Dual Surfactant-Assisted Hydrothermal Engineering of Co3V2O8 Nanostructures for High-Performance Asymmetric Supercapacitors

Abstract

This study presents a dual surfactant-assisted hydrothermal approach for the synthesis of Co3V2O8 (CoVO) nanostructures and their surfactant-modified derivatives, PVP-assisted Co3V2O8 (P-CoVO) and PVP-SDS co-assisted Co3V2O8 (P/S-CoVO), which were directly grown on nickel foam. The use of PVP and SDS enabled controlled nucleation and growth, yielding a hierarchical nanoflower-like morphology in P/S-CoVO with increased porosity, a higher surface area, and uniform structural features. Comprehensive physicochemical characterization confirmed that surfactant incorporation effectively modulated particle size, dispersion, and active-site availability. Electrochemical measurements demonstrated that P/S-CoVO exhibited superior performance, with the largest CV area, low equivalent series resistance (0.52 Omega), and a maximum areal capacitance of 13.71 F cm-2 at 8 mA cm-2, attributable to rapid redox kinetics and efficient ion transport. The electrode also showed excellent cycling stability, retaining approximately 83.7% of its initial capacitance after 12,000 charge-discharge cycles, indicating robust structural integrity and interfacial stability. Additionally, an asymmetric supercapacitor device (P/S-CoVO//AC) delivered a high energy density of 0.082 mWh cm-2, a power density of 1.25 mW cm-2, and stable operation within a 1.5 V potential window. These results demonstrate that cooperative surfactant engineering provides an effective and scalable strategy to enhance the morphology, electrochemical kinetics, and durability of Co3V2O8-based electrodes for next-generation high-performance supercapacitors.