分级多孔纳米炭纤维的结构及电容性能

Structure and capacitive properties of hierarchical porous carbon nanofibers

以酚醛树脂为碳源、PVP为纺丝助剂、纳米MgO颗粒为模板剂,通过静电纺丝法制得酚醛树脂基纳米炭纤维,经过炭化、KOH活化、酸洗后得到分级多孔纳米炭纤维,利用SEM、XRD、XPS、拉曼光谱仪及氮气吸脱附实验,对所制多孔纳米炭纤维的结构和形貌进行表征,并将其作为模拟电容器的电极,利用循环伏安、恒电流充放电及交流阻抗方法测试了材料的电化学性能。结果表明,KOH活化引入了数量可观的微孔,所得纳米炭纤维表现出明显的"微孔-中孔-大孔"分级孔分布的特点,其比表面积达到1058.4m^2/g,总孔容为1.64cm^3/g。电化学测试结果表明,所制分级多孔纳米炭纤维在6mol/L KOH电解液中显示出优异的电容性能,在0.2A/g的电流密度下,其放电比容量达到198F/g,在20A/g电流密度下,电容保持率达到65%。

With phenolic resin as carbon source,PVP as spinning agent and nano-MgO particles as template,the phenolic resin-based carbon nanofiber was prepared by electrospinning.Followed by carbonization,KOH activation and acid pickling processes,the carbon nanofiber with hierarchical porous structure was obtained.By means of SEM,XRD,XPS,Raman spectroscopy and N 2 adsorption-desorption tests,the morphology and structure of the porous carbon nanofibers were characteriezed.Moreover,the cyclic voltammetry,galvanostatic charge-discharge and alternating current impedance methods were adopted to investigate the electrochemical properties of the as-prepared materials used as the simulated capacitor electrodes.The results show that the carbon nanofiber with KOH activation has a larger number of micropores,and exhibits a well-devoloped hierarchical porous structure including micropores,mesopores and macropores with a specific surface area of 1058.4 m 2/g and a total pore volume of 1.64 cm 3/g.In addition,the results of electrochemical tests indicate that the obtained hierarchical porous carbon nanofiber exhibits a remarkable capacitance perfomance in 6 mol/L KOH electrolyte,its discharge specific capacity reaches 198 F/g at a current density of 0.2 A/g and the capacitance retention rate reaches 65%at a current density of 20 A/g.