Direct planting of ultrafine MoO2+δ nanoparticles in carbon nanofibers by electrospinning: self-supported mats as binder-free and long-life anodes for lithium-ion batteries.

Three-dimensional (3D) interconnected carbon nanofibrous mats containing well-dispersed MoO2+δ nanocrystals are fabricated through a facile electrospinning route followed by thermal treatment in N2. The resulting nanostructured monolithic hybrid mat made of C/MoO2+δ nanofibers exhibits superior Li-storage performances, when evaluated as a free-standing anode material. At a current density of 200 mA g(-1), a reversible capacity as high as 876.9 mA h g(-1) is achieved after 250 cycles. A capacity of 447.9 mA h g(-1) could still be maintained after 1000 cycles even at a high current density of 2000 mA g(-1), indicating high rate capability and cyclability. The attractive electrochemical performances of the as-obtained 3D C/MoO2+δ networks may benefit from the synergistic effects of the unique nanoarchitectures and the integrity of the electrodes. Monodispersed MoO2+δ nanocrystals encapsulated in carbon nanofibers not only provide interfacial storage but also improve the transport kinetics of electrons and lithium ions.