Nanoporous nitrides for super capacitors
Supercapacitors offer high capacitance in a small package and are able to release a large amount of energy very quickly. Transition metal nitrides are the recent class of materials for the application in electrodes of supercapacitors.
Among them, nanocrystalline vanadium nitride is especially promising. This direction of research is currently focused on the synthesis and electrochemical performance of vanadium nitride.
Major achievements
Nanoporous/nanocrystalline nitrides of vanadium are synthesised by a simple and elegant approach, ammonia reduction of vanadium pentoxide. The resulting materials retain the shape of oxide precursors, indicating a strong attachment of nanoscale grains, and have a high degree of texture (preferential orientation of grains). Due to these structural features, vanadium nitrides were found to have an improved rate capability. They demonstrate about 80% of their maximal capacitance at the current rate of 1 A/g in galvanostatic charge/discharge experiments in three aqueous electrolytes (1M KOH, 1M H2SO4, 3M NaCl). The previously reported effect of the dependency of capacitance on the material’s density on a current collector is successfully minimised.
Future plans and directions
Further research on the synthesis and properties of vanadium nitrides is planned. Other transition metal nitrides are also to be assessed.
