The
development of advanced electrolytes compatible with lithium metal and
lithium-ion batteries is crucial for meeting ever growing energy storage
demands. One such class of materials, single-ion conducting polymer
electrolytes (SIPEs), prevents the formation of ion concentration gradients and
buildup of anions at the electrode surface, improving performance. One of the
ongoing challenges for SIPEs is the development of materials that are
conductive enough to compete with liquid electrolytes. Presented herein is a
class of gel SIPEs based on crosslinked poly(tetrahydrofuran) diacrylate that
present enhanced room temperature conductivities of 3.5 × 10<sup>-5</sup> S/cm
when gelled with lithium metal relevant 1,3-dioxolane/dimethoxyethane, 2.5 × 10<sup>-4</sup>
S/cm with carbonate solutions, and approaching 10<sup>-3</sup> S/cm with
dimethyl sulfoxide. Remarkably, these materials also demonstrate high
conductivity at low temperatures, 1.8 × 10<sup>-5</sup> S/cm at -20 °C in certain
solvents. Most
importantly however, when contrasted with identical SIPEs formulated with
poly(ethylene glycol) diacrylate, the mechanisms responsible for the enhanced
conductivity are elucidated: decreasing Li<sup>+</sup>-polymer interactions and
gel solvent-polymer interactions leads to an increase in Li<sup>+</sup>
mobility, improving the ionic conductivity. These findings are generalizable to
various SIPE chemistries, and can therefore be seen as an additional set of
design parameters for developing future high conductivity SIPEs.
Enhanced Li+ Conduction Within Single-Ion Conducting Crosslinked Gel via Reduced Cation-Polymer Interaction
