Two problems in disordered materials: I. Medium-range order structure of boron oxide glass. II. Structure and dynamics of organic-inorganic composite polymer electrolytes

Two disordered materials, B₂O₃ glass and solid polymer electrolyte, are investigated with solid state nuclear magnetic resonance (NMR) and Raman spectroscopy.; I. The number of boron atoms in boroxol ring structures was determined from the 2D anisotropy correlation NMR experiment. The anisotropy of boron atoms was correlated under the Off-Magic Angle Spinning condition. 66% of boron atoms were found to be in rings in B₂O₃ glass by comparing spin diffusion efficiency between neighboring boron atoms in glass and crystalline form. This figure is consistent with many experimental results.; II. For solid polymer electrolytes, mainly solid state NMR and Raman spectroscopy are used to study the structure and the dynamics. 27Al and 29Si NMR revealed the polyhedra present in organic-inorganic composite (OIC) and electrolytes. 1H spin diffusion NMR showed the presence of nanosized mobile PEO phases. Raman and DSC showed that the crystallinity of PEO has been suppressed by inclusion of OIC into the electrolyte. Reduced ionic interaction was confirmed by Raman spectroscopy. 19F multiple quantum spin counting NMR showed that triflate anions are more evenly distributed in the presence of OIC. Conductivity and the activation energy obtained from 7Li relaxation NMR were found to be optimized at 47% OIC electrolytes, strongly suggesting that the existence of OIC/electrolyte interface engendered new ion conduction pathways.