凝胶老化时间对炭气凝胶结构及电化学性能影响

The effect of gel aging time on the structure and electrochemical performance of carbon aerogels

以间苯二酚、间苯三酚、甲醛为反应原料,碳酸钠为催化剂,羧化壳聚糖作为软模板,通过溶胶-凝胶、丙酮置换、常压干燥和高温热解制备炭气凝胶。利用红外光谱(IR)、比表面积及孔径分析(BET)、扫描电镜(SEM)和电化学分析手段,对比讨论了不同凝胶老化时间对炭气凝胶的结构和电化学性能的影响。实验结果表明,随着凝胶老化时间的延长,炭气凝胶的平均孔径逐渐增大,比表面积逐渐减小,总孔体积逐渐增大,比电容逐渐减小。凝胶老化时间为12 h时生成的炭气凝胶,具有最大的比表面积(659.17 m2/g),比电容也达到最大值,在1.0 A/g电流密度下比电容为144.38 F/g。

Carbon aerogels were prepared by sol-gel process, acetone replacement, atmospheric drying and pyrolysis at high temperature using resorcinol, phloroglucinol, and formaldehyde as raw materials, sodium carbonate as catalyst, and carboxylated chitosan as soft template. The effects of different gel aging time on the structure and electrochemical properties of carbon aerogels were investigated by using IR, surface area analysis（BET）, scanning electron microscopy（SEM） and electrochemical analysis. The results show that, with the increase of gel aging time, both the average pore size and the total pore volume of carbon aerogels increase; while the specific surface area and the specific capacitance of carbon aerogels decrease. The carbon aerogels gel aged for 12 h show the largest specific surface area and the highest capacitance of 144.38 F/g at the current density of 1.0 A/g.