(363g) Nanostructured Vanadium Nitride for Supercapacitor Applications

There is a dire need to provide a sustainable solution to the growing global demand for energy.  It is this incessant demand that is the primary driver fueling various new current and emerging technologies including lithium ion batteries, supercapacitors and fuel cells. Supercapacitors hold a unique place among these energy storage devices on account of their high power density and long cyclability. Supercapacitors are electrochemical charge storage devices capable of delivering large bursts of charge over a very short period of time. It is due to this unique capability that supercapacitors occupy a very important role in the growing alternative energy field. High surface area carbons, hydrated ruthenium oxide and MnO₂are among the primary materials being considered for supercapacitor applications. Our group has previously identified vanadium nitride (VN) as a promising electrode material for supercapacitors on account of its high energy density with capacitances as high as 1300 F/g. 

In this work, we present a facile one-step direct mechanical milling approach for the synthesis of nanostructured vanadium nitride (VN) particles. The electrochemical mechanism and material properties influencing the supercapacitor properties of VN have been explored. The surface properties of VN have also been studied using X-ray photo-electron spectroscopy (XPS) and correlated to the electrochemical characteristics. Stable capacitances of upto 100F/g are reported here for VN prepared using High Energy Mechanical Milling (HEMM). Degradation of the capacitance upon cycling is studied and possible mechanisms for the same have been proposed. Results of these studies will be presented and discussed.