Exploration of the role of oxygen-deficiencies coupled with Ni-doped V2O5 nanosheets anchored on carbon nanocoils for high-performance supercapacitor device

Electronic structural engineering via integration of oxygen deficiencies and a variety of dopants in metal oxide electrodes has fascinated the research interest for developing next-generation supercapacitors. Herein, by incorporating Ni dopants and creating O vacancies, it has thoroughly been explored the potential of vanadium oxide (V2O5) nanosheets anchored on the carbon nanocoils (CNCs) grown on nickel foam (NF) for supercapacitor electrodes (OV-Ni-V2O5/CNCs/NF). We validate a synergistic effect provided by heterostructure designed with multifunctional nano geometries. It is found that O vacancies and Ni dopants alter the electronic states of V2O5 with enhanced electrical conductivity and enriched redox active sites. We optimized O vacancies and achieved a specific capacity of 3485F g−1 (1742.5C g−1) at 1 A/g, representing ∼ 3.8 × higher compared to the best prior report. Furthermore, an asymmetric supercapacitor device was assembled with binder-free electrodes, using O0.075-V2O5/CNCs/NF as a cathode and sulfur-doped CNCs as an anode, which delivered a high energy density of 144 W h kg−1 and long-term stability of 5000 cycles, which is superior to most of the previous studies. This study paves a rational strategy to design high-performance electrodes for next-generation supercapacitors and other energy storage technologies.