Precise Synthesis of Acrylate-Terminated Poly(Triethylene Oxide Glycidyl Ether) via Anionic ROP for Enhanced Lithium-Ion Conductivity in Hybrid Solid Electrolytes

Solid polymer electrolytes (SPEs) are essential for ensuring high safety operations and enabling flexible device applications of lithium-ion batteries (LIBs). However, conventional SPEs suffer from insufficient lithium-ion conductivity, limiting their effectiveness in high-performance LIBs. In this study, we developed hybrid solid electrolytes (HSEs) that exhibit superior lithium-ion conductivity by integrating a precisely designed polymer matrix with inorganic silica nanoparticles. The polymer matrix, poly(triethylene oxide glycidyl ether) diacrylate (PTG), was synthesized via anionic ring-opening polymerization, which provided precise control over the molecular weight (MW) and chain architecture. This synthetic strategy enabled us to systematically investigate the relationship between polymer chain length, phase behavior, and lithium-ion transport within the hybrid electrolyte framework. The HSEs were fabricated using PTG, poly(ethylene glycol) diacrylate (PEGDA), and thiolated silica nanoparticles, where the PTG MW, PTG/PEGDA ratio, and lithium salt concentration were optimized to engineer efficient ion transport channels. The highest lithium-ion conductivity of 3.2 × 10–3 S/cm at 30 °C was achieved with an HSE formulated with 4.2 kDa PTG, a PTG/PEGDA ratio of 1.0, and a lithium salt concentration of 0.06 [Li]/[EO].