Nitrogen-treated Hierarchical Macro-/Mesoporous TiO2 Used as Anode Materials for Lithium Ion Batteries with High Performance at Elevated Temperatures

In this article, we employed nitrogen gas treatment as an effective strategy in caclination to significantly improve the performance of hierarchical macro-/mesoprous TiO2 as anode materials for lithium ion batteries at an elevated temperature of 55 degrees C. Room-temperature synthesized macro-/mesoprous TiO2 was calcined under nitrogen and air conditions at 300 degrees C for 3 h, respectively. The specific surface area was studied by nitrogen adsorption/desorption measurement and the surface chemistry was studied by X-ray photoelectron spectroscopy (XPS). It was found that the macro-/mesoprous TiO2 had a specific surface area of 330 m(2) g(-1) after calcination under nitrogen atmosphere, while only 248 m(2) g(-1) after calcination under air atmosphere. Electrochemical tests showed that, in comparison to air-treated TiO2, nitrogen-treated TiO2 exhibited considerable high capacity and good rate performance as a lithium ion battery anode at the elevated temperature (55 degrees C). It had a capacity of 293 mAhg(-1) after 50 cycles at mixed current densities of 30, 150, and 500 mA g(-1), while the air-treated TiO2 only had a capacity of 187 mAhg(-1) after 50 cycles. This improvement of lithium ion storage capability can be ascribed to the nitrogen-treatment effect on crystallinity and the presence of surface defects on TiO2 nanostructure. (C) 2015 Elsevier Ltd. All rights reserved.