RESUMO
ABSTRACT: Hybrid materials of vanadium nitride and porous carbon nanoparticles (VN/PCNPs) were fabricated by a facile pyrolysis process of vanadium pentoxide (V2O5) xerogel and melamine at relatively low temperature of 800 °C for supercapacitor application. The effects of the feed ratio of V2O5 to melamine (r), and nitrogen flow rate on the microstructure and electrochemical performance were also investigated. It was found that the size of the as-synthesized nanoparticles is about 20 nm. Both r value and N2 flow rate have enormous impacts on morphology and microstructure of the nanoparticle, which correspondingly determined the electrochemical performance of the material. The VN/C hybrid nanoparticles exhibited high capacitive properties, and a maximum specific capacitance of 255.0 F g-1 was achieved at a current density of 1.0 A g-1 in 2 M KOH aqueous electrolyte and the potential range from 0 to -1.15 V. In addition, symmetrical supercapacitor fabricated with the as-synthesized VN/PCNPs presents a high specific capacitance of 43.5 F g-1 at 0.5 A g-1 based on the entire cell, and an energy density of 8.0 Wh kg-1 when the power density was 575 W kg-1. Even when the power density increased to 2831.5 W kg-1, the energy density still remained 6.1 Wh kg-1.
