RF炭气凝胶孔结构的控制及其电化学性能研究

Pore structure modification and electrochemical performance of carbon aerogels from resorcinol and formaldehyde

考察了在以间苯二酚(R)和甲醛(F)为原料,碳酸钠(C)为碱性催化剂,通过溶胶-凝胶过程和常压干燥方法制备RF炭气凝胶过程中CO2活化对炭气凝胶孔结构的影响,并通过恒流充放电和循环伏安法测试其电化学性能。结果表明:CO2活化可明显提高炭气凝胶BET比表面积(SBET)和孔容(vtotal)。RF炭气凝胶在900℃下活化3h,SBET从未活化时的633m2/g提高到1271m2/g;相应的电化学测试结果表明,以1mA/cm2的电流充放电,其比电容可从未活化样的81F/g增加到172F/g;以30mA/cm2的电流进行充放电试验,活化样的比电容仍可达到131F/g。

Carbon aerogels were prepared using a sol-gel process with resorcinol and formaldehyde as raw materials and sodium carbonate as catalyst, followed by ambient drying and carbonization. They were then activated by carbon dioxide. The activated materials were used as electrode materials of electric double-layer capacitors and their electrochemical behavior was characterized by constant current charge-discharge experiments and cyclic voltammetry in an electrolyte of 6 mol/L KOH aqueous solution. Results showed that the BET surface area and total pore volume of the aerogels were increased greatly by CO2 activation. When the carbon aerogel was activated by CO2 at 900 ℃ for 3 h, its BET surface area increased from 633 m2/g to 1271 m2/g, and the corresponding specific capacitance increased from 81 F/g to 172F/g at a current density of 1 mA/cm2. When the current density was increased from 1 to 30mA/cm2, the specific capacitance of the activated sample decreased from 172 to 131 F/g, indicating that the sample possessed an excellent power capability.