Detection of the Order-to-Disorder Transition in Block Copolymer Electrolytes Using Quadrupolar 7Li 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.

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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