碱木质素基多孔炭材料的制备及其在超级电容器中的应用

Preparation of Alkali Lignin-based Porous Carbon Material and Its Application in Supercapacitors

以碱木质素为原料,按照其与NaOH质量比(简称碳碱比)1∶1、1∶3、1∶5进行混合,利用实验室小型管式炉热裂解制备碱木质素基多孔炭材料,对多孔炭材料进行了场发射扫描电子显微镜、粒径、有机元素和傅里叶变换红外光谱分析;并采用自制碱木质素基多孔炭材料制备超级电容器,通过循环伏安测试和恒流充放电测试分析其电化学性能。结果表明,碱木质素基多孔炭材料形貌都呈球状或半球状,有大量孔结构,表面粗糙有起伏,碳碱比从1∶1变化到1∶5,平均粒径分布逐渐减小。碳碱比为1∶1时,碱木质素基多孔炭材料制备的超级电容器电化学性能最优,随着电流密度从0.1A/g增加到1A/g,其比电容从71F/g下降到62F/g,下降13%左右;在1A/g的超大电流密度下充放电循环500次,比电容依然维持在62F/g,循环性能良好。

In this paper, the porous carbon materials were prepared by pyrolyzing alkali lignin with sodium hydroxide according to the carbon-base ratio of 1∶ 1,1∶ 3,1∶ 5 in a laboratory tube furnace. And the porous carbon material was analyzed by ESEM, particle size analyzer, organic element analyzer and infrared spectrum.Supercapacitors were prepared using alkali lignin porous carbon materials, and their electrochemical performance was investigated by cyclic voltammetry and galvanostatic charge and discharge tests. The results showed that the morphology of the alkali lignin-based porous carbon materials were spherical or hemispherical, with a large number of pore structures, and rough surface. However, as the carbon-base ratio increasing from 1∶ 1 to 1∶ 5, the average particle size distribution gradually decreased. When the carbon-base ratio was 1∶ 1, the supercapacitor had the best electrical performance. As the current density increases from 0.1 A/g to 1 A/g, the specific capacitance decreased from 71 F/g to 62 F/g, which decreased about 13%. The specific capacitance was still maintained at 62 F/g when it circulated 500 times at an ultra-high current density of 1 A/g, its cycle performance was good.