MSGID: 1:317/3 6466fb6d   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    An electric vehicle battery for all seasons    
    New electrolyte for lithium-ion batteries performs well in frigid regions   
   and seasons    
      
     Date:   
         May 18, 2023   
     Source:   
         DOE/Argonne National Laboratory   
     Summary:   
         Scientists have developed a fluorine-containing electrolyte for   
         lithium- ion batteries whose charging performance remains high   
         in frigid regions and seasons. They also determined why it is   
         so effective.   
      
      
         Facebook Twitter Pinterest LinkedIN Email   
      
   ==========================================================================   
   FULL STORY   
   ==========================================================================   
   Many owners of electric vehicles worry about how effective their battery   
   will be in very cold weather. Now a new battery chemistry may have solved   
   that problem.   
      
   In current lithium-ion batteries, the main problem lies in the liquid   
   electrolyte. This key battery component transfers charge-carrying   
   particles called ions between the battery's two electrodes, causing   
   the battery to charge and discharge. But the liquid begins to freeze at   
   sub-zero temperatures. This condition severely limits the effectiveness   
   of charging electric vehicles in cold regions and seasons.   
      
   To address that problem, a team of scientists from the U.S. Department   
   of Energy's (DOE) Argonne and Lawrence Berkeley national laboratories   
   developed a fluorine-containing electrolyte that performs well even in   
   sub-zero temperatures.   
      
   "Our team not only found an antifreeze electrolyte whose charging   
   performance does not decline at minus 4 degrees Fahrenheit, but we   
   also discovered, at the atomic level, what makes it so effective," said   
   Zhengcheng "John" Zhang, a senior chemist and group leader in Argonne's   
   Chemical Sciences and Engineering division.   
      
   This low-temperature electrolyte shows promise of working for batteries   
   in electric vehicles, as well as in energy storage for electric grids   
   and consumer electronics like computers and phones.   
      
   In today's lithium-ion batteries, the electrolyte is a mixture of a widely   
   available salt (lithium hexafluorophosphate) and carbonate solvents such   
   as ethylene carbonate. The solvents dissolve the salt to form a liquid.   
      
   When a battery is charged, the liquid electrolyte shuttles lithium   
   ions from the cathode (a lithium-containing oxide) to the anode   
   (graphite). These ions migrate out of the cathode, then pass through the   
   electrolyte on the way into the anode. While being transported through   
   the electrolyte, they sit at the center of clusters of four or five   
   solvent molecules.   
      
   During the initial few charges, these clusters strike the anode surface   
   and form a protective layer called the solid-electrolyte interphase. Once   
   formed, this layer acts like a filter. It allows only the lithium ions to   
   pass through the layer while blocking the solvent molecules. In this way,   
   the anode is able to store lithium atoms in the structure of the graphite   
   on charge. Upon discharge, electrochemical reactions release electrons   
   from the lithium that generate electricity that can power vehicles.   
      
   The problem is that in cold temperatures, the electrolyte with carbonate   
   solvents begins to freeze. As a result, it loses the ability to transport   
   lithium ions into the anode on charge. This is because the lithium ions   
   are so tightly bound within the solvent clusters. Hence, these ions   
   require much higher energy to evacuate their clusters and penetrate the   
   interface layer than at room temperature. For that reason, scientists   
   have been searching for a better solvent.   
      
   The team investigated several fluorine-containing solvents. They were   
   able to identify the composition that had the lowest energy barrier for   
   releasing lithium ions from the clusters at sub-zero temperature. They   
   also determined at the atomic scale why that particular composition worked   
   so well. It depended on the position of the fluorine atoms within each   
   solvent molecule and their number.   
      
   In testing with laboratory cells, the team's fluorinated electrolyte   
   retained stable energy storage capacity for 400 charge-discharge cycles   
   at minus 4 F.   
      
   Even at that sub-zero temperature, the capacity was equivalent to   
   that of a cell with a conventional carbonate-based electrolyte at room   
   temperature.   
      
   "Our research thus demonstrated how to tailor the atomic structure   
   of electrolyte solvents to design new electrolytes for sub-zero   
   temperatures," Zhang said.   
      
   The antifreeze electrolyte has a bonus property. It is much safer than   
   the carbonate-based electrolytes that are currently used, since it will   
   not catch fire.   
      
   "We are patenting our low-temperature and safer electrolyte and are now   
   searching for an industrial partner to adapt it to one of their designs   
   for lithium-ion batteries," Zhang said.   
      
   This research appears in Advanced Energy Materials. In addition to John   
   Zhang, Argonne authors are Dong-Joo Yoo, Qian Liu and Minkyu Kim. Berkeley   
   Lab authors are Orion Cohen and Kristin Persson.   
      
   This work was funded by the DOE Office of Energy Efficiency and Renewable   
   Energy, Vehicle Technologies Office.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Batteries # Fuel_Cells # Energy_and_Resources #   
                   Energy_Technology # Electricity # Alternative_Fuels #   
                   Chemistry # Nature_of_Water   
       * RELATED_TERMS   
             o Lithium o Battery_(electricity) o Fluorine o Acid o Wood o   
             Mass_spectrometry o Sports o Chelation   
      
   ==========================================================================   
   Story Source: Materials provided by   
   DOE/Argonne_National_Laboratory. Original written by Joseph   
   E. Harmon. Note: Content may be edited for style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Dong‐Joo Yoo, Qian Liu, Orion Cohen, Minkyu Kim, Kristin A.   
      
         Persson, Zhengcheng Zhang. Rational Design of Fluorinated   
         Electrolytes for Low Temperature Lithium‐Ion   
         Batteries. Advanced Energy Materials, 2023; DOI:   
         10.1002/aenm.202204182   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/05/230518120853.htm   
      
   --- up 1 year, 11 weeks, 3 days, 10 hours, 50 minutes   
    * Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)   
   SEEN-BY: 15/0 106/201 114/705 123/120 153/7715 218/700 226/30 227/114   
   SEEN-BY: 229/110 112 113 307 317 400 426 428 470 664 700 292/854 298/25   
   SEEN-BY: 305/3 317/3 320/219 396/45   
   PATH: 317/3 229/426