Iron/vanadium co-doped tungsten oxide nanostructures anchored on graphitic carbon nitride sheets (FeV-WO3@g-C3N4) as a cost-effective novel electrode material for advanced supercapacitor applications

In this work, we studied the effect of iron (Fe) and vanadium (V) co-doping (Fe/V), and graphitic carbon nitride (g-C3N4) on the performance of tungsten oxide (WO3) based electrodes for supercapacitor applications. The lone pair of electrons on nitrogen can improve the surface polarity of the g-C3N4electrode material, which may results in multiple binding sites on the surface of electrode for interaction with electrolyte ions. As electrolyte ions interact with g-C3N4, they quickly become entangled with FeV-WO3nanostructures, and the contact between the electrolyte and the working electrode is strengthened. Herein, FeV-WO3@g-C3N4is fabricated by a wet chemical approach along with pure WO3and FeV-WO3. All of the prepared samples i.e., WO3, FeV-WO3, and FeV-WO3@g-C3N4 were characterized by XRD, FTIR, EDS, FESEM, XPS, Raman, and BET techniques. Electrochemical performance is evaluated by cyclic voltammetry (CV), galvanic charge/discharge (GCD), and electrochemica limpedance spectroscopy (EIS). It is concluded from electrochemical studies that FeV-WO3@g-C3N4exhibits the highest electrochemical performance with specific capacitance of 1033.68 F g-1at scan rate 5 mV s-1in the potential window range from-0.8 to 0.25 V, that is greater than that for WO3(422.76 F g-1) and FeV-WO3(669.76 F g(-1)). FeV-WO3@g-C3N4has the highest discharge time (867 s) that shows it has greater storage capacity, and its coulombic efficiency is 96.7%, which is greater than that for WO3(80.1%) and FeV-WO3(92.1%), respectively. Furthermore, excellent stability up to 2000cycles is observed in FeV-WO3@g-C3N4. It is revealed from EIS measurements that equivalent series resistance and charge transfer values calculated for FeV-WO3@g-C3N4are 1.82Uand 0.65U, respectively.

Automated summary

This work investigates the effects of iron and vanadium co-doping and graphitic carbon nitride on the performance of tungsten oxide electrodes for supercapacitor applications. The study demonstrates that the introduction of iron and vanadium co-doping and graphitic carbon nitride can significantly enhance the electrochemical performance of the electrodes, resulting in higher specific capacitance and longer discharge time. Furthermore, FeV-WO3@g-C3N4 exhibits excellent stability.