Synthesis of NASICON-type lithium zirconium phosphate

The chemical transformations involved in the synthesis of the NASICON-type compound LiZr2(PO4)(3) were studied by thermogravimetry and x-ray diffraction. The results demonstrate that, during heat treatment of a 3Zr(HPO4)(2) 2H(2)O + Li2CO3 + ZrO2 mixture, the formation of the NASICON phase begins at 600degreesC. Further heating, however, leads to the concurrent formation of zirconium diphosphate and uncontrolled lithium losses because of the high volatility of Li compounds. A well-crystallized, high-conductivity NASICON phase is formed only above 1100degreesC. Phase-pure LiZr2(PO4)(3) can only obtained by a two-step procedure.