Detection of the Order-to-Disorder Transition in Block Copolymer Electrolytes Using Quadrupolar <sup>7</sup>Li NMR Splitting

ORAL

Abstract

Mixtures of block copolymers and salts have been studied for use as safe electrolytes for batteries with energy-dense lithium metal anodes. Locating the order-to-disorder transition (ODT) in these systems is important, because microscopic morphology has a profound impact on bulk properties including ionic conductivity and mechanical rigidity. In this study, the ordered morphologies in a series of mixtures of polystyrene-b-poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt are shown to be aligned due to exposure to the magnetic field in an NMR instrument, which is confirmed using small-angle X-ray scattering (SAXS). This alignment results in quadrupolar triplet peak splitting in 7Li NMR, which disappears above the TODT. The TODT identified using this novel NMR method is consistent with that determined using SAXS.

*Funding for this work was provided by the National Science Foundation through Award DMR-1505444. Small Angle X-Ray scattering work at the Advanced Light Advanced Light Source was supported by contract no. DE-AC02-05CH11231. Work at the Stanford Synchrotron Radiation Light Source at SLAC National Accelerator Laboratory was supported by contract no. DE-AC02-76SF00515. NMR work was supported by the UC Berkeley College of Chemistry NMR Facility.

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Presenters

  • Lorena Grundy

    • Chemical and Biomolecular Engineering, University of California, Berkeley

Authors

  • Lorena Grundy

    • Chemical and Biomolecular Engineering, University of California, Berkeley

  • Gurmukh Sethi

    • Materials Science and Engineering, University of California, Berkeley
    • University of California, Berkeley

  • Michael Galluzzo

    • Chemical and Biomolecular Engineering, University of California, Berkeley
    • University of California, Berkeley

  • Nitash Balsara

    • Chemical and Biomolecular Engineering, University of California, Berkeley
    • University of California, Berkeley
    • The Department of Chemical & Biomolecular Engineering, University of California Berkeley