Architecting nickel vanadate-multiwall carbon nanotube nanocomposites-based electrodes for supercapacitor applications

This study introduces a simple and environmentally friendly hydrothermal method for creating sponge-like nickel vanadate (Ni₃V₂O₈, NVO) nanostructures that are attached to multiwalled carbon nanotubes (MWCNTs) to improve the performance of electrochemical energy storage. The novel in-situ anchoring of NVO on conductive MWCNT frameworks creates a three-dimensional interconnected network that allows ions and electrons to move quickly. XRD, FESEM, TEM, and XPS analyses of the structure and morphology showed that the NVO/MWCNT composites were phase-pure and evenly spread out, with strong interfacial coupling. Electrochemical tests showed that NVO/MWCNT-5 had a much higher specific capacitance of 389 F/g at 2 mA/cm², which is almost twice as high as that of pure NVO (201 F/g). The NVO/MWCNT-5//AC asymmetric supercapacitor had an energy density of 4.86 Wh/kg and kept 93 % of its capacity after 10,000 cycles. These results confirm the proposed hybrid design, which combines the high pseudocapacitance of NVO with the great conductivity and mechanical strength of MWCNTs. The material's ability to be made in large quantities, its low cost, and its compatibility with the environment make it a good choice for next-generation energy storage in portable electronics, hybrid electric vehicles, and grid-level systems.