A series of NASICON type compounds A1−xZr2−xNbx(PO4)3 (A = H, Li; x = 0, 0.02, 0.1, 0.2) were studied by 1H, 7Li, 31P nuclear magnetic resonance and impedance spectroscopy. The Nb substitution led to cation mobility enhancement and favored the triclinic–rhombohedral phase transition. The phase transition and a local Li motion were markedly increased by vacancy formation, while the cation conductivity was increased by interstitial formation in the LiZr2(PO4)3 structure.

Lithium and Hydrogen Ions Transport in Materials with NASICON Structure. I.A.Stenina, I.Y.Pinus, A.I.Rebrov, A.B.Yaroslavtsev: Solid State Ionics, 2004, 175[1-4], 445-9