Facile synthesis of carbon-mediated porous nanocrystallite anatase TiO2 for improved sodium insertion capabilities as an anode for sodium-ion batteries

Porous carbon-mediated nanocrystallite anatase TiO2 composites are synthesized successfully via a simple dilatory hydrolysis-calcination method. The structural and morphological characterizations reveal that carbon-mediated TiO2 with a carbon content of 9.9 wt % (C2-TiO2) shows a combination of mesoporous and macroporous structures with a pore volume of 0.20 cm(3) g(-1) and surface area of 40.3 m(2) g(-1). Notably, C2-TiO2 delivered enhanced electrochemical performances of a high charge capacity of 259 mA h g(-1) at 0.1 C and a high rate performance of 110 mA h g(-1) after 150 cycles, even at 1 C. A significant decrease is also observed in the electrochemical impedance of the carbon-mediated samples, which explains superior electrochemical performance. Compared with the bare anatase TiO2 (B-TiO2), improved sodium storage capabilities of carbon-mediated samples are attributed to the participation of carbon to form a symbiotic structure with TiO2, which not only increases pore volume of the samples but serves as highly conductive network to provide a Na+ diffusion path during the insertion/de-insertion of sodium ions. All of these encouraging results suggest that carbon-mediated TiO2 has a great potential for improving sodium insertion capabilities with a facile and low-cost synthesis process. (C) 2017 Elsevier B.V. All rights reserved.