胆酸钴凝胶超分子自模板法制备一维纳米α-Co(OH)2及其电化学电容行为

以Co(NO₃)₂•6H₂O和胆酸钠溶液混合制备了超分子自组装凝胶纳米纤维, 以此凝胶纳米纤维为自模板, NH₃•H₂O为沉淀剂, 在温和条件下制备了纳米α-Co(OH)₂。X射线衍射(XRD)、红外光谱(FT-IR)、扫描电子显微镜(SEM)及透射电子显微镜(TEM)测试表征了其组成和微观结构。实验结果表明所得材料为纯相一维纳米纤维交错形成疏松网状结构的α-Co(OH)₂, 其直径在100~200 nm之间。用循环伏安和恒电流充放电等测试方法对α-Co(OH)₂电化学电容行为进行了研究, 结果表明: 所得α-Co(OH)₂在6 mol/L KOH溶液中, 0~0.5 V(vs Hg/HgO)电位范围内, 电流密度为1 A/g时, 其单电极比容量达到1200 F/g, 经过800周循环, 比容量稳定保持在初始容量的75%。其独特的纳米结构使其易于浸入电解液, 具有快速的电化学响应特性, 提高了电极材料的有效利用率, 这种自模板法为制备纳米电容器电极材料提供了简易的途径。

Electrochemical Capacitance Performance of One-dimensional Nano-α-Co(OH)2 Employing Cobalt-cholate Supramolecular Nanofibers Self-template Method

Nano-α-Co(OH)₂ was prepared via a facile strategy, in which the cobalt-cholate self-assembled spramolecular nanofibers as self-template were obtained by mixing sodium cholate solution with cobalt nitrate solution, and then the samples were obtained by adding depositing reagents NH₃•H₂O under ambient conditions. The composition and microstructure of the as-prepared samples were investigated by X-ray diffraction (XRD), infrared spectroscope (FT-IR), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results indicate that the as-prepared materials are pure phase α-Co(OH)₂ with one-dimensional nanofiber crossing loose network–like struture whose diameter is 100-200 nm. The electrochemical capacitive properties of the products were investigated using cyclic voltammetry and impedance spectroscopy in 6 mol/L KOH aqueous solution. The specific capacitance is up to 1200 F/g at a constant current charge/discharge test of 1 A/g within 0-0.5 V potential region, and stably keep 75% of initial capacitance after over 800 charge-discharge cycles. Its special nanostructure, with fast electrochemical response property, allows easy penetration of electrolyte and effective utilization of electrode material. This self-templating approach is therefore believed to provide a simple and convenient route to fabricate nanomaterials for application in supercapacitors.