Controlled Aerosol-based Synthesis of Vanadium Oxides Nanoparticle for Supercapacitor Applications

Abstract

BackgroundNanostructured mixed-valence vanadium oxides (VOx) are attractive as electrode materials for supercapacitor applications. Development of suitable synthetic and characterization methods for the fabrication of VOx nanostructures with controlled properties is of crucial importance. MethodsA continuous aerosol-based synthetic route with in-situ mobility size characterization is developed to fabricate VOx 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 VOx NPs. Significant FindingsParticle size and mean valence of VOx NPs are controllable by adjusting the gas-phase synthetic conditions (atmosphere, temperature, gas flow rate). The specific capacitance of VOx 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 VOx NPs with controlled material properties, showing promise in the tuning of cluster size and valence for the optimization of the corresponding supercapacitive performance.