水热法合成Bi2WO6/CNOs纳米材料及其电化学性能

为了提高超级电容器的性能, 尽可能减少环境污染, 电极材料尤其是低成本、高能量密度的环保型电极材料受到人们越来越多的关注。本研究采用水热法制备了Bi₂WO₆/CNOs (CNOs, 纳米洋葱碳)和Bi₂WO₆纳米材料。采用扫描电子显微镜(SEM)和X射线晶体衍射(XRD)对产物的形貌、结构进行分析, 并通过循环伏安法、恒电流充放电测试、交流阻抗对材料的电化学性能进行评价。结果表明, 以1 mol·L^-1 KOH为电解液, 电流密度为2 mA·cm^-2时, Bi₂WO₆/CNOs与纯相Bi₂WO₆的比电容分别为328和218 F·g^-1; 电流密度为5 mA·cm^-2时, 经过300次循环, Bi₂WO₆/CNOs的比容量保持率比纯相Bi₂WO₆提高了34.37%。可见, 在Bi₂WO₆中加入CNOs能明显改善Bi₂WO₆的电化学性能。

Electrochemical Performance of Bi2WO6/CNOs Nanocomposites Synthesized via a Hydrothermal Method

In order to enhance the performance of supercapacitor and reduce environmental pollution as far as possible, electrode materials especially low-cost and eco-friendly electrode materials with high energy density have attracted a great deal of attention. In this paper, Bi₂WO₆/CNOs (CNOs, Carbon Nano Onions) and Bi₂WO₆ nanocomposites have been synthesized via a hydrothermal method. And the structures and morphologies of samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performances of the as-prepared samples were investigated by cyclic voltammetry, galvanostatic charge - discharge measurements and electrochemical impedance spectroscopy. At a current density of 2 mA·cm^-2, the specific capacitance of the Bi₂WO₆/CNOs and Bi₂WO₆ was 328 F·g^-1 and 218 F·g^-1 with 1 mol·L^-1 KOH served as electrolyte, respectively. After 300 charge-discharge cycles at a current density of 5 mA·cm^-2, the specific capacitance of the Bi₂WO₆/CNOs improved 34.37% compared with pure Bi₂WO₆. Thus, CNOs can enhance the electrochemical performance of Bi₂WO₆ obvously.