Preparation of molybdenum nitride-molybdenum oxide composite electrode and its capacitance characteristics

Molybdenum nitride-molybdenum oxide composites were prepared by temperature-programmed deposition from the reaction of MoO₃ and NH₃. The composites were used to fabricate the positive-electrode in super-capacitor as an active material. The experimental results show that the crystal structures of composites and the proportion of nitride to oxide in the composites are affected markedly by the amount of reactants, temperature, time and cooling model. According to the X-ray diffraction results and theoretical calculation, the average crystal size of the prepared molybdenum nitride-molybdenum oxide composite is about 30 nm. By the measurements of cyclic voltammetry and charge and discharge at constant current in 3M H₂SO₄ solution, it was demonstrated that the capacitance of molybdenum nitride-molybdenum oxide composite electrode is as high as 340 F/g and 144 F/g respectively.