碳点MnO_(2)修饰碳布复合电极的电容性能

Capacitance Performance of Carbon Dot MnO_(2) Modified Carbon Cloth Composite Electrode

通过一种自下而上的高温裂解方法制成一种碳点(CD),并在此基础上以碳布(CC)为衬底合成了碳点修饰的二氧化锰(CD/MnO_(2))复合电极。对合成的CD/MnO_(2)/CC进行表征分析,发现生成的CD/MnO_(2)较均匀地生长在碳纤维上,高分辨率透射电子显微镜(HRTEM)下CD/MnO_(2)呈分层纳米片状。对CD/MnO_(2)/CC进行电化学测试,发现该复合电极在Na2SO4水溶液中展现出了极高的面积比容量(1 mV/s扫描速率下达1400 mF/cm^(2))和超长的循环寿命(4000次循环后电容保持率达87.2%)。最后将复合电极、聚乙烯醇(PVA)和Na2SO4导电凝胶组装成柔性对称超级电容器。结果表明超级电容器扩展了电位窗口,达到了-1~1 V,在30 mV/s的扫描速率下,面积比容量为401 mF/cm^(2)。在180°和90°的弯折下,面积比容量变化不大,展现了良好的弯曲耐受度。

A kind of carbon dot(CD)was made by a bottom-up high-temperature pyrolysis me-thod,and on this basis,a carbon dot modified manganese dioxide(CD/MnO_(2))composite electrode was synthesized with carbon cloth(CC)as substrate.The synthesized CD/MnO_(2)/CC was characterized and analyzed.It is found that CD/MnO_(2)is uniformly grown on the carbon fiber,and the CD/MnO_(2)is in the shape of layered nano-sheet under the high-resolution transmission electron microscope(HRTEM).The electrochemical test of CD/MnO_(2)/CC shows that the composite electrode has extremely high area specific capacity(1400 mF/cm^(2)at a scanning rate of 1 mV/s)and ultralong cycle life(the capacitance retention rate reaches 87.2%after 4000 cycles)in Na2SO4 aqueous solution.Finally,the composite electrode,polyvinyl alcohol(PVA)and Na2SO4 conductive gel were assembled into a flexible symmetrical supercapacitor.The results show that the supercapacitor expands the potential window to-1~1 V.At a scanning rate of 30 mV/s,the area specific capacity is 401 mF/cm^(2).Under 180°and 90°bending,the area specific capacity doesn’t change much,showing good bending tolerance.