关键词：
氮掺杂;竹炭;超级电容器;两次活化工艺;性能表征
摘 要：
以竹炭为前驱体、三聚氰胺为氮源、碳酸钾为预活化剂,采用两次活化工艺成功制备了氮掺杂竹活性炭超级电容器电极材料。利用扫描电镜(SEM)、透射电镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、比表面积及孔隙分析(BET)和X射线光电子能谱(XPS)等测试方法对制备的电极材料的形貌、结构、化学成分进行表征。通过控制活化过程中的炭碱比(质量比)优化样品的电化学性能,结果表明:炭碱比为1∶1时制备的NC-1样品比表面积高达1 984.4 m2/g,平均孔径为1.26 nm,样品具有清晰的介孔以及内部蠕虫状的微孔。炭材料中氮元素和氧元素含量(质量分数)分别为2.20%和4.65%,有利于增加活性炭表面的亲水性和赝电容,从而提高其比电容量。经电化学性能测试,NC-1样品循环伏安曲线(CV曲线)具有良好的对称性,呈近似矩形;其中在低电势窗口出现明显的宽峰,表明充放电过程中材料表面的含氮官能团与电解液之间发生氧化还原反应,贡献赝电容。恒流充放电显示在1 A/g电流密度下质量比电容高达224 F/g,与未采用该活化工艺的样品比较提高了86.7%。在50 A/g电流密度下其质量比电容高达144 F/g,且在10 A/g下经5 000次循环充放电后仍可达到93%的初始电容保持率,显示了氮掺杂竹活性炭超级电容器电极材料较优异的电化学性能和稳定的循环性能。
译 名：
Preparation and examination of nitrogen-doped bamboo porous carbon for supercapacitor materials
作 者：
HAN Zunqiang;ZHONG Weiting;WANG Kun;College of Materials Science and Technology,Beijing Forestry University;
关键词：
nitrogen doping;;bamboo porous carbon;;supercapacitor;;double activation system;;performance characterization
摘 要：
During the last decade,the scarcity of fossil fuels and the simultaneous increase of the greenhouse effect have stimulated intensive research on energy storage all around the world.Among the energy-storage devices available,supercapacitors(also called electrochemical capacitors) are the most efficient for high-power density applications.They are able to store and release energy in short time,being perfectly adapted for the quality of electricity required by hybrid and electric vehicles,tramways,diesel-engine starting,wind turbines,computers,lasers,and cranes.In the case of a hybrid vehicle,supercapacitors provide the peak power necessary during acceleration and recover the energy during deceleration and breaking.Fascinating carbons prepared by template processes have been extensively studied but their applications are limited because of the complicated production methods and relatively high cost.In this study,bamboo carbon,melamine and potassium carbonate were used as the precursor,nitrogen source and pre-activator,respectively,to successfully produce the nitrogen-doped bamboo porous carbon supercapacitor electrode materials through two-step activation processes.The morphology,structure,and chemical composition of the prepared electrode materials were characterized by scanning electron micrograph(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),Raman,Brunauer-Emmett-Teller(BET) and X-ray photoelectron spectroscopy(XPS).By adjusting the ratio of carbon and K_2 CO_3,the electrochemical performance of the samples was optimized.The results showed that the optimized sample(NC-1) exhibited the clear mesopores and internal worm-like micropores,with 1 984.4 m2/g BET surface area and 1.26 nm of average pore diameter.NC-1 had clear mesopores and internal worm-like micropores.The contents of nitrogen and oxygen in the carbon material were 2.20% and 4.65%,respectively,which was beneficial to increase the hydrophilicity and pseudocapacitance of the activated carbon surface,thereby improving its specific capacitance.According to the electrochemical performance test,the cyclic voltammetry(CV) curve of NC-1 had good symmetry and was approximately rectangular.Among them,a wide peak appeared in the low potential window,indicating that a redox reaction occurred,which was beneficial to the electric double layer effect of activated carbon by increasing the surface hydrophilicity and pseudocapacitance.The mass specific capacitance of this sample reached 224 F/g at 1 A/g,which was 86.7% higher than the control sample.The capacitance still remained 144 F/g as the current density increased to 50 A/g,and the capacitance retention of 93% over 5 000 cycles was also determined at 10 A/g,demonstrating the excellent electrochemical and stable cycle performance.
