Performance analysis of three distinct NiV₂O single-phase nano self-assemblies for asymmetric supercapacitor...

Single-phase inorganic nanostructures with multiple applications are required for cost-effective, sustainable applications to save the environment from toxic activities. Nickel vanadate (NiV₂O), possessing three phases, such as NiV₂O₆, Ni₂V₂O₇, and Ni₃V₂O₈, acts as an effective electrode material and potential electrochemical sensors. Nickel vanadate phases (NiV₂O₆, Ni₂V₂O₇, and Ni₃V₂O₈) were synthesized through the gel-matrix technique, and their phase purity, crystallinity, morphology, optical properties, etc., were evaluated and studied. Electrochemical studies infer that NiV₂O₆ exhibits the highest specific capacity of 251 C g^-1 (69.7 mA h g^-1) at 1 A g^-1 compared to the other nickel vanadate phases and provides better cyclic stability of 80.19% for 5000 cycles. The asymmetric supercapacitor device fabricated from NiV₂O₆ results in a specific capacity of 189 C g^-1 (52.5 mA h g^-1), energy density of 59.06 W h kg^-1, and a power density of 1125 W kg^-1 with a capacitive retention rate of 74.91% and coulombic efficiency of 99.61% for 10 000 cycles. The electrochemical detection potential of NiV₂O in bifenox herbicide has been studied with all the synthesized nanostructures. Among them, NiV₂O₆-based sensor probes demonstrated excellent characteristics, including high sensing current and low detection limits of 0.6 nM with a linear range of 1-57 nM. The real-time herbicide detection of NiV₂O₆ in live samples was checked with freshly harvested potatoes. This advancement further enhances the utilization of NiV₂O materials for electrochemical applications.