Formation of bismuth metal in bismuth borate glass by reductive heat treatment and its electrochemical property as anode in lithium ion battery

Abstract

The crystallization behavior of bismuth borate glass in hydrogen argon mixed atmosphere was examined. When the 70B₂O₃–30Bi₂O₃ glass prepared by the melt quenching method was heat treated in a 5% hydrogen-95% argon atmosphere, spherical bismuth metal particles were formed in the glass matrix at 380°C, which is higher than glass transition temperature at 336°C and close to crystallization temperature at 399°C. As increase of heat treatment temperature, the diameter of bismuth grain was increased. Electrochemical activity of bismuth metal containing glass-ceramics was also evaluated as a negative electrode in lithium ion battery. Suppression of irreversible capacity at initial cycle due to lithium insertion was successfully performed by reductive heat treatment for crystallization of bismuth metal into glass matrix.