Inorganic-organic polymer electrolytes based on PEG400 and Al[OCH(CH3)2]3: I.: Synthesis and vibrational characterizations

Eleven new aluminum-based organically modified ceramics as polymer electrolytes were prepared and characterized. The hybrid inorganic-organic networks with the general formula {Al[O(CH2CH2O)(8.7)](rho)/(LiClO4)(z)}(n), where 1.85 less than or equal to rho less than or equal to 2.24 and 0 less than or equal to z less than or equal to 1.06, were prepared by a polycondensation reaction starting from aluminum isopropoxide and poly(ethylene glycol) (PEG400)/(LiClO4)(y) liquid polymer electrolytes with 0 less than or equal to y less than or equal to 0.49. Detailed compositional data, Fourier transform infrared (FTIR), and FT-Raman investigations allowed us to propose a structural hypothesis for this class of materials and to characterize the interactions between ions and binding sites in the host networks. These materials present a glassy rubbery consistency and consist of Al atoms bonded together by PEG400 bridges. Medium FTIR and FT-Raman studies of the polymers showed that the polyether moieties exhibit a TGT (T trans, G gauche) conformation with helical geometry and detected the presence of Li+...ClO4-...Al[O(CH2CH2O)(8.7)](3) neutral species at c(Li)(1/2) greater than or equal to 0.4 (mol kg(-1))(1/2). We verified that in bulk {Al[O(CH2CH2O)(8.7)](rho)/(LiClO4)(z)}(n) complexes the acid aluminum cross-linking sites exhibit the anion trapping phenomenon toward perchlorate anions. (C) 2004 The Electrochemical Society.