Characterization of SnO-M_xO_y (M=B and P) Glassy Anode Materials for Lithium Secondary Batteries Prepared by Melt-Quenching and Mechanical Milling

Abstract

Glasses in the systems SnO-B₂O₃ and SnO-P₂O₅ were prepared by melt-quenching and mechanical milling procedures. Glasses with higher SnO content, which could not be obtained by melt-quenching, were prepared by mechanical milling. Glass transition temperatures (T_g) in the SnO-P₂O₅ glasses were lower than those in the SnO-B₂O₃ glasses. The mechanically milled glasses showed lower T_g than the melt-quenched glasses. ³¹P MAS-NMR suggested that local structure around phosphorus atoms of the 67SnO•33P₂O₅ (mol%) glass obtained by mechanical milling was almost the same as the corresponding melt-quenched glass. The electrochemical properties of the SnO-based glasses were examined using a simple three electrodes cell with a conventional liquid electrolyte. The milled glasses as well as the quenched glasses worked as anode materials for lithium secondary batteries and exhibited high charge-discharge capacities.