Li+ ion conducting γ solid solutions in the systems Li4XO4-Li3YO4: X=Si, Ge, Ti; Y=P, As, V; Li4XO4-LiZO2: Z=Al, Ga, Cr and Li4GeO4-Li2CaGeO4

A wide variety of solid solutions with a structure related to that of γ Li3PO4 may be prepared. These include materials such as lisicon, Li2+2xZn1-xGeO4 and the title systems, many of which have not been studied previously. Conductivity data are presented for eight systems: Li4GeO4-Li3(P, As, V)O4; Li4TiO4-Li3(As, V)O4; Li4GeO4-Li(Ga, Al)O2; Li4GeO4-Li2CaGeO4 and the results compared with those reported in the literature for Li4SiO4-Li3(P, As, V)O4 systems and lisicon. dc polarisation measurements were made on four of the system and it was found that the electronic transference number is 10−4 or less. The materials with the highest conductivity were found in the systems, Li4 (Ge, Ti) O4-Li3 (As, V)O4 with σ ~ (3 to 4) × 10−5 Ω−1 cm−1 at room temperature. It is noted that the systems with the highest conductivity are generally those with the largest unit cell volume.