Structural transformation of layered hydrogen trititanate (H2Ti3O7) to TiO2(B) and its electrochemical profile for lithium-ion intercalation

The thermally-induced structural transformation of layered hydrogen trititanate (H2Ti3O7) to TiO2(B) has been systematically studied by means of in situ X-ray diffraction (XRD) over a wide temperature range from 170 to 450 °C. Our data indicate a structural transition realized via continuous loss of interlayer water, which results in a series of non-stoichiometric hydrogen titanate compounds (3TiO2·δH2O). Electrochemical analysis of hydrogen titanates for lithium-ion intercalation shows that reversible specific capacity increases as calcination temperature increases, whereas cycling stability decreases during the continuous dehydration process.