The group also reported that not all dendrites caused serious damage to the battery. Some actually broke off the electrode mid-cycle, and became “dead lithium” floating around the battery. In terms of the physicality of the dendrites, the team described them as rather organic-much like plants growing and withering over the course of the battery’s cycle. They also saw pits from in the actual electrode when the lithium was removed, and saw how these pits wound up becoming nucleation sites for dendrites on the next cycle. The team reports that dendrites grew as lithium accumulated on the surface of an electrode it would shrink when the cycle reversed, as the lithium was being pulled away from the surface. “It can be reproduced in any lab with an optical microscope, simple electrochemical equipment, a machine shop and a $100 budget.” “Our window battery is a simple platform that can be used by researchers worldwide,” Dasgupta said. From their observations, the team believes they now understand why dendrites grow in next-gen lithium metal batteries. From there, they were able to link voltage patterns to specific dendrite activity.įor what it’s worth, a battery with two lithium electrodes was used, a decision meant to avoid complicating the study by incorporating a different electrode, as it likely would’ve come with its own problems. This allows the team to observe the electrode and record whether dendrites grew or shrunk, and the general state of degradation as it relates to the voltage measurements. The aforementioned “window” they created is outfitted with a high-definition video microscope and wired for easy monitoring of the dendrite growth and the voltage between the two electrodes (which changes during charge and discharge cycles). With the Michigan approach, the team is hoping to understand not only how they grow, but why they’re growing. After its run its course, an autopsy would be performed to understand what physical changes took place inside.
The latter bunch would focus on electromechanical measurements while the battery is in operation. The Michigan team is taking a different approach to understanding dendrites than other research groups have in the past. “If we want high energy density batteries in the future and don't want them to explode, we need to solve the dendrite problem.” While we don't fully know why the Note 7s exploded, dendrites make bad things like that happen,” said Kevin Wood, a postdoctoral researcher in mechanical engineering who helped develop the battery window. “As researchers try to cram more and more energy in the same amount of space, morphology problems like dendrites become major challenges. But these batteries and their lithium-ion counterparts are very similar to one another, which has led to many speculating that dendrites could be the cause behind the recent problems Samsung’s been having with its phones. The reason why it hasn’t been in the news is due to the fact that lithium metal batteries aren’t available on the market (yet). Some dendrites have even grown so fast and rigid that they’ve actually wound up piercing the membrane between the electrodes this, in turn, shorted the lithium metal battery, and in some instances, led to spontaneous combustion. When they grow in the battery, it leads to a significant reduction in performance, while simultaneously raising safety concerns and cutting short the battery’s lifespan. What’s already known about dendrites is based on studies of lithium metal batteries - a power source that got its name because they have all-metal electrodes. They’re hoping that over the course of their observation and study, they’ll be able to publish a better understanding on dendrites, from which combat solutions can be developed. They recently cut open a next-generation lithium battery (different from the lithium-ion power sources currently used in consumer products), and created a window through which to spy on the development and growth of the lithium strands.
Dendrite facts how to#
Understanding dendrites and how to combat them is a relatively new field of study, and one that researchers at the University of Michigan have taken a keen interest in. And those familiar with this technology have begun suggesting the battery might have a dendrite problem.įor those unfamiliar, dendrites are basically whiskers of lithium that grow inside batteries, and can cause the devices they’re powering to lost power more quickly, short out, or in some instances, catch fire. While the reason why Samsung Galaxy Note 7s have been catching fire has yet to be confirmed, the focus is on the device’s lithium-ion batteries.
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