COUNCIL CHRONICLE – Cryo-EM or cryo-electron microscopy, the technology that just recently got awarded the 2017 Nobel Prize in Chemistry was put to good use by a new study’s team that now believes to know the reason behind high-power battery fires.
Cryo-EM Offered a New Perspectives at Dendrites and the Battery Fires They Provoke
The SLAC National Accelerator Laboratory from the Department of Justice and Stanford University scientists are behind this new study. Thanks to the use of cryo-EM, the specialists were able to capture the first-ever atomic-level images of dendrites. These are ‘finger-like’ growths that can seemingly pierce the barriers between the different layers of a battery. In doing so, they can also apparently start a fire.
The images reveal that each lithium metal dendrite is basically a long, six-sided crystal, a significant departure from the seemingly irregular shapes discovered by previous studies.
By establishing the exact structure of dendrites and their components, researchers are hoping to glean and gain a deeper understanding as to the way batteries function at their most fundamental level. It could also help determine why such high-energy batteries used in anything from smartphones to airplanes, for example, can sometimes fail.
The cryo-EM technology helped the team freeze their battery at any point they wanted it to in its charge-discharge cycle. It also allowed them to remove several of its components and also observe how it reacted at an atom-to-atom basis.
Although theories exist as to how dendrites forms, they were too delicate to study and until this latest technology, they were also almost impossible to see clearly. Thanks to the cryo-EM, scientists can now analyze them in never before seen details. They are hoping that, in doing so, they will be able to develop safer, better batteries.
The current study findings also helped find the spark that leads to battery fires. Apparently, dendrite growths can sometimes pierce through the separator, which might lead to a short circuit and this to a fire. The separator is the membrane that delimitates the cathode from the anode.
Its being pierced can cause a surge of current and subsequent thermal runaway. As the increased heat meets with the flammable electrolyte fluids, fires can get born.
Current study findings and a video detailing some of the results are available in a paper released in the journal Science.
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