Abstract:
Improving cycle life and rate capability through unique morphological features is beneficial for developing the energy storage capacity of supercapacitors (SC). The evolving use of abundant earth metals in low-cost metal tungstate (MWO4) with superior specific capacitance and excellent stability in nontoxic electrolytes continues to be a challenge. This work develops nanorods (NRs) architectured iron tungsten (FeWO4) electrode material for supercapacitors using a simple and industrially scalable method. The developed FeWO4 nanorods display an excellent specific capacitance of 465 F g–1 at a current density of 2 A g–1 with an admirable 98% capacitive retention over 3000 cycles. The electrode’s diffusive and capacitive impacts are investigated for a detailed understanding. Next, an FeWO4 NR-based symmetric supercapacitor was assembled in an aqueous electrolyte which displays areal capacitance of 116 mF cm–2 in a potential window of 1.2 V. Surprisingly, the assembled device shows a capacitance retention of ∼93% over 50 000 continuous cycles with no noticeable changes in electrochemical behavior. Besides giving valuable insights toward the electrochemical properties of FeWO4, this work demonstrates the potential of a device with exceptional stability in a nontoxic aqueous electrolyte that might compete with the most stable commercial carbon-based electrochemical capacitors.