Synthesis of mesoporous niobium nitride nanobelt arrays and their capacitive properties

Mesoporous niobium nitride nanobelt arrays (Nb4N5 NBAs) are fabricated directly on Nb foils by a hydrothermal reaction in KOH, protonation treatment in HNO3, and calcination in an NH3 ambient. The morphology, composition and pore structure of the Nb4N5 NBAs are characterized in details. In addition, the mesoporous Nb4N5 NBAs electrode has good specific capacitance (37.4 mF cm−2, or 124 F g−1) and delivers excellent rate performance due to the high porosity and good electron conductivity boding well for application to next-generation energy storage systems.