Facile fabrication of interconnected-mesoporous T-Nb2O5 nanofibers as anodes for lithium-ion batteries

Abstract

Niobium pentoxide (Nb2O5) has been extensively studied as anode materials for lithium ion batteries (LIBs) due to its good rate performance and safety advantages. However, the intrinsic low electronic conductivity has largely restricted its practical application. In this work, we report the construction of mesoporous T-Nb2O5 nanofibers by electrospinning followed by heat treatment in air. The interconnected mesoporous structure ensures a high surface area with easy electrolyte penetration. When used as anodes for LIBs, the mesoporous Nb2O5 electrode delivers a high reversible specific capacity of 238 mA h g−1 after 1,000 cycles at a current density of 1 A g−1 within a voltage range of 0.01–3.0 V. Even at a higher discharge cut-off voltage window of 1.0–3.0 V, it still possesses a high reversible capacity of 166 mA h g−1 after 200 cycles. Moreover, the porous Nb2O5 electrode also exhibits excellent rate capability. The enhanced electrochemical performances are attributed to the synergistic effects of porous nanofiber structure and unique crystal structure of T-Nb2O5, which has endowed this material a large electrode-electrolyte contact area with improved electronic conductivity.