氮化钒的制备及其电化学性能

Preparation and electrochemical properties of vanadium nitride

以V2O5为原料,采用熔融水淬法制备V2O5干凝胶,经氨气程序升温还原V2O5得到VN粉体.通过XRD,循环伏安法、恒电流充放电和交流阻抗等方法对V2O5原料、干凝胶和VN的物相结构与电化学性能进行表征测试,研究VN的制备条件对电化学性能的影响.结果显示,V2O5原料经过熔融水淬处理后,晶体结构发生较大的变化.在空速为300 h-1、升温速率为2℃.min-1下,氨气还原V2O5制得的VN在1 mol.L-1的KOH碱性电解液中电化学反应电阻最小.当放电电流密度为0.25 A.g-1时,VN电极材料的比电容值达到74.2 F.g-1,且恒流充放电曲线对称性较好.

The V2O5 gel was prepared by quenching melting V2O5 into a bath of deionized water and VN powder was synthesized by reacting V2O5 gel with NH3 in a temperature programmed manner. The physical characterics of raw materials, the dry gel and VN powder were researched by XRD, cyclic vohammetry, chronopotentiometry and A.C. impedance. The effects of the preparation conditions of VN on the supercapaeitive performance were also studied. XRD test results showed that V2O5 crystal structure got a lot of change after melting-quenching process. The VN powder, which was obtained using space velocity 300 h^ - 1 and 2 ℃2 · min^ -1 heating rate, pres-ented minimal Faradic resistance in 1 mol · L^-1 KOH alkaline electrolyte solution. The specific capacitance of VN was 74. 2 F · g^-1 at charge current density 0.25 A · g^-1, and constant current charge-discharge curve sym-metry was the best.