Preparation and Electrochemical Properties of NiCo2S4@Carbon Nanotube Constructed Flexible Film Electrode for Supercapacitors
周阅微 南京大学现代工程与应用科学学院, 南京 210093
南京外国语学校, 南京 210008 
季昀辉 南京大学现代工程与应用科学学院, 南京 210093  
谭徜彬 南京大学现代工程与应用科学学院, 南京 210093  
宋伟杰 南京大学现代工程与应用科学学院, 南京 210093  
许亮亮 南京外国语学校, 南京 210008  
唐少春 南京大学现代工程与应用科学学院, 南京 210093 
摘要: 以浮动催化化学气相沉积致密超薄碳纳米管薄膜(CNTF)为基体,通过两步酸处理使薄膜内致密的碳纳米管(CNT)分开并赋予其活性官能团,CNTF由超疏水转变为超亲水性,然后在CNT表面生长均匀的前驱体包覆层,离子进入超亲水薄膜内部确保了高负载量,最后进行液相硫化制得NiCo2S4@碳纳米管构筑柔性薄膜(NiCo2S4@CNTF)电极。利用扫描电子显微镜、X射线衍射等对产物进行了表征,证明优化产物为NiCo2S4均匀包覆多壁CNT构筑而成的三维网状柔性复合薄膜,单根CNT的表面是厚度约70 nm的NiCo2S4纳米粒子构成的粗糙包覆层。该复合薄膜比电容达到270.3 mF·cm-2,即使在高电流密度2.5 mA·cm-2下充放电循环10 000次后仍保持很好的可逆性,电容保持率达93%,库伦效率持续稳定在92%附近;重复大变形(弯曲、折叠、卷曲)后能保持结构完整性和性能稳定性。同时,探讨了电化学性能与结构间的关系,并揭示了性能增强的内在机理。
关键词: 复合材料  碳纳米管薄膜  柔性电极  合成  超级电容器
基金项目: 国家自然科学基金(No.11374136)、江苏省自然科学基金(No.BK20161396)和中央高校基本科研业务费(No.021314380073)和南京大学技术创新基金(No.02131480608203)资助项目。
Abstract: The NiCo2S4@carbon nanotube (CNT) constructed flexible film(NiCo2S4@CNTF)electrodes was synthes-ized by a new top-down route using dense and ultrathin carbon nanotube films (CNTF)from floating catalytic chemical vapor deposition as a support. The synthesis included two-step acid treatment of a dense-packed CNTF leading to a three-dimensionally porous conductive matrix, growth of uniformNiCo2(CO3)1.5(OH)3precursor on each CNT, followed by solution-based sulfidation. Meanwhile the two-step acid treatment transformed hydrophobic CNTF to be highly hydrophilic, which made its interior to be highly ion-accessible and well-separation of adjacent CNTs in a 3D space, thus assured high loadings. The products were characterized by X-ray diffraction, scanning electron microscopy and other techniques. The results indicatedthat the optimal products were flexible composite filmswith a 3D network structure constructed by NiCo2S4 coated CNTs. The NiCo2S4 nanoparticle coating was rough with a thickness of~70 nm, which is benefit for providing active sites for electrochemical energy storage. The composite film electrode had a specific capacitance of 270.3 mF·cm-2 at 0.5 mA·cm-2, and exhibited excellent cycling stability with 93% of initial capacitance even after 10 000 cycles at a high current density of 2.5 mA·cm-2. The coulombic efficiency kept at around 92% with fluctuations during the whole cycling. Also, the composite film electrode kept good structure integrity after repeated large deformations. The relationship been the specific nanostructure and electrochemical performance was discussed in detail, and involved mechanism was also revealed.
Keywords: composite materials  carbon nanotube films  flexible electrodes  synthesis  supercapacitors
投稿时间:2019-04-14 修订日期:2019-06-11
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