Description:
<jats:p>Solvent-free block copolymers electrolytes are the strongest candidates for solid-state lithium metal batteries, as new polymers based on polyethylene oxide (PEO) and lithium bis(trifluoromethane)sulfonimide (LiTFSI) prevent the formation of lithium dendrites and ensure sufficient conductivity. </jats:p>
<jats:p>Block copolymers based on PEO and either polystyrene (PS) or grafted PS-TFSI were compared to PEO by Nuclear Magnetic Resonance spectroscopy (NMR) in order to quantify and distinguish the transport and dynamics of Li<jats:sup>+</jats:sup> and TFSI<jats:sup>-</jats:sup> and the effect of the polymer matrix. </jats:p>
<jats:p>The self-diffusion coefficients of Li<jats:sup>+</jats:sup> and TFSI<jats:sup>-</jats:sup> can be measured at various temperatures with pulsed-field-gradient (PFG) experiments and compared with electrical conductivity measurements, providing insights on lithium transport properties in each system. </jats:p>
<jats:p>We measured <jats:sup>7</jats:sup>Li NMR relaxation rates at various magnetic fields and temperatures, and we were able to extract complex correlation functions describing the fluctuations of the <jats:sup>7</jats:sup>Li quadrupolar interaction inside the polymer matrix, yielding insights into cation dynamics with three different timescales. These results obtained from NMR can be compared to molecular dynamics or theoretical calculations.</jats:p>