂RuO₃ ) — then something remarkable happens. Not only does the degradation from charge and discharge cycles diminish, but the layers actually self-repair. This is because the material the researchers demonstrated is held fast by a force called coulombic attraction, which is far stronger than the Van der Waals force.

“This means batteries could have far longer life spans, but also they could be pushed beyond levels that currently damage them,” said Yamada. “Increasing the energy density of batteries is of paramount importance to realize electrified transportation.”

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