具有均一尺寸球形碳气凝胶的制备及其储能研究

Abstract

用不同pH的碳酸钠溶液作为催化剂催化间苯二酚和甲醛的缩聚反应得到有机凝胶，后经高温碳化得到碳气凝胶。采用SEM、TEM和N2吸脱附测试方法对所得材料进行表征，还通过循环伏安法和恒流充放电测试手段对其电化学性能进行详细的研究。SEM测试结果表明，随着pH数值的增加，所得碳气凝胶颗粒的形貌呈现出由独巨体到球形再到独巨体的变化过程，表明通过调节催化剂的pH可以得到不同形态的碳气凝胶，并且当pH为10.49时所得碳气凝胶材料具有尺寸均一的连续球形结构。N2吸脱附测试结果表明所得球形碳气凝胶材料的比表面积可达526.1 m2/g。循环伏安法和恒流充放电法的测试结果表明同独巨体碳气凝胶相比，粒径高度均一的球形碳气凝胶具有更优异的电化学性能，材料的比电容可以达到85.39 F/g，以其构建的超级电容器比电容可以达到76.72 F/g。 Different pH values of sodium carbonate solution were used as catalyst for condensation of resorcinol and formaldehyde to obtain organic gels. After high temperature carbonization, the organic gels were transformed to carbon aerogels. The obtained materials were characterized by SEM, TEM and N2 adsorption desorption test. In addition, the electrochemical performance, such as cyclic voltammetry and galvanostatic charging and discharging tests, was also conducted. SEM results show that the morphologies of carbon aerogels exhibit the transformation from sole macrosomia to sphere and eventually to sole macrosomia via elevating the pH value of precursor solution. It can be noted that different forms of carbon aerogels can be obtained via regulating the pH of the precursor solution. Especially, when the pH of sodium carbonate solution is 10.49, the prepared carbon aerogels exhibit spherical structure with uniform particle size. N2 adsorption and desorption tests show that the specific surface area of the spherical carbon can up to 526.1 m2/g. Cyclic voltammetry and galvanostatic charging and discharging tests show that the uniformly spherical carbon aerogels expressed more superior electrochemical performance than that of resulted monolithic based carbon aerogels. The specific capacitance of the spherical carbon aerogels can reach 85.39 F/g. Meanwhile, the specific capacitance of spherical carbon aerogels based supercapacitor can get 76.72 F/g.