|The cover image: a high magnification transmission electron microscopy image of VN nanoparticles that exhibit enhanced supercapacitor response.|
A research team led by Carnegie Mellon University Materials Science and Biomedical Engineering Professor Prashant Kumta has discovered a nanocrystalline vanadium nitride (VN) material that is cheaper, more stable and produces a higher quality energy storage capacity for use in a variety of industrial and portable consumer electronic products.
Kumta said the discovery, published this summer in Advanced Materials Journal, has important implications for increasing the longevity of rechargeable car batteries, fuel cells and other battery-operated electronic devices.
We have found that synthesis of nanostructured vanadium nitride and controlled oxidation of the surface at the nanoscale is key to creating the next generation of supercapacitors commonly used in everything from cars, camcorders and lawn mowers to industrial backup power systems at hospitals and airports.—Prashant Kumta
Supercapacitors today generally use various forms of ruthenium oxide, a transition metal that is also expensive, selling for more than $100 per gram.
|Gravimetric capacitance (F/g) with varying VN nanocrystallite loading scanned at various rates (2~100mV/s) using 1M KOH electrolyte.|
Kutma and his team synthesized a new class of nanocrystalline transition metal nitrides (TMN) based on vanadium nitride. These new materials deliver a specific capacitance of 1,340 F/g when tested at low scan rates of 2mV/s and 554 F/g when tested at high charging rates of 100 mV/s in the presence of a 1M KOH electrolyte.
That exceeds the capacitance response of RuO2. The vanadium nitride is less expensive (about $50 per gram) and can store energy longer, according to Kutma.
Other project researchers included Tom Nuhfer, a materials science graduate student at Carnegie Mellon; and Wayne Jennings, a materials science researcher at Case Western Reserve University. The work was supported by Carnegie Mellon seed funding and a grant from the National Science Foundation.Resources:
“Fast and Reversible Surface Redox Reaction in Nanocrystalline Vanadium Nitride Supercapacitors”; D. Choi, G. E. Blomgren, P. N. Kumta; Advanced Materials, Volume 18, Issue 9, Pages 1178 - 1182