Crystal chemistry and electrical study of NaxNbTi(PO4)3

The NaxNbTi(PO4)3 solid solution with NASICON-type structure (R3c) occurs for 0⩽x⩽2. Ionic and electronic componen ts of the electrical conductivity have been studied versus composition and temperature. Reversible intercalation of sodium in NbTi(PO4)3 at room temperature can be achieved electrochemically. EMF and incremental capacity versus Na-composition provide evidence for a structural ordering of sodium in NaxNbTi(PO4)3 during intercalation.