微波活化甘蔗渣合成活性炭及其电化学电容特性

以甘蔗渣为原料,ZnCl2为活化剂,分别采用微波加热活化和管式炉加热活化制备了一系列活性炭材料,并研究了微波活化法制备的活性炭在水或离子液体电解液体系中的电容特性.氮气吸附测试表明:活化剂的浓度与活性炭的孔结构密切相关,加热方式对孔径结构的影响不大,但微波活化法在加热效率和均匀性方面具有明显的优势.当活化剂的浓度从20wt%增大到60wt%时,活性炭的平均孔径从2.5nm逐渐增大到7.0nm.电化学测试表明:在离子液体中炭材料的电容性能与其孔径大小密切相关,孔径尺寸越大,其电容性能越好.离子液体电容器能提供远高于水相电容器的能量密度.AC60在功率密度为2.5kW/kg时,仍能提供9.2Wh/kg的能量密度.

Sugarcane Bagasse-Based Activated Carbons Prepared by Microwave Activation and Its Electrochemical Capacitive Performance

Two series of activated carbon materials had been successfully prepared by microwave activation and tube furnace heating treatment,for which sugarcane bagasse and ZnCl2 were used as carbon resource and activating agent respectively.The electrochemical capacitive performance of activated carbon prepared by microwave activation was studied in aqueous and ionic liquid electrolytes.Nitrogen sorption determination shows that the pore structure is closely related to the concentration of activating agent,and the activating method shows rarely effect on the pore structure,while the microwave activation possesses significant advantage in heating efficiency and homogeneity.Structural characterization reveals that the pore size of activated carbons could be tuned from 2.5 nm to 7.0 nm as the concentration of ZnCl2 solution increases from 20 wt% to 60 wt%.As evidenced by electrochemical measurements,the pore size plays a crucial role for the capacitive performance of activated carbons in ionic liquid electrolyte,and the larger the pore size,the better the capacitance.Ionic liquid supercapacitor could deliver much higher energy density than aqueous supercapacitor.AC60 could deliver 9.2 Wh/kg of energy density while maintaining 2.5 kW/kg of power density.