Thermal. electrical, and electrochemical properties were investigated for the (100-x)(0.6Li(2)S.0.4SiS(2)).xLi(4)SiO(4) oxysulfide glasses. The glass with x = 5 exhibited high electrical conductivity of about 10(-3) S cm(-1) at room temperature, high glass stability against crystallization, and good chemical stability in contact with ti metal. Cyclic voltammetry also suggested that this glass has a wide electrochemical window of more than 10 V. On the other hand, further addition of Li4SiO4 up to 20 mol % lowered the conductivity, glass stability against crystallization, and electrochemical stability for the oxysulfide glasses.