Vanadium nitride with surface single specie oxide via vanadium-organic frameworks precursor

Vanadium nitride has a large potential window of 1.2 V and a high capacitance in the aqueous electrolyte attributed to vanadium oxides existed on its surface. However, these vanadium oxides, to be precise, V5+-containing oxides existed on vanadium nitride surface, always gradually dissolve in alkaline electrolyte as cycle progress goes, which largely affects cycling stability of the material. In this paper, we prepare imidazole-Vanadium-Organic Frameworks (imi-V-MOFs) as precursor to synthesize vanadium nitride containing single VO2 on material surface by method of facile chemical reaction. The prepared vanadium nitride shows a wide operating potential of 1.2 V and a capacitance of 149.5 F/g. The most amazing thing is that it has good cycle stability with capacitance retention of 85% after 1, 000 cycles at 1 A/g.