Posted by Garrett Moran
A recent article from ScienceDaily illustrates a group of engineers from Columbia University School of Engineering discovering a way to make the common lithium metal batteries not only safer, but also more efficient and longer lasting. There are countless stories of lithium batteries catching on fire and exploding. This is due to the formation of microstructures that contain non-conductive compounds on the surface of lithium metal during the battery use or recharge cycle. These undesirable microstructures stop the lithium ion transport process and cause dangerous short-circuiting within the battery which results in the battery overheating and either catching on fire or exploding.
The group of engineers discovered that the addition of alkali metals, such as potassium ions to a conventional lithium battery electrolyte, prevents lithium microstructure proliferation during the batteries use. The group achieved this by using a combination of techniques to examine the lithium metal while the additives were introduced. These techniques include microscopy, nuclear magnetic resonance and computational modeling. The article notes that when the metal was being examined while the additives were being introduced, “unique chemistry” was observed at the lithium/electrolyte interface. This unique chemistry was not specified, but the teams PI says that this addition of potassium salt to the lithium electrolyte mitigates the formation of these undesirable, non-conductive microstructures. The article also notes that this discovery differs in technique from traditional electrolyte manipulation approaches where depositing conductive polymers on the lithium metal surface was the primary focus. This discovery is one of the first to characterize the surface chemistry of lithium metal using NMR and is considered a breakthrough for new techniques using NMR and future designs of electrolytes for lithium metal.
Your title is sure to attract attention because everyone is aware of safety precautions we all are required to take when traveling with Li batteries, for example. Your summary brings out the two points of the article. First that a way to render the batteries safer has been discovered. Although it is not clear when this unique chemistry might actually be used in commercial batteries. The other point is that the discovery involved the use of NMR, a technique obscure to most people. It is useful, however, to point out that such obscurities that chemists use and study really have an impact on our lives. There is not much of a clue in your summary as to how NMR is used. I think it is C13 NMR on organic polymers at the surfaces of the electrode that is used, not some kind of NMR on metal nuclei.
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