摘要
商业化的多壁碳纳米管通常是相互缠绕且紧密团聚,长度高达数十微米,不利于电解液离子的传输,尤其是难以利用碳纳米管内部空间。本文通过简单的化学氧化方法从横向和纵向同时裁剪多壁碳纳米管,形成弯曲的石墨烯带(CGS),将其浸入0.1 mol L^(-1)高锰酸钾溶液中,合成了CGS-MnO_(2)复合材料。利用FESEM、TEM、XRD、Raman对CGS-MnO_(2)的形貌和结构进行详细表征,结果表明无定形MnO_(2)成功地锚定在CGS的表面。在三电极体系中,CGS-MnO_(2)在2 mV s^(-1)的扫速下电容值达到236 F g^(-1),甚至在100 mV s^(-1)下电容仍能保持127 F g^(-1),远高于对比样品的电容值,例如MWCNTs(15 F g^(-1)),CGS(88 F g^(-1))和MWCNTs-MnO_(2)复合材料(111 F g^(-1))。此外,该材料还表现出优异的循环稳定性能,循环1000次后电容仍然保持97%。
Multi-wall carbon nanotubes(MWCNTs)have achieved mass production,but their lengths are in the millimeter range,which is unfavorable for the diffusion of electrolyte ions into their innermost tube.We report an oxidation method to simultaneously cut and unzip MWCNTs along transverse and longitudinal directions,which leads to the formation of curved graphene sheets(CGSs).SEM shows that the curved morphology was retained but the diameters were large after unzipping.This could be caused by the interaction of oxygen-containing functional groups between layers on the edges of the CGSs.Because of the larger number of active sites the specific capacitance is improved.To further increase the capacitive performance,a sample was put into a 0.1 mol L^(−1) KMnO_(4) to incorporate MnO_(2).The microstructure of the resulting CGS-MnO_(2) hybrid was revealed by electron microscopy,Raman spectroscopy and powder X-ray diffraction.The results indicate that amorphous MnO_(2) successfully grew on the surface of the CGSs.The capacitive behavior was measured by cyclic voltammetry in a 1 mol L^(-1) Na_(2)SO_(4) solution.The CGS-MnO_(2) had a specific capacitance of 236 F g^(-1) at 2 mV s^(-1)(even 127 F g^(-1)at 100 mV s^(-1)),which is superior to that of MWCNTs(15 F g^(-1)),CGS(88 F g^(-1))and MWCNT-MnO_(2)(111 F g^(-1)).In addition,excellent cycling performance was achieved for the CGS-MnO_(2) hybrid electrode with a 97% capacitance retention over 1000 cycles.
作者
李小燕
王强
王欢文
LI Xiao-yan;WANG Qiang;WANG Huan-wen(School of Chemistry and Chemical Engineering,Shanxi University,Taiyuan 030006,China;State Key Laboratory of Coal Conversion,CAS Key Laboratory of Carbon Materials,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China;Faculty of Material Science and Chemistry,China University of Geosciences,Wuhan 430074,China)
出处
《新型炭材料》
SCIE
EI
CAS
CSCD
北大核心
2021年第4期835-842,共8页
New Carbon Materials
基金
国家自然科学基金(21872162)
中国科学院炭材料重点实验室开放基金(KLCMKFJJ2009).
关键词
多壁碳纳米管
弯曲石墨烯
裁剪
超级电容器
Multi-walled carbon nanotubes
Curved graphene
Unzipping
Supercapacitor
作者简介
通讯作者:王强,副研究员.E-mail:wqiang@sxicc.ac.cn;李小燕,讲师.E-mail:xiaoyanli1975@163.com。
