Understanding fluorine-free electrolytes via small-angle X-ray scattering

Scientific Achievement

We compare the solvation phenomenon of sodium tetraphenylborate (NaBPh4) salt dissolved in organic solvents of propylene carbonate (PC), 1,2-dimethoxyethane (DME), acetonitrile (ACN) and tetrahydrofuran (THF) by SAXS/WAXS measurement and MD simulation.

Significance and Impact

Fluorine-free electrolytes have attracted great attention because of its low-cost and environmental friendliness. However, so far, little is known about the solution structures of these electrolytes. This work emphasizes the importance of global and local structural analysis of fluorine-free sodium electrolytes, which will provide valuable clues for understanding the structure-performance relationship of electrolytes.

Research Detail

  • A unique structural feature is found in this salt-concentrated PC electrolyte by SAXS. Two characteristic peaks at 0.4 and 0.76 Å-1 emerged in concentrated NaBPh4/PC solution while only one peak at ~0.76 Å-1 can be found in NaBPh4 solutions using other solvents such as DME, ACN, and THF.
  • This two-peak phenomenon is mainly caused by the short-range stacking between bulky BPh4- anions (clusters). The distances between clusters contribute to the unique peak at ~0.4 Å-1.
  • Raman spectroscopy and MD simulations further confirm that there is a large population of CIPs in the concentrated NaBPh4/PC electrolyte.

Download this highlight 

DOI: 10.1016/j.jechem.2022.02.043  

Latest Updates

See All
  • JCESR Spotlight: Bob Jin Kwon, A Postdoc with Passion and Perseverance

    Argonne recognizes Kwon’s contributions to battery science with the Postdoctoral Performance Award. Article authored by: Michael Matz, Argonne Associate Bob Jin Kwon likes a good challenge, particularly when it comes to developing completely new kinds of batteries. “Developing new battery technologies is very challenging,” said … Read More

  • JCESR Spotlight: Lily Robertson Recognized for Her Contributions to Battery Research

    Argonne’s Postdoctoral Performance Award recognizes scientific achievements, leadership, and collaboration. Article authored by: Michael Matz, Argonne Associate Since her early days growing up in the Pacific Northwest, Lily Robertson has always wanted to help make the world a better place. “For as … Read More

  • Understanding fluorine-free electrolytes via small-angle X-ray scattering

    We compare the solvation phenomenon of sodium tetraphenylborate (NaBPh4) salt dissolved in organic solvents of propylene carbonate (PC), 1,2-dimethoxyethane (DME), acetonitrile (ACN) and tetrahydrofuran (THF) by SAXS/WAXS measurement and MD simulation. Read More

  • Navigating the Minefield of Battery Literature

    This is an invited perspective aiming to help researchers new to the field of battery research to circumvent certain recurring misconceptions and inaccuracies in the current battery literature. It covers the electrolyte ideality and practical situation in batteries, the difficulty in accurately determining ion transference … Read More

  • Quantifying Lithium Ion Exchange in Solid Electrolyte Interphase (SEI) on Graphite Anode Surfaces

    By using Li isotopic labelling of SEIs and electrolytes followed by time-of-flight secondary-ion mass spectroscopy and solid-state NMR analyses, we found that the majority of Li+ “immobilized” in the chemical ingredients were exchanged after 1 SEI formation cycle. Ion exchange by diffusion based on concentration … Read More