Lithium/sulfur batteries are a promising candidate for the post-lithium-ion era thanks to their high energy density and environmental friendliness. However, complex degradation mechanisms and a poor understanding of the polysulfide (PS) molecular structure and ether-based components have hindered their broad commercialization. In this study, Matej Kanduč and coworkers combined neutron scattering experiments with molecular dynamics simulations to elucidate this complex electrolyte and PS structure. A delicate balance between ion-ion and ion-solvent interactions was found, which steers the ordering and undesired clustering of Li⁺ and PS ions at moderate concentrations (> 1 M). In particular, ‘solvent-separated’ Li⁺ ions and PS/anions induce a cation and anion short-ranged alternating structure. At these conditions, the transport of Li⁺ ions becomes coupled between caged and jumping states within the 3D ionic network.

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Park et al., Energy Storage Mater. 52, 85-93 (2022)