Electrospun NbO nanorods/microporous multichannel carbon nanofiber film anode for Na ion capacitors with good performance.

For the disadvantages of both the slow reaction kinetics and the poor conductivity for NbO electrode materials as sodium-ion capacitors (SICs), NbO NRs/NMMCNF film electrode with good flexibility and high electrochemical property has been fabricated by electrospinning PAN/PMMA/HNbO·HO homogeneous viscous suspension and followed by an annealing treatment, in which the precursor HNbO·HO nanorods are obtained by grinding HNbO·HO nanowires, and NbO nanorods are uniformly embedded in nitrogen doped microporous multichannel carbon nanofiber. Benefiting from the multichannel network structure, NbO NRs/NMMCNF film electrode delivers the fast kinetics of Na-storage and the superior Na-ion storage performance, it delivers outstanding rate capability (101 mAh g at 4 A g) and ultralong lifespan (91% capacity retention after 10,000 cycles at 2 A g). A NbO NRs/NMMCNF//AC SIC based on the NbO NRs@NMMCNF fiber film anode and the AC cathode is assembled. The energy density of the as-assembled device is as high as 91 Wh kg and its maximum power density is 7499 W kg. This work offers a new structure design strategy toward intercalation-type metal oxide electrodes for application in SICs.