A high-energy ball-milling process was used to prepare Ag-ion conductors from the compositions: AgI-20mol%Ag3PO4 and AgI-40mol%Ag3PO4. The former composition corresponded to that of the crystalline Ag7I4PO4 superionic phase, and the latter composition was reported to be a typical composition of superionic conducting glasses in this system. In AgI-20mol%Ag3PO4, ball-milling for more than 190h led to the formation of an unknown new crystalline phase. The new phase exhibited an ionic conductivity of 6 x 10−2S/cm at room temperature. The conductivity was higher than that of the crystalline Ag7I4PO4 phase. Ball-milling of 60AgI-40mol%Ag3PO4 made it amorphous, and the ball-milled samples exhibited a high ionic conductivity which was very similar to that of melt-quenched glass with the same chemical composition.

Mechanochemical Synthesis of a Silver Ion Conductor in the System AgI–Ag3PO4. N.Machida, S.Nishida, T.Shigematsu, H.Sakai, M.Tatsumisago, T.Minami: Solid State Ionics, 2000, 136-137, 381-6