High-rate and long-term cycle stability of lithium-ion batteries enabled by boron-doping TiO2 nanofiber anodes

Abstract

Although the well-known anatase, one of the allotropic forms of natural TiO2, was recently proposed for lithium-ion battery electrodes, the material generally suffers from reduced cyclability and limited power, due to kinetic drawbacks and to its poor charge transport properties. Here, boron (B)-doping anatase TiO2 nanofibers were synthesized via a facile sol-gel method and the electrospinning method for use as anodes. The incorporation of B element not only promotes the crystallization of the building subunits of the microporous TiO2, but also improves the electrochemical performance at higher current rates and longer cycles. A capacity of 147mAhg−1 at a current density as high as 4Ag−1 and an excellent long-term cycling stability with a capacity retention of 167.6mAhg−1 at the current rate of 2Ag−1 over 5000cycles could be achieved when an appropriate amount of B was doped into TiO2 anodes. The reasons for the improvement of rate capability may be attributed to the enhancement of electronic conductivity, lithium ion diffusion kinetics, and the surface storage property for the B-doping anatase TiO2 anodes.