Elucidation of TeO3 to TeO4 transition in bismuth tellurite glass for superionic glass host development

Our study pioneers the elucidation of the TeO3 to TeO4 transition in bismuth tellurite glasses, a pivotal advancement for solid-state battery through the optimization of tellurite-based superionic material hosts. FTIR spectroscopy revealed notable shifts in the TeO2 functional units' peaks, particularly the TeO3 peak moving to a lower wavenumber near the TeO4 peak at critical Bi2O3 concentrations of 7 & 11 mol%. This shift signifies a reduction in non-bridging oxygen sites (NBO), crucial for enhancing Li+ ion mobility. This finding was further substantiated by molecular dynamics simulations which identified Te-O pair distribution function g(r) peak at 1.817 Å, (the "3" short bonds) in pure TeO2 glass (0 mol% Bi2O3) and peak at 2.125 Å (the longer “+1” bond) at 10 - 50 mol% of Bi2O3, suggesting a structural shift towards TeO4 configurations. The intensity of this “+1” peak intensifies with Bi2O3 addition, marking a clear structural transition. Hence, our research proposes to leverage high-resolution neutron diffraction to dissect the Te atom environment and its coordination shift amidst increasing Bi2O3. The neutron diffraction study focuses on confirming the Te-O g(r), average Te-O coordination number nTeO, and average Te–O bond distance rTeO spanning xBi2O3-(100-x)TeO2 formulations (x = 0, 10, 20, 30, 40, to 50 mol%). We request 3 days on the General Materials Diffractometer (GEM) to facilitates total scattering measurements for this array of compositions.