Hierarchical Fe2O3/Na2WO4 Nanofibers Supported on Conductive Carbon Cloth as a High-Performance Supercapacitor

Nanofibrous single metal oxides are promising electrode agents for electrochemical supercapacitors (ESCs). However, their cycling stability, capacitance, and rate efficiency still are required to be promoted for practical applications. To boost electrochemical supercapacitor (ESC) performance, it is critical to progressively develop a desirable morphology and high-surface-area electrode material as well as to design preferable electrode architecture. Therefore, we fabricated the α-Fe2O3/Na2WO4 nanofibers (NFs) by one-step coaxial syringe electrospinning of PVP-Fe­(NO3)3 and PVP/Na2WO4 followed by the calcination of the product. Polyvinylidene fluoride/N-methyl-2-pyrrolidone solution containing different amounts of as-prepared α-Fe2O3/Na2WO4 NFs with excellent processability and tolerability is prepared followed by casting on conductive carbon cloth (CC) as a distinguished electrode material, which satisfactorily reveals a specific capacitance up to 265.54 F g–1 between −0.8 and 0.8 V vs Ag/AgCl. The Cottrell and Dunn equations were applied to obtain 75.6% capacitive (non-faradaic) and 24.4% diffusion intercalation (faradaic) current. The coin-cell-based symmetric structured ESC assembled by two segments of CC-Fe2O3/Na2WO4 NF electrodes achieved 1.6 V operating voltage in 3.0 M Na2SO4 aqueous electrolyte and a specific capacitance of 160 F g–1 with superficial cycling stability, with 93% of initial capacitance retained after 200 cycles, revealing rapid ion-captive redox reactions on Fe2O3/Na2WO4 NF surfaces. The CC-Fe2O3/Na2WO4 NF symmetric ESC can carry an energy density of 50 Wh kg–1 at a power density of 514.28 W g–1. Our founding confirms that the CC-Fe2O3/Na2WO4 NF composite can act as a promising ideal electrode material for high-performance symmetric ESCs.