The Effects of LiTDI Salt and POSS-PEG (n=4) Hybrid Nanoparticles on Crystallinity and Ionic Conductivity of PEO Based Solid Polymer Electrolytes

Solid polymer electrolytes with good ionic conductivity at room temperature and mechanical flexibility are very attractive candidate for lithium-ion batteries. In this paper, we reported the effect of lithium 4,5-dicyano-2-(trifluoromethyl) imidazole (LiTDI) salt and inorganic-organic hybrid nano particles (POSS-PEG (n = 4)) on crystallinity and ionic conductivity of solid polymer electrolytes. The crystallinity of the solid polymer electrolytes have been characterized by X-ray diffraction (XRD) and Differential scanning calorimetry (DSC). The interactions between the ether oxygen and Li+ ions was studied by Fourier transformed infrared (FT-IR) spectroscopy. The Young's modulus increased from 0.462 to 0.56 MPa with the addition of POSS-PEG. The ionic conductivity of the films was investigated by impedance analysis. A solid polymer electrolyte with molar ratio EO:Li = 12 exhibits a maximum ionic conductivity of 2.05x10(-6) S/cm, which increases to 2.23 x 10(-5) S/cm by the addition of POSS-PEG nanoparticles (40 wt%) at room temperature 23 degrees C. The temperature dependent conductivity obeys Arrhenius behavior and the activation energy decreased to 0.295 eV. The electrochemical stability of the optimum conducting composition is 4.6 V, which make it attractive as electrolyte for Li battery.