A3Ti5NbO14 (A = H, Li and K) family: ionic exchange, physical and electrochemical properties.

A new layered titanoniobate, Li3Ti5NbO14, a member of the AxM2nO4n+2 family, has been synthesized using a molten salt reaction between H3Ti5NbO14 and an eutectic mixture of LiOH and LiNO3. This compound crystallizes in the P21/m space group with a = 9.273(15) Å, b = 3.788(6) Å, c = 8.871(3) Å, and β = 114.33(1)°, as determined by 3D electron diffraction single crystal analysis. It exhibits [Ti5NbO14]3− layers similar to K3Ti5NbO14, but differs from the latter by a 'parallel configuration' of its [Ti5NbO5]3− ribbons between the two successive layers. The topotactic character of the reaction suggests that exfoliation plays a prominent role in the synthesis of this new form. This new phase intercalates reversibly 2 lithium through a first-order transformation leading to a capacity of 100 mA h g−1 at a potential of 1.67 V vs. Li/Li+. [ABSTRACT FROM AUTHOR]