Electrospun TiO2/C Nanofibers As a High-Capacity and Cycle-Stable Anode for Sodium-Ion Batteries.

Nanosized TiO2 is now actively developed as a low-cost and potentially high capacity anode material of Na-ion batteries, but its poor capacity utilization and insufficient cyclability remains an obstacle for battery applications. To overcome these drawbacks, we synthesized electrospun TiO2/C nanofibers, where anatase TiO2 nanocrystals with a diameter of ∼12 nm were densely embedded in the conductive carbon fibers, thus preventing them from aggregating and attacking by electrolyte. Due to its abundant active surfaces of well-dispersed TiO2 nanocrytals and high electronic conductivity of the carbon matrix, the TiO2/C anode shows a high redox capacity of ∼302.4 mA h g(-1) and a high-rate capability of 164.9 mAh g(-1) at a very high current of 2000 mA g(-1). More significantly, this TiO2/C anode can be cycled with nearly 100% capacity retention over 1000 cycles, showing a sufficiently long cycle life for battery applications. The nanofibrous architecture of the TiO2/C composite and its superior electrochemical performance may provide new insights for development of better host materials for practical Na-ion batteries.