玉米面衍生的三维孔碳电极材料的绿色合成与超级电容器性能

Green synthesis and supercapacitor performance of 3D porous carbon electrodes derived from corn meal

为了获得性能优异的超级电容器电极材料,选择廉价的玉米面作为碳前驱体,利用简单的硬模板方法,以容易水洗去除的碳酸钠为大孔模板、氢氧化钾为活化试剂,制备了兼具大孔、介孔和微孔的三维分级孔碳材料.分别采用扫描电镜、氮气吸附脱附、恒流充放电、循环伏安及交流阻抗等测试方法,对材料的形貌、孔结构和电化学储能性能进行表征.结果表明:所得孔碳材料具有良好的分级孔结构特点,其比表面积高达1 365.2 m2/g.电流密度为0.5 A/g时,比电容高达245 F/g;电流密度为20 A/g时,电容量保持率为93.5%.在5 A/g的电流密度下,循环10 000圈后,电容量仍能保持在97.3%.组装所得对称超级电容器的能量密度和功率密度分别达到29.2 W·h/kg和500.6 W/kg,说明该孔碳材料在超级电容器方面具有很好的应用前景,合成方法成本低、绿色环保,预计能够在大规模制备三维孔碳基纳米材料方面得到广泛应用.

In order to obtain the electrode materials with excellent performances for supercapacitors,3 D hierarchical porous carbon materials with interconnected macro-,meso-and micropores were fabricated by a simple hard-template method,using corn meal as a renewable carbon precursor,which is a common low-cost food, while Na2 CO3 is used as an easily-removable macroporous template and KOH is chosen as activation reagent. The morphologies, pore structures and the electrochemical performances were characterized by scanning electron microscope, nitrogen adsorption-desorption,galvanostatic charge-discharge,cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The results indicate that the obtained porous carbon material with hierarchical porous structure has a high specific surface area of 1 365.2 m^2/g.It exhibits a high specific capacitance of 245 F/g at 0.5 A/g and 93.5% capacitance retention at 20 F/g. It also displays excellent cycling stability with capacity retention of 97.3% at 5 A/g after 10 000 cycles. The symmetric supercapacitor delivers a high energy density of 29.2 W·h/kg and a power density of 500.6 W/kg. It demonstrates that the obtained porous carbon has great prospect for supercapacitors and this low-cost and green synthesis route could be widely used to fabricate 3D porous carbon-based nanomaterials in a large scale.