Effect of nanoscopic confinement on improvement in ion conduction and stability properties of an intercalated polymer nanocomposite electrolyte for energy storage applications

Nanoscopic confinement of a cation coordinated polymer ill the channels of organo-modified montmorillonite clay results ill substantial improvement ill conductivity, cation transport and stability properties required for energy storage/conversion devices. X-ray diffraction analysis confirms composite formation as evidenced by: (i) intercalation of PEO8-LiClO4 into the clay channels for clay loading >= 7.5 wt.% and (ii) partial intercalation/exfoliation for a lower clay loading (<= 5 wt.%). Transmission electron microscopy analysis corroborates these findings as indicated by all enhancement in clay gallery width front 6 to 9 angstrom for 20wt.% clay providing evidence for intercalation at higher clay loadings. Energy dispersive X-ray dot-mapping images confirm the homogeneous distribution of clay in nanocomposites. Thermal analysis indicates a strong dependence of thermodynamic parameters, e.g., glass transition (T-g), crystalline melting (T-m) melting enthalpy, glass transition width (Delta T-g), and thermal relaxation strength (Delta C-p), oil clay concentration. These observations agree well with changes in electrical properties oil nanocomposite formation. Substantial enhancement in ambient conductivity (similar to 208 times) occurs in a nanocomposite film (2 wt.% clay) relative to a clay-free film. The temperature dependence of conductivity obeys Arrhenius behaviour below T-m and the VTF (Vogel-Tamman-Fulcher) relationship above T-m. The ionic transport number (similar to 99.9%) confirms ionic charge transport with a cation Contribution (t(Li+)) similar to 0.5 for 2 wt.% clay. represents a it increase by similar to 65% in comparison with PEO8-LiClO4. Improvement in voltage and thermal stability is also Observed with the nanocomposites. (C) 2009 Elsevier B.V. All rights reserved.