Nanocomposite solid polymer electrolytes based on poly(ethylene oxide)/POSS-PEG (n = 13.3) hybrid nanoparticles for lithium ion batteries

• Novel POSS-PEG/PEO blended electrolytes were synthesized for Li-ion batteries.
• Reduction of crystallinity by adding salt and POSS-PEG was confirmed by XRD and DSC.
• Interaction of Li+ cation with ether oxygen of PEO and POSS-PEG was monitored by FTIR.
• POSS-PEG gave significant enhancement in conductivity and mechanical strength of SPEs.
• The compatibility between POSS-PEG and high molecular weight PEO was excellent.

We successfully prepared the nanocomposite solid polymer electrolytes based on poly(ethylene oxide) (PEO)/polyhedral oligomeric silsesquioxane-polyethylene glycol (POSS-PEG) complexed with LiN(SO2CF3)2 (LiTFSI) salt and studied the effect of POSS-PEG (n = 13.3) hybrid nanoparticles on structural, thermal, mechanical and ionic conductivity properties. The crystallinity of the nanocomposite solid polymer electrolytes has been characterized by X-ray diffraction (XRD). FTIR studies showed the evidence of the complexation between PEO, LiTFSI and POSS-PEG. Differential scanning calorimetry (DSC) was used to study their glass transition and melting behaviors and to measure their respective degrees of crystallinity. The degree of crystallinity reduced with POSS-PEG content, indicating restricted segmental motion of the polymer chains. The Young's modulus increased from 0.076 to 0.19 MPa with the addition of POSS-PEG. Ionic conductivity studies reveal that solid polymer electrolyte with 30 wt% of POSS-PEG has the highest ionic conductivity of 5.05 × 10−5 S/cm at room temperature (23 °C). The temperature dependence conductivity studies showed that the samples seemed to obey the Arrhenius behavior.

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