Structural and dynamic properties of LiNO$_3$ + Al$_2$O$_3$ nanocomposites

The structural and dynamic properties of lithium nitrate LiNO$_3$ and its heterogeneous composites with a nanopowder of aluminum oxide Al$_2$O$_3$ at different temperatures, phase states, and concentrations of the Al$_2$O$_3$ nanopowder have been investigated using Raman scattering, differential thermal analysis, and X-ray diffraction. It has been shown that, in the $(1-x)$LiNO$_3$ + $x$Al$_2$O$_3$ composites, an amorphous phase (for $x\ge$ 0.5) is formed, whose thermal effect is observed at 185$^\circ$C. The calculations of the dynamic characteristics of vibrations of the nitrate ion, as well as the differential thermal and X-ray diffraction analyses, have demonstrated that the nanocomposite can be represented as a highly disordered “quasilattice” in which “sites” are occupied by nanoparticles with amorphous lithium nitrate shells and spaces between them (conventionally “interstitial sites”) become channels of a facilitated flow of the ion current.