V_2O_5·nH_2O纳米带的简单合成及其电容性能研究

Facile Synthesis and Capacitive Properties of V_2O_5·nH_2O nanobelts

以V2O5为原料,采用直接水合的简单方法合成了V2O5·n H2O纳米带.利用XRD和IR测试样品的结构和组成,利用SEM测试其形貌.通过循环伏安和恒流充放电法测试了V2O5·n H2O在1mol·L-1KNO3、Na NO3和Li NO3电解液中的电容性能.电化学测试结果表明,V2O5·n H2O在KNO3电解液中电容性能最好.当电压窗口为(-0.4-0.8)V、电流密度为200m A·g-1时,V2O5·n H2O电极在第600次充放电循环时展现出最大的比电容148.1F·g-1;再循环1400次后的比电容为142.6F·g-1,比电容保持率为96.3%.当电流密度从200 m A·g-1增大到800m A·g-1时,其比电容值为115.6 F·g-1,1000次循环后比电容保持率为97.9%,表明材料在大电流密度下的充放电性能较好.因此,直接水合制备的V2O5·n H2O纳米带适合做超级电容器的电极材料.

V2O5·nH2O nanobehs were synthesized by easy hydration method without any additives or templates with commercial V2O5 powders as raw material. The structure and morphology of as-prepared sample were analyzed by XRD, IR and SEM. The capacitive properties of V2O5·nH2O nanobelts were determined by cyclic voltammetry and galvanostatic charge-discharge test in 1mol·L^-1 KNO3, NaNO3 and LiNO3 neutral electrolyte solutions. The results revealed that V2O5·nH2O nanobelts showed the best capacitive properties in KNO3 solution. In the poten- tial range of （ -0.4 -0.8）V, V2O5·nH2O electrode delivered the highest specific capacitance of 148.1 F·g^-1 at 600th cycle in KNO3 solution at a current density of 200 mA·g^-1. After 1400 cycles, the capacitance retention was 99.3%. Furthermore, the V205 . nH20 electrode still exhibited specific capacitance of 115.6 F . g^-1 and excellent cycle stability at high current density of 800 mA·g^-1 These results indicate that V2O5·nH2O nanobehs are desirable for electrode material of supercapacitor in KNO3 electrolyte solution.