Abstract
Composite electrolytes composed of a polymer electrolyte and an ion-conducting ceramic are promising in fulfilling the requirements for a stable lithium metal anode. In this work, we identify the effects of the surface of a lithium-ion-conducting ceramic, the Ohara LICGC™ ceramic, on the segmental dynamics and ionic conductivity of polymer electrolyte consisting of poly(ethylene oxide) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Using quasi-elastic neutron scattering, we study the segmental motion of PEO chains under the confinement of LiTFSI salt and Ohara ceramic, in to the melt state (363 K). We compare the relaxation time, τ, and the monomeric friction coefficient, ζ, of four samples: neat PEO, PEO + Ohara ceramic, PEO + LiTFSI and PEO + LiTFSI + Ohara ceramic. In the absence of LiTFSI, Ohara ceramic posed negligible change in the segmental dynamics of PEO. In contrast, with the presence of LiTFSI, Ohara ceramic slowed down the segmental motion of PEO chains by ∼60% compared to neat PEO + LiTFSI. The intrinsic ionic conductivity of the polymer phase in the composite decreased by ∼30% compared to the neat polymer electrolyte. The underpinnings of these results may be that polymer chains in the vicinity of the ceramic surface are less mobile due to coordination with surface bound lithium ions.
| Original language | English |
|---|---|
| Pages (from-to) | 379-385 |
| Number of pages | 7 |
| Journal | Molecular Systems Design and Engineering |
| Volume | 4 |
| Issue number | 2 |
| DOIs | |
| State | Published - Apr 2019 |
Funding
This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and Engineering (XCC, RLS, NJD). Work at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for U.S. DOE under contract no. DEAC05-00OR22725. Access to the HFBS was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Differential scanning calorimetry experiments were conducted at the Center for Nanophase Materials Sciences (CNMS), a User Facility sponsored by DOE Office of Science. The identification of any commercial product or trade name does not imply endorsement or recommendation by the National Institute of Standards and Technology (NIST). This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Science and Engineering (XCC, RLS, NJD). Work at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC, for U.S. DOE under contract no. DEAC05-00OR22725. Access to the HFBS was provided by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-1508249. Differential scanning calorimetry experiments were conducted at the Center for Nanophase Materials Sciences (CNMS), a User Facility sponsored by DOE Office of Science.