Hierarchical Ion-Conducting Materials Based on Polymer-Aligned Nanoparticles within Poly(vinyl benzyl methoxy poly(ethylene oxide) ether)- block -polystyrene Diblock Copolymer

Abstract Solid polymer electrolytes based on poly(ethylene oxide) (PEO) are promising alternatives to liquid electrolytes for safer lithium-ion batteries. Here, we report hierarchical solid polymer electrolytes obtained by selectively incorporating lithium sulfonamide-functionalized polymer nanoparticles (LiNPs) into a microphase-separated poly(vinyl benzyl methoxy poly(ethylene oxide) ether)-block-polystyrene block copolymer. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and small-angle X-ray scattering (SAXS) demonstrate that the phase-segregated lamellar morphology of the block copolymer is preserved upon nanoparticle incorporation. Notably, the LiNPs preferentially localize within the poly(ethylene glycol)-rich lamellae, generating hierarchical structures with ordering across multiple length scales arising from block copolymer self-assembly, selective nanoparticle organization, and poly(ethylene glycol) crystallization. Differential scanning calorimetry (DSC) reveals that the crystallinity of the poly(ethylene glycol) phase depends strongly on nanoparticle loading and plasticizer content. These hierarchical electrolytes exhibit high ionic conductivity, which is further enhanced by the addition of sulfolane as a plasticizer. These results elucidate the interplay between hierarchical morphology, phase crystallinity, and ion transport in block copolymer-based solid electrolytes, providing design guidelines for mechanically robust solid electrolytes with enhanced transport performance.