Polymer-Promoted Synthesis of Porous TiO2 Nanofibers Decorated with N-Doped Carbon by Mechanical Stirring for High-Performance Li-Ion Storage

Extensive efforts have been devoted to developing simple, low-cost, and high-production-yield methods to prepare hybrid materials with desired structural features for high-performance lithium storage. Here, a novel strategy is reported for fabricating the porous TiO2 nanofibers decorated with N-doped carbon (TiO2/C nanofibers) by a combination of mechanical stirring and the addition of a polymer in a beaker at ambient temperature, followed by calcination. The mechanical stirring process can provide homogeneous mixing of reactants in a solution, whereas the polymer acts not only as a structure-directing agent for fabricating one-dimensional nanofibers but also as the carbon and nitrogen source to generate N-doped carbon framework and porous structures. The TiO2/C nanofibers have average diameters of 500 nm and lengths up to 65 μm and are further composed of intercrossed TiO2 nanocrystals with sizes of 8 nm, with micropores centered at 1.5 nm and mesopores at 3–6 nm. The TiO2/C electrodes demonstrated a high reversible capacity (368 mAh g–1 at 0.25C after 200 cycles), good cycling performance (176 mAh g–1 at 10C over 2000 cycles), and excellent rate capability (97 mAh g–1 at 20C).