Unique thermal conductivity, Young’s modulus and local structure of 72SnO–28P₂O₅ glass

Abstract

Tin-phosphate (SnO–P₂O₅) glasses with high SnO contents have a high potential for new lead-free low-melting sealing frits, optical materials, and anode active materials for rechargeable lithium ion batteries (LIBs). The local structure (Raman scattering and ¹¹⁹Sn Mössbauer spectra), some physical properties (specific heat and thermal conductivity), and elastic properties (Young’s modulus and Vickers hardness) of 72SnO.28P₂O₅ glass were characterized to clarify the features of SnO–P₂O₅ glasses. The glass showed unique properties when compared with other phosphate glasses, i.e., small thermal diffusivity and conductivity, small Young’s modulus, intense Boson peak, and unique local structure. 72SnO.28P₂O₅ glass has an open structure with a low packing density, in which a large number of Q¹ ((PO_3.5²⁻) and Q⁰ (PO₄³⁻) units are formed. These structural features would be one of the main reasons for the fast diffusion of Li⁺ ions and result in the excellent LIB performance as anode materials of the glass.