The monoclinic phase (P21/n) was formed for x = 0 to 0.6, and a NASICON-type rhombohedral phase (R¯3c) was obtained for x = 0.8 to 1.2 in the Li3-2xCr2-xTax(PO4)3 system. The activation energy for Li+ migration was about 0.45eV for the monoclinic structure and about 0.36eV for the rhombohedral structure. The maximum conductivity of 8.4 x 10-6S/cm at 298K was obtained for x = 0.8 of the Li3-2xCr2-xTax(PO4)3 system. The conductivity of LiCrTa(PO4)3 was enhanced by some 3 to 5 times by the addition of the Li salt; due to an improvement in sinterability. The maximum conductivity was 2.4 x 10-5S/cm at 298K for LiCrTa(PO4)3–0.2Li3BO3.

Ionic Conductivity and Crystal Structure for the Li3-2xCr2-xTax(PO4)3 System. H.Aono, M.Asri bin Idris, Y.Sadaoka: Solid State Ionics, 2004, 166[1-2], 53-9