High lithium ion conducting 70Li(2)S center dot(30-x)P2S5 center dot xP(2)S(3) (mol%) glasses and glass-ceramics were prepared by the mechanical milling method. Glasses were obtained in the composition range of 0 <= x <= 10. The substitution of P2S3 for P2S5 promoted the formation of the P2S64- units in the glasses. The conductivity of the glass increased with an increase in P2S3 contents up to 5 mol% and the glass with 5 mol% of P2S3 showed the conductivity of 1 x 10(-4) S cm(-1) at room temperature. In the case of glass-ceramics, the conductivity increased with an increase in P2S3 contents up to 1 mol%, and the superionic conducting Li7P3S11 crystal was precipitated in the glass-ceramic. The glass-ceramic with 1 mol% of P2S3 showed the highest conductivity of 3.9 x 10(-3) S cm(-1) at room temperature. (C) 2008 Elsevier B.V. All rights reserved.