Polycrystalline samples of the hexagonal phase were prepared by sintering at temperatures of between 400 and 698C, and the room-temperature conductivities were then measured at temperatures of between 99 and 650C. It was found that plots of conductivity versus temperature exhibited 2 different slopes; thus implying that Li+ ions had activation energies of differing magnitudes in various temperature ranges.

A.H.Yahaya, Z.A.Ibrahim, A.K.Arof: Journal of Alloys and Compounds, 1996, 241[1-2], 148-52