Electrospun V _2O _5 nanostructures with controllable morphology as high-performance cathode materials for lithium-ion batteries

摘要

Porous V _2O _5 nanotubes, hierarchical V _2O _5 nanofibers, and single-crystalline V _2O _5 nanobelts were controllably synthesized by using a simple electrospinning technique and subsequent annealing. The mechanism for the formation of these controllable structures was investigated. When tested as the cathode materials in lithium-ion batteries (LIBs), the as-formed V _2O _5 nanostructures exhibited a highly reversible capacity, excellent cycling performance, and good rate capacity. In particular, the porous V _2O _5 nanotubes provided short distances for Li ~+-ion diffusion and large electrode-electrolyte contact areas for high Li ~+-ion flux across the interface; Moreover, these nanotubes delivered a high power density of 40.2 kW kg ~(-1) whilst the energy density remained as high as 201 W h kg ~(-1), which, as one of the highest values measured on V _2O _5-based cathode materials, could bridge the performance gap between batteries and supercapacitors. Moreover, to the best of our knowledge, this is the first preparation of single-crystalline V _2O _5 nanobelts by using electrospinning techniques. Interestingly, the beneficial crystal orientation provided improved cycling stability for lithium intercalation. These results demonstrate that further improvement or optimization of electrochemical performance in transition-metal-oxide-based electrode materials could be realized by the design of 1D nanostructures with unique morphologies.