EMIMTFSI-Induced plasticization and crystallinity suppression in PEO/ENR-25 polymer electrolytes: A DFT-assisted study of structural and electrochemical performance
Electrochimica Acta, cilt.567, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 567
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.electacta.2026.148839
- Dergi Adı: Electrochimica Acta
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC
- Anahtar Kelimeler: DFT calculation, ENR-25, Ion conduction, Ionic liquid, Plasticization, Poly (ethylene oxide) (PEO), Polymer electrolyte
- İnönü Üniversitesi Adresli: Evet
Özet
This work addressed plasticized polymer electrolytes consisting of a fixed blend of poly(ethylene oxide) and 25% epoxidized natural rubber (ENR-25), doped with lithium bis(trifluoromethanesulfonyl)imide and varying contents of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide have been prepared and investigated to understand the conduction mechanism as a function of ionic liquid (IL) content. The inclusion of IL achieved the maximum ionic conductivity ( σ ) of 1.59 × 10–5 S cm-1 at room temperature, the lithium-ion transference number ( t Li+) of 0.57, and the electrochemical stability window (ESW) up to 4.9 V vs. Li/Li+. These effects are correlated with a considerable reduction in the glass transition temperature ( T g), which reflects the plasticizing effect of the IL and the enhanced segmental mobility of the polymers. Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT) calculations at the ωB97X-D/def2-TZVP level revealed the preferential coordination of Li+ ions to the ether groups of the PEO rather than ENR-25 epoxide sites. Frontier molecular orbital (FMO) and conceptual DFT (CDFT) further showed a reduction in the HOMO-LUMO gap (Δ E ) and the chemical hardness ( η ), which are indicators of the enhanced electronic softness. Overall, the results clearly establish that IL-induced T g depression and changes in Li+ coordination chemistry have a direct influence on σ , Li+ mobility, and electrochemical stability.