Efficient ion intercalation for enhanced energy storage: A comparative study of VO₂(D)/g-C₃N₄ and VO₂(D)/PPY/g-C₃N₄ electrodes

This research provides a comparative assessment of our previously published findings to ascertain the ideal composition of VO₂(D), polypyrrole (PPY), and graphitic carbon nitride (g-C₃N₄) composites for super-capacitor applications. In this investigation, comprehensive calculations were conducted to quantify electrochemical performance metrics, identify the top-performing composite, and clarify the reasons behind its superior performance. Binary (VO₂/g-C₃N₄) and ternary (PPY/g-C₃N₄/VO₂(D)) nano-composites were synthesized through hydrothermal and in situ polymerization methods and characterized using X-ray diffraction, TGA, field emission scanning electron microscopy, transmission electron microscopy-energy-dispersive X-ray spectroscopy, and electrochemical techniques. Electrochemical performance, evaluated through cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy, demonstrated significant synergistic effects among the components. The composite designated as 3VO₂/g-C₃N₄ displayed a remarkable specific capacitance of 1416 F/g at 2 mV/s, accompanied by excellent cycling stability (106.1%), supported by low solution resistance (2.8 Ω) and charge transfer resistance (0.75 Ω). To further improve electrochemical performance, a ternary composite (PGV0.3) was created through in situ oxidative polymerization of pyrrole. PGV0.3 exhibited an impressive specific capacitance of 3263 F/g with outstanding stability (99.71% after 2000 cycles), along with a high energy density of 138.2 Wh/kg and power density of 218.69 W/kg. Based on these findings, PGV0.3 has been identified as the most effective configuration, achieving a balance between conductivity, electroactive surface area, and structural stability. This comparative analysis highlights the significance of optimizing composition and leveraging multi-component synergy in the development of advanced energy storage materials.