摘要
Background: Nanostructured mixed-valence vanadium oxides (VO x ) are attractive as electrode materials for supercapacitor applications. Development of suitable synthetic and characterization methods for the fabrication of VO x nanostructures with controlled properties is of crucial importance. Methods: A continuous aerosol-based synthetic route with in-situ mobility size characterization is developed to fabricate VO x nanoparticles (NPs) in this study. Differential mobility analysis, X-ray diffractometry, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy are employed complementarily for material characterization. Cyclic voltammetry and galvanostatic charge-discharge tests are used to evaluate the specific capacitance and charge-discharge stability of the synthesized VO x NPs. Significant Findings: Particle size and mean valence of VO x NPs are controllable by adjusting the gas-phase synthetic conditions (atmosphere, temperature, gas flow rate). The specific capacitance of VO x NPs is shown to be proportional to the average valence of V, and the maximum specific capacitance (147.8 F/g) is achievable at an average oxidation state of 4.79 for vanadium. This work demonstrates a prototype study of fast and continuous production of VO x NPs with controlled material properties, showing promise in the tuning of cluster size and valence for the optimization of the corresponding supercapacitive performance.