The electrochemical of cation-deficient TiO2 anatase could enhance significantly with the defect structure.1,2 The soft-chemistry synthetic routes of anatase phases usually require amorphous precursors derived from expensive and air-sensitive alkoxides.3 Here cation-deficient Nb-doped TiO2(NTO,formulated as Ti0.8Nb0.16□0.04O2)anatase has been successfully synthesized from layered K3Ti5NbO14 by one-pot hydrothermal route.The Rietveld refinement Neutron powder diffraction(NPD)data suggested that there was 3.8(5)%cationic vacancy in the Nb-doped TiO2 anatase crystal structure.When used as an anode of lithium ion batteries(LIBs),the NTO electrode displayed initial discharge and charge capacities of 618 and 384.6 mAh/g at a current density of 0.2 C respectively,with a remarkable discharge capacity maintained at~246.8 mAh/g after 100 cycles,representing the highest record among the reported Nb-doped TiO2 anatases under low current.A full cell,fabricated using the NTO electrode as anode and commercial LiCoO2 cathode,is shown to deliver discharge capacity of 230.2 mAh/g after 15 cycles,which exceeds those for the most previous reported full cells based on the TiO2 anode and makes this NTO material a promising anode candidate for LIBs.These results present a practical synthetic strategy of tuning cationic vacancies through aliovalent cationic substitution to improve the electrochemical performance of actual LIBs and possibly to develop further relevant devices.