Reaction-transport coupling driven by supramolecular host-guest chemistry accelerates kinetics in solid-state lithium-sulfur batteries

초록

In solid-state lithium-sulfur batteries (SSLSBs), sulfur redox kinetics are hindered by the misalignment between charge transport and catalytic sites, further aggravated by restricted poly(ethylene oxide) (PEO) chain mobility. Here, a supramolecular host-guest strategy is proposed to compress the effective reaction spatial scale of sulfur by constructing co-localized reaction domains within the solid-state electrolyte. Specifically, Indium oxide nanoparticles encapsulated by lithium sulfonated beta-cyclodextrin (S-CD), forming the composite denoted as In2O3@S-CD, are integrated into PEO matrix. Where the hydrophobic cavities and sulfonate groups of S-CD simultaneously confine polysulfides and Li+ as dual-guest species, while In2O3 provides active catalytic sites. This supramolecular confinement reconstructs the local reaction environment and enforces nanoscale co-location of reactants and charge carriers. Molecular dynamics simulations and radial distribution function analyses reveal a pronounced compression of the reaction space, which lowers the energy barrier for the newly rate-determining step (Li2S6 -> Li2S4) from 0.62 eV to 0.32 eV in the PEO system. Consequently, the assembled SSLSBs deliver 1108.30 mAh g(-1) at 0.10 C with >98% Coulombic efficiency, offering a quantifiable supramolecular paradigm for engineering nanoscale reaction interfaces in SSLSBs.

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