Structural and electrical characterization of glasses in the system Li2Se-SiSe2 by 29Si MAS NMR and Raman spectroscopy
Abstract The structure of glasses in the system (Li 2 Se) x (SiSe 2 ) 1− x (0≤x≤0.70) has been characterized by combined Raman and 29 Si magic-angle spinning (MAS) NMR measurements. In conjunction with parallel MAS NMR studies on crystallized specimens, the detailed silicon speciation has been derived as a function of composition. As in the compositionally analogous sulfide system, the spectra reveal the presence of both corner- and edge-sharing silicon tetrahedra, however, the overall fraction of edge-sharing species is lower in the selenide system. The electrical conductivity characteristics of both systems are in close analogy to each other.