Ammonolysis Synthesis of Nickel Molybdenum Nitride Nanostructure for High-performance Asymmetric Supercapacitor

Binary metal nitride nanorods of nickel-molybdenum nitride (Ni3Mo3N) are synthesized by a one-pot hydrothermal method followed by calcination at 400 °C and ammonolysis at 800 °C. The material is characterized by electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Ni3Mo3N nanorods are tested as an electrode material for supercapacitor and 264 C g-1 specific capacity is exhibited at 0.5 A g-1 current density with the specific capacity of 108 C g-1 at high current density (5 A g-1) revealing 41% of rate capability. The Ni3Mo3N electrode retained 81.4 % of the specific capacity after 1000 cycles at 5 A g-1 current density in the three-electrode system. The full cell device with Ni3Mo3N nanorods as a cathode, activated carbon (AC) as an anode, and porous cellulose paper as a separator in 6 M KOH electrolyte, the Ni3Mo3N//AC asymmetric cell is assembled and exhibited the high specific capacity of 157 C g-1 at 1 A g-1 current density. Moreover, the asymmetric cell displayed excellent cycling stability of 95.7 % at a high current density (5 A g-1) after 3000 cycles and showed a maximum energy density of 34.89 Wh kg-1 at 800 W kg-1 power density. The overall electrochemical performance of Ni3Mo3N nanorods in a supercapacitor is remarkable and suggesting an ideal candidate for future electrochemical devices.