{"id":49619,"date":"2017-10-30T05:56:19","date_gmt":"2017-10-30T05:56:19","guid":{"rendered":"https:\/\/www.biphoo.com\/bipnews\/?p=49619"},"modified":"2017-10-30T05:56:19","modified_gmt":"2017-10-30T05:56:19","slug":"huge-discovery-could-change-phones-forever","status":"publish","type":"post","link":"https:\/\/www.biphoo.com\/bipnews\/technology\/innovation\/huge-discovery-could-change-phones-forever.html","title":{"rendered":"Huge discovery could change phones forever"},"content":{"rendered":"

Huge discovery could change phones forever<\/span><\/strong><\/span><\/h2>\n

Huge discovery could change phones forever:- Scientists have just figured out why phones don’t last as long as they could, which could pave the way for longer lasting batteries.<\/span><\/p>\n

If you\u2019re frustrated by how short the battery life is on your iPhone or Android device, there\u2019s good news. Scientists have just figured out what is preventing us from making big advances on battery technology, which could hopefully help us overcome a tremendous roadblock in the way of the advancement of mobile technology.<\/span><\/p>\n

Scientists took atomic-level images of something called dendrites, which are finger-like growths that penetrate the barrier between battery compartments and cause them to fail. Dendrites limit the effectiveness of batteries, forcing us to charge our phones often.<\/span><\/p>\n

Scientists used cryo-electron microscopy (cryo-EM) to fire beams of electrons at some biomolecules that had been frozen, a technique that resulted in a Nobel Prize win for the scientists behind it. Using this knowledge, we may be able to design better batteries in the future.<\/span><\/p>\n

The full statement from the DOE\/SLAC National Accelerator Laboratory follows below.<\/span><\/p>\n

Scientists from Stanford University and the Department of Energy\u2019s SLAC National Accelerator Laboratory have captured the first atomic-level images of finger-like growths called dendrites that can pierce the barrier between battery compartments and trigger short circuits or fires. Dendrites and the problems they cause have been a stumbling block on the road to developing new types of batteries that store more energy so electric cars, cell phones, laptops and other devices can go longer between charges.<\/span><\/p>\n

This is the first study to examine the inner lives of batteries with cryo-electron microscopy, or cryo-EM, a technique whose ability to image delicate, flash-frozen proteins and other \u201cbiological machines\u201d in atomic detail was honored with the 2017 Nobel Prize in chemistry.<\/span><\/p>\n

The new images reveal that each lithium metal dendrite is a long, beautifully formed six-sided crystal \u2013 not the irregular, pitted shape depicted in previous electron microscope shots. The ability to see this level of detail for the first time with cryo-EM will give scientists a powerful tool for understanding how batteries and their components work at the most fundamental level and for investigating why high-energy batteries used in laptops, cell phones, airplanes and electric cars sometimes fail, the researchers said. They reported their findings in Science today.<\/span><\/p>\n

\u201cThis is super exciting and opens up amazing opportunities,\u201d said Yi Cui, a professor at SLAC and Stanford and investigator with the Stanford Institute for Materials and Energy Sciences (SIMES) whose group did the research.<\/span><\/p>\n

\u201cWith cryo-EM, you can look at a material that\u2019s fragile and chemically unstable and you can preserve its pristine state \u2013 what it looks like in a real battery \u00ad- and look at it under high resolution,\u201d he said. \u201cThis includes all kinds of battery materials. The lithium metal we studied here is just one example, but it\u2019s an exciting and very challenging one.\u201d<\/span><\/p>\n

Cui\u2019s lab is one of many developing strategies to prevent damage from dendrites, like adding chemicals to the electrolyte to keep them from growing or developing a \u201csmart\u201d battery that automatically shuts off when it senses that dendrites are invading the barrier between the battery\u2019s chambers.<\/span><\/p>\n

But until now, scientists have not been able to get atomic-scale images of dendrites or other sensitive battery parts. The method of choice \u2013 transmission electron microscopy, or TEM \u2013 was too harsh for many materials, including lithium metal.<\/span><\/p>\n

\u201cTEM sample preparation is carried out in air, but lithium metal corrodes very quickly in air,\u201d said Yuzhang Li, a Stanford graduate student who led the work with fellow grad student Yanbin Li. \u201cEvery time we tried to view lithium metal at high magnification with an electron microscope the electrons would drill holes in the dendrite or even melt it altogether.\u201d<\/span><\/p>\n

\u201cIt\u2019s like focusing sunlight onto a leaf with a magnifying glass. But if you cool the leaf at the same time you focus the light on it, the heat will be dissipated and the leaf will be unharmed. That\u2019s what we do with cryo-EM. When it comes to imaging these battery materials, the difference is very stark.\u201d<\/span><\/p>\n

Batteries Take a Freezing Dip<\/span><\/p>\n

In cryo-EM, samples are flash-frozen by dipping them into liquid nitrogen, then sliced for examination under the microscope. You can freeze a whole coin-cell battery at a particular point in its charge-discharge cycle, remove the component you\u2019re interested in and see what is happening inside that component at an atom-by-atom scale. You could even create a stop-action movie of battery activity by stringing together images made at different points in the cycle.<\/span><\/p>\n

For this study, the team used a cryo-EM instrument at Stanford School of Medicine to examine thousands of lithium metal dendrites that had been exposed to various electrolytes. They looked not only at the metal part of the dendrite, but also at a coating called SEI, or solid electrolyte interphase, that develops as the dendrite reacts with the surrounding electrolyte. This same coating also forms on metal electrodes as a battery charges and discharges, and controlling its growth and stability are crucial for efficient battery operation.<\/span><\/p>\n

They discovered, to their surprise, that the dendrites are crystalline, faceted nanowires that prefer to grow in certain directions. Some of them developed kinks as they grew, but their crystal structure remained surprisingly intact in spite of the kinks.<\/span><\/p>\n

Zooming in, they used a different technique to look at the way electrons bounced off the atoms in the dendrite, revealing the locations of individual atoms in both the crystal and its SEI coating. When they added a chemical commonly used to improve battery performance, the atomic structure of the SEI coating became more orderly, and they think this may help explain why the additive works.<\/span><\/p>\n

\u201cWe were really excited. This was the first time we were able to get such detailed images of a dendrite, and we also saw the nanostructure of the SEI layer for the first time,\u201d said Yanbin Li. \u201cThis tool can help us understand what different electrolytes do and why certain ones work better than others.\u201d<\/span><\/p>\n

Going forward, the researchers say they plan to focus on learning more about the chemistry and structure of the SEI layer.<\/span><\/p>\n

Researchers from the Stanford School of Medicine, ShanghaiTech University and University of Siegen also contributed to this work, which was supported by the DOE Office of Vehicle Technologies under the Battery Materials Research Program and Battery 500 Consortium.<\/span><\/p>\n

SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the U.S. Department of Energy Office of Science.<\/span><\/p>\n

SLAC National Accelerator Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.<\/span><\/p>\n

Source:-\u00a0http:\/\/www.babwnews.com\/2017\/10\/huge-discovery-could-change-phones-forever\/<\/span><\/p>\n

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