Interface-Engineered Nickel Preinserted Vanadium Oxide (Ni_0.22V₂O₅) Nanobelts via Ultrasonic-Assisted Synthesis for High-Performance Solid-State Supercapacitors

Engineering nanostructured hybrid metal oxides via controlled ion preinsertion offers a promising strategy for enhancing interface properties, ion diffusion pathways, and structural integrity in energy storage materials. In this study, we report the synthesis of interface-engineered nickel-ion preinserted vanadium oxide (Ni 0.22 V 2 O 5 ) nanobelts using a facile and cost-effective ultrasonic-assisted chemical route. This approach facilitates nickel incorporation within the V 2 O 5 matrix, resulting in expanded interlayer spacing and a layered monoclinic structure that promotes synergistic redox activity from both V and Ni elements. The nanobelt morphology further enhances electroactive surface area and ion diffusion pathways. The prepared nanobelts demonstrate exceptional electrochemical performance, achieving a specific capacitance of 913 F g –1 at 0.5 A g –1, along with impressive cycling durability, retaining 90% capacitance after 10,000 cycles. Additionally, the fabricated asymmetric supercapacitor device delivers a optimal energy density of 45 Wh kg –1 and power density of 4876 W kg –1, as validated through light-emitting diode (LED) lighting demonstrations. This work introduces a scalable synthesis platform for next-generation supercapacitors through transition metal ion preinsertion and interface modulation.