Lithium-ion battery safety has been a hot topic in the scientific community in light of instances of the Samsung Galaxy Note 7 bursting into flames. In order to address these concerns, scientists must first better understand exactly what is causing these safety concerns. In order to do that, a team from the University of Michigan is looking inside the batteries and filming growing dendrites – something the researchers cite as one of the major problems for next-gen lithium batteries.
The study focused primarily on lithium-metal batteries, which have the potential to store 10 times more energy that current lithium-ion batteries. However, researchers believe that issues with dendrites cannot be amended, the future of the Li-metal battery will not be as limitless as some believe.
“As researchers try to cram more and more energy in the same amount of space, morphology problems like dendrites become major challenges. While we don’t fully know why the Note 7s exploded, dendrites make bad things like that happen,” said Kevin Wood, postdoctoral researcher and ECS student member. “If we want high energy density batteries in the future and don’t want them to explode, we need to solve the dendrite problem.”
The group caught dendrites in action by looking through a high-definition video microscope that they monitored to see both the dendrite growth and the voltage between the two electrodes. From this, the group could link voltage patterns to specific dendrite activity.
From the University of Michigan:
The researchers were able to see dendrites grow as lithium accumulated on the surface of an electrode, and shrink when the cycle reversed, pulling lithium away from the surface. They saw pits form in the electrode when the lithium was removed, and they saw how these pits became nucleation sites for dendrites on the next cycle.
“If you want to get to practical operating conditions, I don’t think there’s any way to truly prevent dendrite growth,” Wood says. “But by controlling dendrite growth you can enable batteries that have long lifetimes and better safety.”
