Self-doping Ti1-xNb2-xO7 anode material for lithium-ion battery and its electrochemical performance

Titanium niobium oxide (TiNb2O7) has been known as a potential candidate for the zero-strain material Li4Ti5O12 for power lithium ion battery, but its wide band gap energy (E-g similar to 2.0 eV), which representing low electronic conductivity, limits its application. Here, by adjusting the ratio of raw material TiO2 and Nb2O5, a series of Ti1-xNb2-xO7 (x = 0, 0.01, 0.02, 0.04, 0.06) were prepared via a high temperature solid-state reaction, and both the morphology and crystal structure of Ti1-xNb2-xO7 remained unchanged. The band gap calculated by the first-principle was 0.768 eV for Ti0.98Nb2.02O7, which proved that the electronic conductivity was improved, and the electrochemical performance was also enhanced. The reversible capacities Ti0.98Nb2.02O7 was higher than that of pure TiNb2O7 at different current density, and also its cycle performance was improved. All these results demonstrated that self-doping was an effective method to improve the electrochemical performance of TiNb2O7. (C) 2017 Elsevier B.V. All rights reserved.