Flexible Fe2 O3 and V2 O5 Nanofibers as Binder-Free Electrodes for High-Performance All-Solid-State Asymmetric Supercapacitors.

Flexible, highly porous Fe2 O3 and V2 O5 nanofibers (NFs) have been synthesized by a facile electrospinning method followed by calcination. They have been directly used as binder-free electrodes for high-performance supercapacitors. These Fe2 O3 and V2 O5 NFs interconnect with one another and construct three-dimensional hierarchical porous films with high specific surface areas. Benefitting from their unique structural features, binder-free Fe2 O3 and V2 O5 porous nanofiber electrodes offer high specific capacitances of 255 F g-1 and 256 F g-1 , respectively, at 2 mV s-1 in 1 m aqueous Na2 SO4 as electrolyte. An all-solid-state asymmetric supercapacitor (ASC) has been fabricated using Fe2 O3 and V2 O5 nanofibers as negative and positive electrodes, respectively. It could be operated at up to 1.8 V, taking advantage of the wide and opposite potential windows of the respective electrodes. The assembled all-solid-state ASC achieved a high energy density up to 32.2 W h kg-1 at an average power density of 128.7 W kg-1 , and exhibited excellent cycling stability and power capability. The effective and facile synthesis method and superior electrochemical performance described herein make electrospun Fe2 O3 and V2 O5 NFs promising electrode materials for high-performance ASCs.