Neutron scattering studies of glassy Li$^{+}$ superionics

Two distinct neutron scattering techniques were implemented in the study of glassy superionic materials composed of a complex network of their interconnected sub-units: Li$_2$O, NH$_4$H$_2$PO$_2$, and Li$_2$SO$_4$. The use of disordered materials underlies an effort to promote Li$^{+}$ mobility, while suppressing e$^{-}$ conductivity, which makes them good candidates for use as electrolytes in lithium ion batteries. We present triple-axis spectrometer results of energy resolved vs. energy integrated neutron scattering that indicate the presence of a broad range of dynamic processes in the materials, rather than well-defined excitations. Additionally, we report on neutron diffraction data that demonstrates the formation of crystallites within the material upon annealing up to 450 $^{\circ}$C. Such crystallites hinder the performance of the materials as electrolytes, which is evident in thin film devices where heating is unavoidable during fabrication.