Synthesis and structure analysis of a new titanium oxide having an intergrowth structure between ramsdellite-type and calcium ferrite-type Original Research Article

A new crystal phase of LixTiO2 is synthesized by Sodium/Lithium ion exchange from high-pressure synthesized CaFe2O4-type NaxTiO2. The crystal structure is analyzed by single crystal X-ray diffraction data and refined to the conventional value of R=9.61% for 812 independent observed reflections. The crystal data of the LixTiO2 are as follows; the crystal system is orthorhombic, the space group is Pnam and the lattice parameters are a=17.513(25), b=10.651(7) and c=2.962(3) Å. The crystal has an intergrowth structure between ramsdellite-type and calcium ferrite (CaFe2O4)-type, alternatively. The electrochemical property shows the initial Li intercalation capacity is 219 mA h g−1 and the corresponding energy density is 384 W h kg−1. The capacity is maintained after 20 cycles of charge–discharge reaction.