关键词: 电化学电容器, 氮化钒纳米晶, 负极材料, 比表面积, 比电容

Abstract: Nanocrystalline vanadium nitride (VN) materials were synthesized by high temperature ammonia (NH₃) reduction of vanadium oxide (V₂O₅). The structure and morphology of VN materials were characterized by XRD，SEM and TEM, while the specific surface area, pore size distribution and supercapacitive behavior by N2 absorption, cyclic voltammetry (CV) and constant current charge-discharge measurements in 1 mol?L-1 KOH electrolyte. The results showed that the VN sample belonged to the cubic crystal system (Fm3m [225])，and had homogeneous surface and appeared nearly spherical with uniform size. As the reaction time was extended to 12 h，small particles were interconnected with each other to form some mesopores. The specific capacitance of VN-c was 192 F.g^-1 at current density of 50 mA.g^-1，and retained 150 F.g^-1 after 1000 cycles. The VN sample possessed both capacitive properties of electrical double-layer and pseudocapacitive properties of redox reactions.

Key words: electrochemical capacitor, nanocrystalline vanadium nitride, negative electrode materials, specific surface area, specific capacitance